If thou art l)ono\vcil hy a fiiend, 
 Kijjlit wclooniL- sliiill he be, 
 
 To read, to study, not to lend, 
 But to return to me ; 
 
 Not that iiiipartfd knowledge doth 
 Dimini^li Itarniu^'s store, 
 
 But Books, I Hiid, if often lent, 
 Return to me no more. 
 
 Read slowly, pause frequently, think 
 seriously, keep cleanly, return duly, 
 icith th>t coruirs of th' havm not tiinuif 
 doirn. 
 
 Friend, please to heir this fact in mind 
 — That you have borrowe<l this hook 
 
 from the undersij,'ned ; 
 And if the act sliouUl cause you strife, 
 Do try to be honest for once in your 
 
 life, 
 Return this book i<> me quite clean, 
 Ami receive the thanks of 
 
 A. D. KEAN. 
 
 N. IJ. — Commence with tlie title 
 
 pa^<;, and read every word to the end 
 
 of the hook that you may do tlie 
 
 rillthnr jUHtii'c. 
 
 Ploaso keep a Cover on this 
 Book while using It. A.P. K. 
 
 Bought 
 
 Prirr S 
 
 \ 
 
 LIBRARY 
 
 uNivcRsirrw 
 
 Al I)
 
 SKETCH liOOlv OF I'OPUI.All OKOL.OOY. 
 
 POPULAR GEOLOGY: 
 
 SERIES OF LECTURES READ BEFORE THE PHILOSOPHICAL 
 INSTITUTION OF EDINBURGH. 
 
 5tscriplil)f .Sketches from a (ideologist's |)ortfolia. 
 
 B T 
 
 HUGH MILLER. 
 
 IXTIWDUCTORY RESUME OF THE PROGRESS OF GEOLOGICAL SCIENCE 
 WITHIN THE LAST TWO YEARS. 
 
 BT 
 
 MRS. MILLER. 
 
 NEW YORK: 
 
 ROBERT CARTER AND BROTHERS, 
 530 Broadway. 
 
 1882.
 
 THE REV. W. S. SYMONDS, 
 
 BXCTOR OF PEXDOCK, H E R E PO R D 8 H I R K. 
 
 DxAR Sir, 
 
 Am I pr('2:uining too much on my position, as merely the editor 
 of the following Lectures, when I ask leave to dedicate them to you? It ia 
 nnquestionably a liberty with the production of another which only very pecu- 
 liar circumstances can at all excuse. Yet, in the present case, I venture to 
 think that those peculiar circumstances do exist; and I feel assured he would 
 readily pardon me, whose work this is, and whose memory you so much revere. 
 Without your cobpcration, 1 believe that neither the " Cruise of the Betsey " 
 Bor tbeae pages could by this time have aeea the light. When my own over- 
 laden brain refused to do its duty, you gave me to hope, by offers of well- 
 timed assistance, that the ta«k before me might still t>e accomplished. Your 
 friendly voice, often heard in tones of sympathizing inquiry when I was una- 
 ble to endure your own or any other human presence, — even that of my dear 
 child, — was for a time the only sound that brought to my heart any promise or 
 cheer for the future. It was then, while unable to read the ver}' characters in 
 which tliey were written, that I put into your hands the papers containing 
 "The Cruise" and "Ten Thousand Miles over tlie Fossiliferous Deposits of 
 Scotland." You undertook the editorial duties connected with them con amort, 
 and performed your task in a manner that left nothing to be desired. 
 
 During the preparation of the present volume for the press, you have given 
 me all the advantage of your ready stores of information, both In carefully 
 ■onitinizing the text to see where any addition was required in the form of
 
 IV DEDICATION. 
 
 notes, and in referring me to the best authorities on every point regarding 
 which I consulted you. And while so doing, you have confirmed my own 
 judgment, — perhaps too liable to be swayed by partiality, — by expressing your 
 conviction that this work is calculated to advance the reputation of its author. 
 Long may you be spared to be, as now, the life and soul of those scientific 
 pursuits so successfully carried on in your own district! Many a happy field- 
 day may you enjoy in connection with that Society of which you are the hon- 
 ored president. Would that all associations throughout our country were as 
 harmless in their methods of finding recreation, as invigorating to body and 
 mind, and as beneficial in their results to the cause of science ! In exploring 
 the beautiful fields,^and woods, and sunny slopes of Worcestershire, and Here- 
 fordshire, in earnest and healthful communings with nature, and, I trust, with 
 nature's God, — the perennial springs of whose bounty are seldom quaifed in 
 this manner as they ought to be, — I trust that much, much happiness is in store 
 for you and for the other gentlemen of the Malvern Club,* to whom, as well as 
 to yourself, I owe a debt of grateful remembrance. 
 
 And for the higher and nobler work which God has given you to do, may 
 he grant you no stinted measure of his abundant grace, to enable you to per- 
 form it aright. 
 
 Ever believe me, dear Sir, 
 
 Yours most faithfully, 
 
 LYDIA MILLER. 
 
 / • The Malvern Club devotes stated periods,— monthly, I think,— to rambles over twenty or 
 l^ thirty miles of country, when the naturalists of whom it is composed,— botanists, geologists, 
 etc., — carry on the researches of their various departments separately, or in little groups of two 
 or three, as they may desire. They all dine afterwards together at an inn, or farm house, as the 
 case may be, where they relate the adventures of the day, discuss their favorite topics, and com- 
 pare their newly-found treasures. As a consequence of this, the Malvern Museum is a perfect 
 model of what a local museum ought to be. There Is no town or district of country where a 
 few young men, possessing the advantage of an occasional holiday, might not thus associate 
 themselves with the utmost odvantogc both to themselves and others.
 
 PREFACE 
 
 THE AMERICAN EDITION, 
 
 This new rolume, from the pen of Hugh Miller, is a legacy 
 wholly unlooked for by the American public. It was known to many 
 of his admirers on this side of the Atlantic that he had been labor- 
 ing for years on a work designed to be the magnum opus of his life 
 — "The Geology of Scotland." But his untimely death, it was 
 supposed, had cut short his labors, and left the work in a state so 
 fragmentary that his literary executors would not venture to publish 
 it. The impression was a correct one, as related to the design of 
 the author, in its magnitude and completeness. But the present 
 volume supplies, to general readers, what the proposed work would 
 have done for the scientific world. It gives the geological history 
 of Scotland — and, with Scotland, of the world — in language intel- 
 ligible to all, and with an affluence of anecdote, and incident, and 
 literary allusion, in which Hugh Miller was without an equal 
 among the scientific writers of our century. It gives precisely what
 
 II PREFACE. 
 
 a multitude of readers in this country have been longing to find — 
 a rational account of the manner in which all the strata of the 
 earth's crust have been formed, from the foundation of unstratified 
 granite and gneiss to the alluvial deposits of its surface. Scotland is 
 literally taken to pieces, like a house of many stories; and one looks 
 on the processes of the Divine Architect, as he would on the work 
 of a human builder. The hypotheses (for they can be regarded 
 only as such) are original, and curious, and plausible. Some read- 
 ers may doubt their accuracj', but none will question the eminent 
 ability with which they are developed. The volume will add to the 
 reputation of the author, and the popularity of his writings; and 
 will aid many, who have a slight acquaintance with geological science, 
 to form habits of practical observation in their country rambles. 
 
 The American Publishers have given the title of "Descriptive 
 Sketches" to sundry papers which Mrs. Miller has selected from 
 unpublished manuscripts of her husband, and to which, with charac- 
 teristic modesty, she gave the simple name of "Appendix." They 
 regarded these papers as an important part of the volume, and de- 
 manding, from their Intrinsic merits, a distinctive title. 
 
 Boston, April, 1859.
 
 CONTENTS. 
 
 Introbuctort Resume of the Progress of Geological Sci- 
 ence, 11 
 
 LECTURE FIRST. 
 
 Junction of Geologic and Human History — Scottish History of Modern Date — 
 The two periods previous to the Roman Invasion; the Stone Age and the 
 Bronze Age — Geological Deposits of these Pre-historic Periods — The Aborig- 
 inal Woods of Scotland — Scotch Mosses consequences of the Coman Invasion 
 
 — How Formed — Deposits, Natural and Artificial, found under them — The 
 Sand Dunes of Scotland— Human Eemains and Works of Art found in them 
 
 — An Old Church Disinterred in 1835 on the Coast of Cornwall— Controversy 
 regarding it — Ancient Scotch Barony underlying the Sand— The Old and 
 New Coast Lines in Scotland — AVhere chiefly to be observed — Geology the 
 Science of Landscape — Scenery of the Old and New Coast Lines — Date of the 
 Change of Level from the Old to the New Coast Line uncertain — Beyond the 
 Historic, but within the Human Period —Evidences of the fact in remains 
 of Primitive Weapons and Ancient Boats —Changes of Level not rare events 
 to the Geologist — Some of these enumerated — The Boulder-Clay — Its preva- 
 lence in the Lowlands of Scotland — Indicated in the Scenery of the Country 
 --The Scratcliings on the Boulders accounted for— Produced by the Grating 
 of Icebergs when Scotland was submerged — Direction in which Icebergs 
 floated, from West to East— "Crag and Tail," the effect of it — Probable Cause 
 of the Westerly Direction of the Current, 37-83 
 
 I*
 
 VI CONTENTS. 
 
 LECTURE SECOND. 
 
 Problem first propounded to the Author in a Quarry— The Quarry's Two De- 
 posits, Old Red Sandstone and Boulder-Clay — The Boulder-Clay formed while 
 the Laud was subsiding — The Groovings and Tolishings of the Rocks in the 
 Lower Parts of the Country — Evidences of the fact — Sir Charles Lyell's Ob- 
 servations on the Canadian Lake District — Close of the Boulder-Clay Record 
 in Scotland —Its Continuance in England into the Pliocene Ages —The Trees 
 and Animals of the Pre-Glacial Periods — Elephants' Tusks found in Scotland 
 and England regarded as the Remains of Giants — Legends concerning them 
 — Marine Deposits beneath the Pre-Glacial Forests of England — Objections of 
 Theologians to the Geological Theory of the Antiquity of the Earth and of the 
 Human Race considered — Extent of the Glacial Period in Scotland — Evi- 
 dences of Glacial Action in Glencoe, Garelock, and the Highlands of Suther- 
 land—Scenery of Scotland owes its Characteristics to Glacial Action — The 
 Period of Elevation which succeeded the Period of Subsidence — Its Indica- 
 tions in Raised Beaches and Subsoils — How the Subsoils and Brick Clays 
 were formed — Their Economic Importance — Boulder-Stones interesting fea- 
 tures in the Landscape — Their prevalence in Scotland — The more remarka- 
 ble Ice-travelled Boulders described — Anecdotes of the "Travelled Stone of 
 Petty " and the Standing-Stone of Torribal — Elevation of the Land during 
 the Post-Tertiary Period which succeeded the Period of the Boulder-Clay — 
 The Alpine Plants of Scotland the Vegetable Aborigines of the Country — 
 Panoramic View of the Pleistocene and Post-Tertiary Periods — Modern Sci- 
 ence not adverse to the Development of the Imaginative Faculty, . 84-124 
 
 LECTURE THIRD. 
 
 The Poet Delta (Dr. Moir) — His Definition of Poetry —His Death — His Burial- 
 Place at Inveresk — Vision, Geological and Historical, of the surrounding 
 Country — What it is that imparts to Nature its Poetry — The Tertiary Forma- 
 tion in Scotland — In Geologic History all Ages contemporary — Amber the 
 Resin of the Pinui Succinifer— A Vegetable Production of the Middle Tertiary
 
 CONTENTS. Vn 
 
 Ages — Its Properties and Uses — The Masses of Insects inclosed in it — The 
 Structural Geology of Scotland — Its Trap Rock — The Scenery usually asso- 
 ciated with the Trap Rock — How Formed — The Cretaceous Period in Scot- 
 land — Its Productions — The Chalk Deposits — Death of Species dependent on 
 Laws different from those which determine the Death of Individuals — The 
 Two Great Infinites, 125-167 
 
 LECTURE FOURTH. 
 
 The Continuity of Existences twice broken in Geological History — The Three 
 Great Geological Divisions representative of three Independent orders of Ex- 
 istences — Origin of the Wealden in England — Its great Depth and high An- 
 tiquity — The question whether the Weald Formation belongs to the Creta- 
 ceous or the Oolite System determined in favor of the latter by its Position in 
 Scotland — Its Organisms, consisting of both Salt and Fresh Water Animals, 
 indicative of its Fluviatile Origin, but in proximity to the Ocean — The Out- 
 liers of the Weald in Morayshire — Their Organisms — The Sabbath- Stone oi 
 the Northumberland Coal-Pits — Origin of its Name — The Framework of 
 Scotland — The Conditions under which it may have been formed — The Lias 
 and the Oolite produced by the last great Upheaval of its Northern Mountains 
 — The Line of Elevation of the Lowland Counties — Localities of the Oolitic 
 Deposits of Scotland — Its Flora and Fauna — History of one of its Pine 
 Trees — Its Animal Organisms — A Walk into the Wilds of the Oolite Hills of 
 Sutherland 168-202 
 
 •LECTURE FIFTH. 
 
 The Lias of the Hill of Eathie — The Beauty of its shores — Its Deposits, how 
 formed — Their Animal Organisms indicative of successive Platforms of Exis- 
 tences — The Laws of Generation and of Death — The Triassic System — Its 
 Economic and Geographic Importance — Animal Footprints, but no Fossil 
 Organisms, found in it — The Science of Ichnologij originated in this fact — 
 Illustrated by the appearance of the Compensation Pond, near Edinburgh,
 
 Vlir CONTENTS- 
 
 in 1842— The Phenomena indicated by the Foot-prints in theTriassic System 
 — The Triassic and Permian Systems once regarded as one, under the name of 
 the New Ked Sandstone — The Coal Measures in Scotland next in Order of 
 Succession to the Triassic System — Differences in the Organisms of the two 
 Systems — Extent of the Coal Measures of Scotland — Their Scenic Peculiari- 
 ties—Ancient Flora of the Carboniferous Period — Its Fauna — Its Reptiles 
 and Reptile Fishes — The other Organisms of the Period — Great Depth ol 
 the System — The Processes by which, during countless Ages, it had been 
 formed, 203-248 
 
 LECTURE SIXTH. 
 
 Eemote Antiquity of the Old Red Sandstone — Suggestive of the vast Tracts of 
 Time with which the Geologist has to deal — Its great Depth and Extent in 
 Scotland and England — Peculiarity of its Scenery — Reflection on first dis- 
 covering the Outline of a Fragment of the Asterolepis traced on one of its 
 Rocks— Consists of Three Distinct Formations — Their Vegetable Organisms 
 — The Caithness Flagstones, how formed — The Fauna of the Old Red Sand- 
 stone — The Pterichthys of the Upper or Newest Formation — The Cephalaspis 
 of the Lower Formation — The Middle Formation the most abundant in Or* 
 ganic Remains — Destruction of Animal Life in the Formation sudden and 
 violent — The Asterolepis and Coccosteus — The Silurian the Oldest of the 
 Geologic Systems — That in which Animal and Vegetable Life had their 
 earliest beginnings — The Theologians and Geologists on the Antiquity of the 
 Globe — Extent of the Silurian System in Scotland — The Classic Scenery of 
 the country situated on it — Comparatively Poor in Animal and Vegetable 
 Organisms — The Unfossiliferous Primary Rocks of Scotland — Its Highland 
 Scenery formed of them — Description of Glencoe — Other Highland Scenery 
 glanced at — Probable Depth of the Primary Stratified Rocks of Scotland — 
 How deposited — Speculations of Philosophers regarding the Processes to which 
 the Earth owes its present Form — The Author's views on the subject, 249-298
 
 CONTENTS OF DESCRIPTIVE SKETCHES. 
 
 Page 
 
 ACCITMULATIONS OF SHELLS, PHENOMENA EXPLANATORY OV . . 340 
 
 AMMONITES OP THE NORTHERN LIAS ..... 348 
 
 ASTREA OF THE OOLITE, SUTHERLAND ..... 309 
 
 BELEMNITE9 OP THE NORTHERN LIAS ..... 349 
 
 BONE-BED, RECENT, IN THE FORMING ..... 302 
 
 BRAAMBURT, QUARRT OP, UPPER OOLITE, SUTHERLAND . . 316 
 
 BREWSTER, SIR DAVID, ON THE CUTTLE-FISH AND BELEMNITE . . 372 
 
 BRORA COAL FIELD OTHER THAN THE TRUE COAL-MEASURES . 311 
 
 BRORA PEAT-MOSSES OP THE OOLITE ...... 315 
 
 CAUTION TO GEOLOGISTS ON THE FINDING OF REMAINS . . 342 
 
 CLAY-BED OF THE NORTHERN SUTOR, LESSON TO YOUNG GEOLOGISTS . 336 
 
 CONGENERS OF THE CUTTLE-FISH, BELEMNITE, ETC. . . . 357 
 
 COPROLITES OP THE LIAS ... . . . . .365 
 
 CROMARTY ......... 328 
 
 CROMARTY, CAVES OF, OR THE ART OF SEEING OVER THE ART OF THEO- 
 RIZING ......... 329 
 
 CROMARTY SUTOR, LINE OF ...... . 335 
 
 CUTTLE-FISH ......... 349 
 
 DIPTERUS MACROLEPIDOTUS, ABUNDANT IN THE BANNISKIBK OLD RED 
 
 OF CAITHNESS ........ 304 
 
 EATHIE, INTRUSIVE DIKES OF . . . . . . . 366 
 
 ECONOMIC GEOLOGY, LONDON MUSEUM OF .... 313 
 
 FOSSIL-WOOD OF THE OOLITE AT HELMSDALE, SUTHERLAND . . 306
 
 X CONTENTS. 
 
 6AKOID SCALES AND BAYS ....... 301 
 
 GLACIAL APPEARANCES AT NIGG AND LOGIB .... 338 
 
 OLACIEBS AND MOKAINES OF SUTHERLAND .... 319 
 
 GRANITIC GNEISS AND SANDSTONE, WITH THE CONDITIONS OP THEIR 
 
 UPHEAVAL ........ 345 
 
 LEVEL STEPPES OP RUSSIA, AND THEORY OP MORAINES . . . 324 
 
 SEPTARIA, OR CEMENT-STONES, OP THE LIAS .... 347 
 
 TEREBKATULA, CONTEMPORARY AND EXTINCT TYPES OP THE LIPE OP 370 
 
 TRAVELLED BOULDERS NOT ASSOCIATED WITH CLAY . . . 344 
 
 TYPES, RECENT, OP FOSSILS ....... 310 
 
 UNDERLYING CLAY ON LEVEL UOOBS, BSMABKS ON . . . 343 
 
 THEOBY OP THE OCEAN'S LEVEL ...... 375 
 
 CHAIN OP CAUSES ........ 383 
 
 RECENT GEOLOGICAL DISCOVEBIES ...... 409 
 
 SIB BODEBICK MUBCHISON ON THE RECENT GEOLOGICAL DISCOVEBIEi 
 
 IN MOBAYSHIBB ........ 419
 
 INTRODUCTORY RESUME 
 
 PROGRESS OF GEOLOGICAL SCIENCE. 
 
 The following Lectures, with " The Cruise of the Betsey," 
 and " Rambles of a Greologist," are all that remain of what 
 Hugh Miller once designed to be his Maximum Opus, — The 
 Geology of Scotland. It is well, however, that his ma- 
 terials have been so left that they can be presented to the 
 public in a shape perfectly readable ; furnishing two volumes, 
 each of which, it is hoped, will be found to possess in itself a 
 uniform and intrinsic interest — differing in matter and man- 
 ner as much as they do in the form in which they have found 
 an embodiment. That form is simply the one naturally arising 
 out of the circumstances of the Author's life as they occurred, 
 instead of the more artificial plan designed by himself, in which 
 these circumstances would probably, more or less, if not alto- 
 gether, have disappeared. Yet it may weU be doubted whether
 
 12 INTRODUCTORY RESUME: 
 
 the natural method does not possess a" charm which any more 
 formal arrangement would have wanted. Every one must be 
 struck with the freshness, buoyancy, and vigor displayed in the 
 "Summer Rambles;" — qualities more apparent in these than 
 even in his more labored Autobiography, of which they are, 
 indeed, but a sort of unintentional continuation. They were 
 the spontaneous utterances of a mind set free from an occu- 
 pation never very congenial, — that of writing compulsory 
 articles for a newspaper, — to find refreshment amid the fami- 
 liar haunts in which it delighted, and to seize, with a grasp 
 easy, yet powerful, on the recreation of a favorite science, as 
 the artist seizes on the pencil from which he has been sepa- 
 rated for a time, or the musician on some instrument much 
 loved and long lost, which he well knows will, as it yields to 
 him its old music, restore vigor and harmony to his entire 
 being. My dear husband did, indeed, bring to his science all 
 that fondness, while he found in it much of that kind of 
 enjoyment, which we are wont to associate exclusively with the 
 love of art. 
 
 The delivery of these Lectures may not yet have passed 
 quite away from the recollection of the Edinburgh public. 
 They excited unusual interest, and awakened unusual atten- 
 tion, in a city where interest in scientific matters, and attend- 
 ance upon lectures of a very superior order, are affairs of 
 every-day occurrence. Rarely have I seen an audience so
 
 PROGRESS OF GEOLOGICAL SCIENCE. 13 
 
 profoundly absorbed. And at the conclusion of the whole, 
 when the lecturer's success had been triumphantly established 
 (for it must be remembered that lecturing was to him an 
 experiment made late in life), I ventured to urge the propriety 
 of having the series published before the general interest had 
 begun to subside. His reply was, " I cannot afford it. I have 
 given so many of my best facts and broadest ideas, — so much, 
 indeed, of what would be required to lighten the drier details 
 in my ' Geology of Scotland,' — that it would never do to pub- 
 lish these Lectures by themselves." It will thus be seen that 
 they veritably gather into one luminous centre the best por- 
 tions of his contemplated work, gai'nering very much of what 
 was most vivid in painting and original in conception, — of 
 that which has now, alas ! glided, with himself, into those 
 silent shades where dwell the souls of the departed, with the 
 halo of past thought hovering dimly round them, waiting for 
 that new impulse from the Divine Spirit which is to quicken 
 them into an intenser and higher unity. 
 
 I have been led to indulge the hope that this work will be 
 found useful in giving to elementary Geology a greater attrac- 
 tiveness in the eyes of the student than it has hitherto pos- 
 sessed. It was characteristic of the mind of its author, that he 
 valued words, and even facts, as only subservient to the high 
 powers of reason and imagination. It is to be regretted that 
 many introductory works, especially those for the use of 
 
 2
 
 14 INTRODUCTORY RESUME: 
 
 schools, should be so crammed with scientific terms, and facts 
 hard packed, and not always well chosen, that they are fitted 
 to remind us of the dragon's teeth sown by Jason, which sprung 
 nip into armed men, — being much more likely to repel, than 
 to allure into the temple of science. One might, indeed, as 
 well attempt to gain an acquaintance with English literature 
 solely from the study of Johnson's Dictionary, as to acquire an 
 insight into the nature of Geology from puzzling over such 
 books. But, viewed in the light of a naind which had ap- 
 proached the subject by quite another pathway, all unconscious, 
 in its outset, of the gatherings and recordings of others, and 
 which never made a single step of progression in which it was 
 not guided by the light of its own genius and the inspiration 
 of nature, it may be regarded by beginners in another aspect, 
 — one very different from that in which Wordsworth looked 
 upon it when he thanked Heaven that the covert nooks of 
 nature reported not of the geologist's hands, — " the man who 
 classed his splinter by some barbarous name, and hurried on." 
 At that time the poet must have seen but the cold, hard profile 
 of the man, instead of the broad, beaming, full-orbed glance 
 which he may have cast over the wondrous aeons of the past 
 eternity. 
 
 To meet any difficulties arising from misconception, it may 
 be proper to glance rapidly at what has been accomphshed in 
 geological research within the last two years. The reader will
 
 PROGRESS OF GEOLOGICAL SCIENCE. 15 
 
 thus avoid the painful impression tliat there are any suppressecj 
 facts of recent date which clash with the theories of the suc- 
 ceeding Lectures, destroying their value and impairing their 
 unity. And it may be jvell to remind him that there are two 
 schools of Geology, quite at one in their willingness to bring 
 all theories to the test of actual discovery, but widely diffei'ing 
 in their leanings as to the mode in which, a priori, they would 
 wish the facts brought to light to be viewed. The one, as 
 expounded in the following Lectures, delights in the unfolding 
 of a great plan, having its original in the Divine Mind, which 
 has gradually fitted the earth to be the habitation of intelligent 
 beings, and has introduced upon the stage of time organism 
 after organism, rising in dignity, until all have found their 
 completion in the human nature, which, in its turn, is a 
 prophecy of the spiritual and Divine. This may be said to 
 be the true development hypothesis, in opposition to the false 
 and puerile one, which has been discai-ded by all geologists 
 worthy of the name, of whatsoever side. The other school 
 holds the opinion — though, perhaps, not very decidedly — 
 that all things have been from the beginning as they are now ; 
 and that if evidence at the present moment leans to the side of 
 a gradual progress and a serial development, it is because so 
 much remains undiscovered ; the hiatus, wherever it occurs, 
 being always in our own knowledge, and not in the actual state 
 of things. The next score of years will probably bring the 
 matter to a pretty fair decision ; for it seems impossible that.
 
 16 INTRODUCTORY RESUME: 
 
 if so many able workers continue to be employed as industri- 
 ously as now in the same field, the remains of man and the 
 higher mammals will not be found to be of all periods, if at all 
 periods they existed. In the meantin^, it is well to know the 
 actual point to which discovery has conducted us ; and this I 
 have taken every pains most carefuUy to ascertain. 
 
 The Upper Ludlow rocks — the uppermost of the Silurians 
 — continue to be the lowest point at which fish are found. 
 Up to that period, — during the vast ages of the Cambrian, 
 where only the faintest traces of animal life have been de- 
 tected^ in the shape of annelides or sand-boring worms, — 
 throughout the whole range of the Silurians, where shell-fish 
 and crustaceans, with inferior forms of life abounded, — no 
 traces of fish, the lowest vertebrate existences until the 
 latest formed beds of the Upper Silurian, have yet appeared. 
 There are now six genera of fish ranked as Upper Silurian, — 
 Auchenaspis, Cephalaspis, Pteraspis, Plectrodus, Onchus Mur- 
 chisoni, and Sphagodus. The two latter — Onchus Murchisoni 
 and Sphagodus — are represented by bony defences, such as 
 are possessed by placoid fishes of the present day. Sir Rod- 
 erick Murchison at one time entertained the idea of placing 
 the Ludlow bone-bed at the base of the Old Red Sandstone ; 
 but its fish having been found decidedly associated with Silu- 
 rian organisms, this idea has been abandoned. 
 
 1 See the lately published edition of Sir Roderick Murchison's " Siluria," 
 chap. ii. p. 26.
 
 PROGRESS OF GEOLOGICAL SCIENCE. 17 
 
 The next point to which public attention has been specially 
 directed, is the discovery of mammals lower than they had 
 formerly appeared. Considerable misconception has arisen on 
 this head. The Middjj^ Purbeck beds, recently explored by 
 Mr. Beckles, in which various small mammals were found, 
 occur considerably farther up than the Stonesfield slates, in 
 which the first quadruped was detected so far back as 1818. 
 But this discovery involves no theoretical change, inasmuch as 
 all the mammalian remains of the Middle Purbecks consist of 
 small marsupials and insectivora, varying in size from a rat to 
 a hedgehog, with one or two doubtful species, not yet proved 
 to be otherwise. The living analogue of one very interesting 
 genus is the kangaroo rat, which inhabits the prairies and 
 scrub-jungles of Australia, feeding on plants and scratched-up 
 roots. Between the English Stonesfield or Great Oolite, in 
 which, many years ago, four species of these small mammals 
 were known to exist, and the Middle Purbeck, quarried by 
 Mr. Beckles, in which fourteen species are now found, there 
 intervene the Oxford Clay, Coral Rag, Kimmeridge Clay, 
 Portland Oolite, and Lower Purbeck Oolite ; and then, after 
 the Middle Purbeck, there occurs a great hiatus throughout 
 the Weald, Green Sand, Gault, and Chalk, wherein no quad- 
 rupedal remains have been found ; until at lengtli we are 
 introduced, in the Tertiary, to the dawn of the grand mamma- 
 lian peribd; so that nothing has occurred in this department 
 to occasion any revolution in the ideas of those who, with my 
 
 2*
 
 18 IN^TRODUCTORY RESUME: 
 
 husband, consider a succession and development of type to be 
 the one great fixed law of geological science. The reader will 
 see that in the end of Lecture Thii'd such remains as have 
 been found lower than the Tertiary are expressly recognized 
 and excepted. " Save," says the author, " in the dwarf and 
 inferior forms of the marsupials and insectivora, not any of the 
 honest mammals have yet appeared." 
 
 But while attaching no importance to the discoveries in the 
 Middle Purbeck, except in regard of more ample numerical 
 development, it is necessary to admit the evidence of marsu- 
 pials having been found lower than the Stonesfield or Great 
 Oolite ; even so far back as the Upper Trias, the Keuper 
 Sandstone of Germany, which lies at the base of the Lias. I 
 must be permitted, on this point, to quote the authority of Sir 
 Roderick Murchison, as one of the safest and most cautious 
 exponents of geological fact. " In that deposit," says he, 
 referring to the Keuper Sandstone of Wurtemberg, " the 
 relics of a solitary small marsupial mammal have been ex- 
 humed, which its discoverer, Plieninger, has named Microlestes 
 Antiquus. Again, Dr. Ebenezer Emmons, the well-known 
 geologist, of Albany, in the United States, has described, from 
 the lower beds of the Chatham Secondary Coal-field, North 
 Carolina (of the same age as those of Virginia, and probably 
 of the "Wurtemberg Keuper), the jaws of another minute mam- 
 mal, which he calls Dromotherium Sylvestre. Lastly, while I
 
 PROGRESS OF GEOLOGICAL SCIENCE. 19 
 
 write, Mr. C. Moore has detected in an agglomerate which 
 fills the fissures of the carboniferous limestone near Frome, 
 Somersetshire, the teeth of marsupial mammals, one of which 
 he considers to be clos^y related to the Microlestes Antiquus 
 of Germany, and Professor Owen confirms the fact. From 
 that coincidence, and also from the association with other ani- 
 mal remains, — the Placodus (a reptile of the Muschelkalk), 
 and certain mollusca, — Mr Moore beheves that these patches 
 represent the Ken per of Germany. If this view should be 
 sustained, this author, who has already made remarkable 
 additions to our acquaintance with the organic remains of the 
 OoUtic rocks and the Lias, will have had the merit of having 
 discovered the first traces of mammalia in any British stratum 
 below the Stonesfield slates." . . . . " Let me entreat," 
 says Sir Roderick, in a passage occurring shortly after that we 
 have quoted, " Let me entreat the reader not to be led by the 
 reasoning of the ablest physiologist, or by an appeal to minute 
 structural afiinities, to impugn the clear and exact facts of a 
 succession from lower to higher grades of life in each forma- 
 tion. Let no one imagine that because the bony characters in 
 the jaw and teeth of the Plagiaulax of the Purbeck strata are 
 such as the comparative anatomist might have expected to find 
 among existing marsupials, and that the animal is, therefore, 
 far removed from the embryonic archetype, such an argument 
 disturbs the order of succession of classes, as seen in the crust 
 of the earth." So far from disturbing the order of succession,
 
 20 . INTRODUCTORY RESUME: 
 
 it is, we conceive, of exceeding interest to find the Mesozoic 
 period marked in its commencement, as it most probably will 
 be found to be, by the introduction of a form of being so 
 entirely different from any that preceded it. It seems to us to 
 bring the true development hypothesis into a clearer and more 
 harmonious unity. The great period during which the little 
 annelide or sand-boring worm was the sole tenant of this wide 
 earth, — its first inhabitant after the primeval void, — has 
 passed. The seon of the Mollusc and the Crustacean follows. 
 At its close appear the first fishes, very scanty in point of 
 numbers and of species, but multiplying into many genera, 
 and swarming in countless myriads, as the Devonian ages wear 
 on. Again, towards the termination of the latter, appear the 
 first reptiles, which, during the Carboniferous and Permian 
 eras, reign as the master-existences of creation. But Palteozic 
 or ancient life passes away, and the Mesozoic or Middle period 
 is marked not only by countless forms, all specifically, and 
 many of them generically, new, but by another wholly un- 
 known, either as genus or species, during all the past. The 
 little marsupials and insectivora appear "perfect after their 
 kind," and yet only the harbingers of the great mammalian 
 period which is yet to come. In the volume of Creation, as 
 in that of Providence, God's designs are wrapt in profound 
 mystery until their completion. And yet in each it would 
 appear that He sends a prophetic messenger to prepare the
 
 PROGRESS OF GEOLOGICAL SCIENCE. 21 
 
 way, in which the clear-sighted eye, intent to read His pur 
 poses, may discern some sign of the approaching future. 
 
 Before we proceed, we must here, on behalf of the un- 
 learned, and therefore the more easily misled, most humbly 
 venture to reclaim against the use, on the part of men of the 
 very highest standing, of the loose and dubious phi-aseology in 
 which they sometimes indulge, and which serves greatly to 
 perplex, if not to lead to very erroneous conclusions. 
 
 " In respect to no one class of animals," says Professor 
 Owen, in his last Address to the British Association, " has 
 the manifestation of creative force been limited to one epoch 
 of time." This, translated into fact, can only mean that the 
 vertebrate type had its representative in the fish of the earliest 
 or Silurian epoch, and has continued to exist throughout all 
 the epochs which succeeded it. But the difficulty lies in the 
 translation ; for, at first sight, the conclusion is inevitable, to 
 the general reader, that not only the lowest class of vertebrate 
 existence, but also man and the higher mammals, had been 
 found from the beginning, and that the highest and the lowest 
 forms of being were at all periods contemporary. No one, 
 surely, would have a right to make such a prodigious stride in 
 the line of inference, on the presumption of supposed evidence 
 yet to come. Again, Sir Charles Lyell, in his supplement to 
 the fifth edition of his " Elementary Geology," says, in speak-
 
 22 INTRODUCTORY RESUME: 
 
 ing of these same Purbeck beds quarried by Mr. Beckle?, 
 " They aiford the first positive proof, as yet obtained, of the 
 coexistence of a varied fauna of the highest class of vertebrata 
 with that ample development of reptile life which marks the 
 periods from the Trias to the Lower Cretaceous inclusive." 
 Are marsupials and insectivora the highest class of vertebrata ? 
 Where, then, do the great placental mammals — where does 
 man himself — take rank ? 
 
 It were surely to be desired that some stricter and more 
 invariable form of phraseology were adopted, either in accord- 
 ance with the divisions of Cuvier, or some analogous system, 
 adherence to which would be clearly defined and understood. 
 "Why should not the Avords class, order, type, have as invariable 
 a meaning as genera and species, which, having an application 
 more limited, are seldom mistaken ? "We are aware that such 
 terms are often used by the learned in an indefinite and trans- 
 latable sense, just as to the learned in languages it may be a 
 matter of indifference whether the written characters which 
 convey information to them be Roman, Hebrew, or Chinese. 
 But it should be remembered that there is a large class outside 
 which seeks to be addressed in a plain vernacular — which 
 asks, first of all, definiteness in the use of terms to which prob- 
 ably they have already sought to attach some fixed sense ; and 
 that it is not well to unsliip the rudder of their thought, and 
 eend them back to sea as:ain.
 
 PROGRESS OF GEOLOGICAL SCIENCE. Z-i 
 
 The next point which demands attention in our short resume 
 is that great break between the Permian and Triassic systems, 
 across which, as stated in the following pages, not a single 
 species has found its way. Much attention has been given to 
 the great Hallstad or St. Cassian beds, which lie on the north- 
 em and southern declivities of the Austrian Alps. These beds 
 belong to the Upper Trias, and they contain more genera com- 
 mon to PaliEozoic and newer rocks than were formerly known. 
 There are ten genera peculiarly Triassic, ten common to older, 
 and ten to newer strata. Among these, the most remarkable 
 is the Orthoceras, which was before held to be altogether 
 Palaeozoic, but is here found associated with the Ammonites 
 and Belemnites of the secondary period.^ The appearance of 
 this, ^vith a few other familiar forms, serves, in our imagina- 
 tion at least, to lessen the distance, and, in some small measure, 
 to bridge over the chasm, between Palfeozoic and Secondary 
 life. And yet, considering the vast change w'hich then passed 
 over our planet, — that all specific forms died out, while new 
 ones came to occupy their room, — the discovery of a few more 
 connecting generic links in the rudimentary shell-alphabet, 
 which serve but to show that in all changes the God of the 
 past is likewise the God of the present, no more affects in 
 reality this one great revolution, the completeness of which is 
 marked by the very difficulty of finding, amid so much new 
 
 1 See Sir Charles Lyell's " Supplement " for corroboration of the forego 
 ing statements.
 
 24 INTRODUCTORY RESUME*. 
 
 and redundant life, a single identical specific variety, than the 
 well-known existence of the Terebratula in the earliest, as well 
 as in the existing seas, can efface the great ground-plan of 
 successive geological eras.^ Nor does it explain the matter to 
 say that geographical changes took place, bringing with them 
 the denizens of different climates, and adapted for different 
 modes of life. The same Almighty Power which 7iow pro- 
 vides habitats and conditions suitable for the wants of his 
 creatures, would, doubtless, have done so during all the past. 
 Geographical changes are at all times indissolubly connected 
 with changes in the conditions of being ; and they serve, in so 
 far, to explain the rule in the stated order of geological events, 
 when a due proportion of extinct and of novel forms are found 
 coexistent. But how can they explain the exception ? A 
 singular effect must have a singular cause. And when we 
 find that there were changes relating to the world's inhabitants 
 altogether singular and abnormal in their revolutionary char- 
 acter, we must infer that the medial causes of which the Crea- 
 tor made use were of a singular and abnormal character also. 
 On this head the best-informed ought to speak with extreme 
 diffidence. We can but imagine that there may have been a 
 long, iinmeasui"able period, during which a subsidence, so to 
 speak, took place in the creative encn'gy, and during which all 
 specific forms, one after another, died out, — the hill of a dying 
 
 1 See Terelrratula, pa^e HI. The extinct Terebratula is now called 
 Rhynconella.
 
 PROGRESS OP GEOLOGICAL SCIENCE. 25 
 
 creation, — and then a renewal of the impulsive force from 
 that Divine Spirit which brooded over the face of the earliest 
 chaotic deep, producing geographical changes, more or less 
 rapid, which should prepare the way for the next stage in our 
 planetary existence, — its new framework, and its fresh burden 
 of vital beings. 
 
 The other great break in the continuity of fossils, which 
 occurs between the Chalk and the Tertiary, seems to be very 
 much in the same condition with that of which we have just 
 spoken. New connecting genera have been discovered, but 
 still not a single identical species. Jukes, in his " Manual," 
 published at the end of last year, says : " Near Maestricht, in 
 Holland, the chalk, with flint, is covered by a kind of chalky 
 rock, with gray flints, over which are loose, yellowish lime- 
 stones, sometimes almost made up of fossils,'' Similar beds 
 also occur at Saxoe in Denmark. Together with true creta- 
 ceous fossils, such as pecten and quadricostatus, these beds 
 contain species of the genera Voluta, Fasciolaria, Cyprea, 
 Oliva, etc., etc., several of which genera are also found else- 
 where in the Tertiary rocks. ^ 
 
 Sir Roderick Murchison's late explorations in the Highlands 
 — although, of course, local in their character — have made a 
 
 1 A doubt has, nevertheless, been expressed whether these are not bro- 
 ken-up Tertiaries. 
 
 3
 
 26 INTRODUCTORY RESUME: 
 
 considerable change in the Geology of Scotland. The 
 next edition of the "Old Red Sandstone" will be the most fit- 
 ting place to speak of these at length ; and I have some reason 
 to believe that Sir Roderick himself will then favor me with a 
 communication giving some account of them. Suffice it at 
 present to say, that the supposed Old Red Conglomerate of the 
 Western Highlands, as laid down in the year 1827 by Sir 
 Roderick himself, accompanied by Professor Sedgwick, and so 
 far acquiesced in by my husband, although he always wrote 
 doubtfully on the subject, has now been ascertained to be, not 
 Old Red, but Silurian. In Sir Roderick's last Address to the 
 British Association, he says: "Professor Sedgwick and him- 
 self had, thirty-one yeai's ago, ascertained an ascending order 
 from gneiss, covered by quartz rocks, with limestone, into 
 overlying quartzose, micaceous, and other crystalline rocks, 
 some of which have a gneissose character. They had also 
 observed what they supposed to be an associated formation of 
 red grit and sandstone ; but the exact relations of this to the 
 crystalline rocks was not ascertained, owing to bad weather. 
 In the meantime, they, as well as all subsequent geologists, had 
 erred in believing the great and lofty masses of purple and red 
 conglomerate of the western coast were of the same age as 
 those on the east, and therefore 'Old Red Sandstone.' . . . 
 Professor Nicol had suggested that the quartzites and lime- 
 stones might be the equivalent of the Carboniferous system of 
 the south of Scotland. Wholly dissenting from that hypoth-
 
 PROGRESS OF GEOLOGICAL SCIENCE. 27 
 
 esis, lit; (Sir Roderick) had urged Mr. Peach to avail himself 
 of his first leisure moments to reexamine the fossil-beds of 
 Durness and Assynt, and the result was the discovery of so 
 many forms of undoubted Lower Silurian characters (deter- 
 mined by Mr. Salter), that the question has been completely 
 set at rest — there being now no less than nineteen or twenty 
 species of M'Lurea, Murchisonia, Cephalita, and Orthoceras, 
 with an Orthis, etc., of which ten or eleven occur in the 
 Lower Silurian rocks of North Amex'ica." 
 
 This change would demand an entirely new map of the 
 Geology of Scotland ; for there is clearly ascertained to be an 
 ascending series from west to east, beginning with an older or 
 primitive gneiss, on which a Cambrian conglomerate, and over 
 that again a band containing the Silurian fossils, rest ; while a 
 younger gneiss occupies a portion of the central nucleus, hav- 
 ing the Old Red Sandstone series on the eastern side. A 
 change has likewise been made in the internal arrangements 
 of the Old Red, of which the next edition of my husband's 
 work on the subject will be the proper place to speak in detail. 
 In the meantime, I may just mention, that the Caithness and 
 Cromarty beds have been found to occupy, not the lowest, but 
 the central place, — the lowest being assigned to the Forfar- 
 shire beds, containing Cephalaspis, associated with Pteraspis, 
 an organism characteristically Silurian. That which bears 
 most upon the subject before us, is the now perfectly ascer-
 
 28 INTRODUCTORY Rt!S0ME : 
 
 tained imprint of the footsteps of large reptiles in the Elgin or 
 uppermost formation of the Old Red. A shade of doubt had 
 rested upon the discovery made many years ago by Mr. Pat- 
 rick Dulf, of the Telerpeton Elginense, not as to the real nature 
 of the fossil, which is indisputably a small lizard, but as to 
 whether the stratum in which it was found belonged to the 
 Old Red, or to the formation immediately above it. It will be 
 observed, however, that the existence of reptiles in the Old 
 Red did not rest altogether upon this, because the footprints 
 of large animals of the same class had been ascertained in the 
 United States of America. I cannot but conceive, therefore, 
 that Mr. Duff, in a recent letter or paper read in Elgin, and 
 published in the Elgin and Morayshire Courier, makes too 
 nuch of the recent discoveries in his neighboi'hood, Avhen he 
 asserts that the Old Red Sandstone had been hitherto consid- 
 ered exclusively a Jish formation, and that the appearance of 
 reptiles is altogether novel. " Now," says he, " that the Old 
 Red Sandstones of Moray have acquired some celebrity, it 
 may not be unprofitable to trace the different stages by which 
 the discovery was arrived at of reptilian remains in that very 
 ancient system, which till now was held to have been peopled by 
 no higher order of beings than fishes." Mr. Duff forgets that 
 in the programme, as it may be called, given by my husband, 
 of the introduction of different types of animal life, as ascer- 
 tained in his day, reptiles are made to occupy precisely the 
 position they do now. To refresh the memory of the reader,
 
 PROGRESS OF GEOLOGICAL SCIENCE. 
 
 29 
 
 1 shall here reproduce it, as given in the " Testimony of the 
 Rocks." At page 45 is this diagram : 
 
 Silurian. 
 Old Ked. 
 
 Carboniferous. 
 
 Fennian. 
 Triassic. 
 
 Oolitic. 
 Cretaceous. 
 
 Tertiary. 
 BeceuL. 
 
 Rad. Art. Mol. 
 Fishes. 
 
 Reptiles. 
 
 Birds. 
 3Iaininals. 
 
 ■ PI a. Mam. 
 
 ; Man. 
 
 Geologic [Had. Art Mol. Fish. Rep. Bird. Mam. Man.] arrangsmeDt 
 Cuvier's [Rad. Art. Mol. Fish. Rep. Bird. Mam. Man.] arrangement. 
 
 THE GENEALOGY OF ANIMALS 
 
 And on the following page occurs this comment : " In the 
 many-folded pages of the Old Red Sandstone, till we reach the 
 highest and last, there occur the remains of no other verte- 
 brates than those of this fourth class [fishes] ; but in its upper- 
 most deposits there appear traces of the third or reptilian class ; 
 and in passing upwards still, through the Carboniferous, Per- 
 mian, and Triassic systems, we find reptiles continuing the 
 master-existences of the time." And at page 104, express 
 allusion is made to the Telerpeton Elginense, with the doubt 
 
 3*
 
 30 INTRODUCTORY RESUME: 
 
 as to the nature of its locale very slightly touched upon.^ All 
 this Mr. DufF has forgotten, apparently ; and it appears like- 
 wise not to have come within his cognizance that Sir Charles 
 Lyell distinctly recognizes his Telerpeton, as well as the 
 American foot-prints, and assigns both their proper places, in 
 the last edition of his " Principles." Even in the edition before 
 the last of the " Siluria," almost the first thing that meets us, on 
 opening it at Chapter Tenth, which treats of the Old Red 
 Sandstone, is a print of the fossil skeleton of this same Teler- 
 peton Elginense — its true place assigned to it with quite as 
 much certainty as now ! These very singular lapses in mem- 
 ory seem not to be peculiar to Mr. DufF. I have seen it 
 stated, in an anonymous article published in a widely-circu- 
 lated journal,^ and in connection with the discovery of the 
 Elgin reptile foot-prints, that Hugh Miller considered the Old 
 Red Sandstone to have been a shoreless ocean without a tree!^ 
 — utterly ignoring the fact that he was himself the discoverer 
 of the first Old Red fossil-wood of a coniferous character, and 
 
 1 This doubt, I see by Sir Roderick Murchison's latest Address to the 
 British Association, is not yet entirely obviated. See page 422. 
 
 2 For this article, as an excellent specimen of its class, see page 409, 
 under the head "Recent Geological Discoveries;" and, in contradistinction 
 to it, the extract from Sir R. Murchison's Address ought to be carefully 
 studied. I myself had seen neither that extract, nor the recent " Siluria," 
 uotil after this short sketch was in type,— the references to the latter hav- 
 ing been introduced afterwards,— and it may be conceived with what feel- 
 ings of gratification I have perused Sir Roderick's repeated assurances of 
 adherence to the " Old Light." 
 
 ^ Sec Contra, p. 246.
 
 PROGRESS OF GEOLOGICAL SCIENCE. 31 
 
 that he thence expressly infers the then existence of vegetation 
 of a high order. Is it not enough to add to the store of 
 knowledge without attempting to undermine all that has gone 
 before ? Must the discovery of an additional reptile, a few 
 additional marsupials, be the signal for the immediate outcry, 
 " All is changed ; the former things have passed away ; all 
 things have become new ? " My husband was solicitous even 
 to the point of nervous anxiety to exclude from his writings 
 every particle of error, whether of facts, or of the conclusions 
 to be di-awn from them. Much rather would he never have 
 written at all than feel himself in any degree a false teacher. 
 " Truth first, come what may afterwards," was his invariable 
 motto. In the same spirit, God enabling me, I have been 
 desirous to carry on the publication of his posthumous writ- 
 ings. God forbid that one entrusted with such sacred guar- 
 dianship should seek to pervert or suppress a single truth, 
 actual or presumptive, even though its evidence were to over- 
 throw, in a single hour, all liis much-loved speculations — all 
 his reasonings, so long cogitated, so conscientiously wrought 
 ought. Yet I must confess that I was at first startled and 
 alarmed by rumors of changes and discoveries, which, I was 
 told, were to overturn at once the science of Geology as hith- 
 erto received, and all the evidences which had been drawn 
 from it in favor of revealed religion. Though well persuaded 
 that at all times, and by the most unexpected methods, the Most 
 High is able to assert Himself, the proneness of man to make
 
 32 INTRODUCTORY RESUME: 
 
 use of every unoccupied position in order to maintain his 
 independence of his Maker, seemed about to gain new vigor 
 by acquiring a fresh vantage-ground. The old cry of the 
 eternity of matter, and the " all things remain as they were 
 from the beginning until now," rung in my ears. God with 
 us, in the Avorld of science henceforth to be no more ! The 
 very evidences of His being seemed about to be removed into 
 a more distant and dimmer region, and a dreary swamp of 
 infidelity spread onwards and backwards throughout the past 
 eternity. 
 
 Without stopping to inquire whether — although the science 
 of Geology had been revolutionized — those fears were not 
 altogether exaggerated, it is enough at present to know, that, 
 as Geology has not been revolutionized, there is no need to 
 entertain the question. I trust I have at least succeeded in 
 furnishing the reader with such references — few and simple 
 when we once know where to find them — as may enable him 
 to decide upon this important matter for himself If I have 
 learned anything in the course of the investigations which I 
 have been endeavoring to make, it is to take nothing upon 
 credence, but to wait patiently for all the evidence which can 
 be brought to bear upon the subject befoi'e me ; and this, I 
 believe, is the only way to make any approximation to a cor- 
 rect opinion. In truth, the science of Geology is itself in that 
 condition, that no fact ought to be accepted as a basis for
 
 PROGRESS OF GEOLOGICAL SCIENCE. 33 
 
 reasoning of a solid kind, until it has run the round of" investi« 
 gation by the most competent authorities, and has stood the 
 test of time. It is peculiarly subject to the cry of Lo, here ! 
 and lo, there ! from false and imperfectly informed teachers ; 
 and I believe the men most thoi'oughly to be relied on are 
 those who are the slowest to theorize, the last to form a 
 judgment, and who require the largest amount of evidence 
 before that judgment is finally pronounced. 
 
 In addition to the inspection of my ever kind and generous 
 friend Mr. Symonds,^ I have submitted the following pages to 
 the reading of Mr. Geikie," of the Geological Survey, who has 
 here and there furnished a note. Of the amount and correct- 
 ness of his knowledge, acquired chiefly in the field and in the 
 course of his professional duties, my husband had formed the 
 highest opinion. Indeed, I believe he looked upon him as the 
 individual who would most probably be his successor as an 
 exponent of Scottish Geology. One who walks, on an aver- 
 age, twenty miles per day, and who has submitted nearly 
 every rood of the soil to the accurate inspection demanded by 
 the Survey, must be one whose opinion, in all that pertains to 
 Scottish Geology in especial, must be well worth the having. 
 I have to add an expression of most grateful thanks to Sir 
 
 1 The Rev. "W. S. Symonds, author of " Old Stones," " Stones of the 
 Valley," etc., and the compiler of the index to the recent edition of Sir R. 
 Murchison's " Siluria." 
 
 * Archibald Gleikie, Esq., author of "The Story of a Boulder."
 
 34 INTRODUCTORY RESUME: 
 
 Roderick Murchison, for his prompt attention to sundry appli* 
 cations which I was constrained to make to him. His letters 
 have been of the utmost importance in enabling me to perceive 
 clearly the alterations which have taken place in our Scottish 
 Geology, and the reasons for them. One feels instantaneously 
 the benefit of contact with a master-mind. A few sentences, 
 a few strokes of the pen, throw more light on the subject than 
 volumes from an inferior hand. 
 
 It remains now only to explain, that this course of Lec- 
 tures, as delivered before the Philosophical Institution, con- 
 sisted of eight, instead of six. Those now published are com- 
 plete, according to their limits, in all that relates to the facts, 
 literal or picturesque, of the subject ; and the last two of the 
 series will be found in " The Testimony of the Rocks," under 
 the heads of " Geology in its Bearing on the Two Theologies," 
 and " The Mosaic Vision of Creation." If it had been within 
 the contemplation of the author to pubUsh the six Lectures as 
 they now stand, these last two would have formed their natural 
 climax or peroration. And, accordingly, I entertained some 
 thought of i*epublishing them here, in order that the reader 
 might enjoy the advantage of having the whole under his eye 
 at once. But, as they are not in any way necessary to the 
 completion of the sense, and perhaps Geology, viewed simply 
 by itself, and in the light of a popular study, is as well freed 
 from extraneous matter, it was thought best, on the whole, to
 
 PROGRESS OF GEOLOGICAL SCIENCE. 35 
 
 refer the reader who wishes to see the eight discourses in their 
 original connection, to " Tlie Testimony of the Rocks." 
 
 I have, instead, added an Appendix of rather a novel char- 
 acter. In addition to the " Cruise of the Betsey," and " Ten 
 Thousand Miles over the Fossiliferous Deposits of Scotland," 
 there was left a volume of papers unpublished as a whole, 
 entitled " A Tour through the Northern Counties of Scotland." 
 They had, however, been largely drawn upon in various other 
 works ; but, scattered throughout were passages of more or less 
 value, w^hich I had not met with elsewhere ; and some such, 
 of the descriptive kind, I have culled and arranged at the end 
 of the Lectures : first, because I was loth that any original 
 observation from that mind which should never think again for 
 the instruction of others, should be lost, and also because many 
 of those passages were of a kind which might prove suggestive 
 to the student, and assist him in masoning upon those phenom- 
 ena of ordinary occurrence, without close observation of which 
 no one can ever arrive at a successful interpretation of nature. 
 If the reader should descry aught of repetition which has 
 escaped my notice, I must crave his indulgence, in considera- 
 tion of the very difficult and arduous task which God, in His 
 mysterious providence, has allotted me. To endeavoi* to do by 
 these writings as my husband himself would if he were yet 
 with us — to preserve the integrity of the text, and, in dealing 
 with what is new, to bring to bear upon it the same unswerv-
 
 36 INTRODUCTORY RESUME. 
 
 ing rectitude of purpose in valuing and accepting every iota of 
 truth, whether it can be explained or not, rejecting all that is 
 crude, and abhorring all that is false, — this has been my aim, 
 although, alas ! too conscious throughout of the comparative 
 feebleness of the powers brought to bear upon it. If, however, 
 the reader is led to inquire for himself, 1 trust he will find that 
 these powers, such as they are, have been used in no light or 
 frivolous spirit, but with a deep, and somewhat of an adequate, 
 sense of the vast importance of the subject. 
 
 L. M.
 
 LECTUKES ON GEOLOGY. 
 
 LECTURE FIRST. 
 
 Junction of Geologic and Human History — Scottish History of Modem Date 
 
 — The Two Periods previous to the Roman Invasion; the Stone Age and 
 the Bronze Age — Geological Deposits of these Pre-historic Periods — The 
 Aboriginal Woods of Scotland — Scotch Mosses consequences of the Roman 
 Invasion — How formed — Deposits, Natural and Artificial, found under them 
 
 — The Sand Dunes of Scotland — Human Remains and AVorks of Art found 
 in them — An Old Church Disinterred in 1835 on the Coast of Cornwall — 
 Controversy regarding it — Ancient Scotch Barony underlying the Sand — The 
 Old and New Coast Lines in Scotland — Where chiefly to be observed — Geol- 
 ogy the Science of Landscape — Scenery of the Old and New Coast Lines — 
 Date of the Change of Level from the Old to the New Coast Line uncertain — 
 Beyond the Historic, but within the Human Period — Evidences of the fact in 
 remains of Primitive AVeapons and Ancient Boats — Changes of Level not rare 
 events to the Geologist — Some of these enumerated — The Boulder-Clay — Its 
 prevalence in the Lowlands of Scotland — Indicated in the Scenery of the 
 Country — The Scratchiugs on the Boulders accounted for — Produced by the 
 grating of Icebergs when Scotland was submerged — Direction in which Ice- 
 bergs floated, from West to East — " Crag and Tail " the Effect of it — Probable 
 Cause of the Westerly Direction of the Current. 
 
 Int most of the countries of "Western Europe, Scotland 
 among the rest, geological history may be regarded as 
 ending where human history begins. The most ancient 
 portions of the one piece on to the most modern portions 
 of the other. But their line of junction is, if I may so 
 express myself, not an abrupt, but a shaded line ; so that, 
 on the one hand, the human period passes so entirely into 
 the geological, that we found our conclusions respecting
 
 38 LECTURES ON GEOLOGY. 
 
 the first human inhabitants rather on what they deemed 
 geologic than on the ordinary historic data; and, on the 
 other hand, some of the latter and lesser geologic changes 
 have taken place in periods comparatively so recent that, 
 in even our own country, we are able to catch a glimpse 
 of them in the first dawn of history proper, — that written 
 history in which man records the deeds of his fellows. 
 
 In Scotland the ordinary historic materials are of no 
 very ancient date. Tytler's History opens with the acces- 
 sion of Alexander III., in the middle of the thirteenth 
 century ; the Annals of Lord Hailes commence nearly two 
 centuries earlier, with the accession of Malcolm Canmore ; 
 there still exist among the muniments of Durham Cathe- 
 dral charters of the "gracious Duncan," written about 
 the year 1035 ; and it is held by Runic scholars that the 
 Anglo-Saxon inscription on the Ruthwell Cross may be 
 about two centuries earlier still. But from beyond this 
 comj^aratively modern period in Scotland no written docu- 
 ment has descended, or no native inscription decipherable 
 by the antiquary. A few votive tablets and altars, let- 
 tered by the legionaries of Agricola or Lollius Urbicus, 
 when engaged in laying down their long lines of wall, or 
 rearing their watch-towers, represent a still remoter period ; 
 and a few gi-aphic passages in the classic pages of Tacitus 
 throw a j^artial and fitful light on the forms and characters 
 of the warlike people against which the ramparts were 
 cast up, and for a time defended. But beyond this epoch, 
 to at least the historian of the merely literary type, or 
 to the antiquary of the purely documentary one, all is 
 darkness. " At one stride comes the dark." The period 
 is at once reached which we find so happily described by 
 Coleridge. " Antecedently to all history," says the poet, 
 " and long glimmering through it as a hazy tradition, there
 
 LECTURES ON GEOLOGY. 39 
 
 presents itself to our imagination an indefinite period, 
 dateless as eternity, — a state rather than a tiine. For 
 even the sense of succession is lost in the uniformity of 
 the stream." 
 
 It is, however, more than probable that the age of Agric- 
 ola holds but a midway place between the present time 
 and the time in which Scotland first became a scene of 
 human habitation. Two great periods had passed ere the 
 period of the Roman invasion, — that earliest period now 
 known to the antiquary as the " stone age^'' in w^hich the 
 metals were unknown, and to which the flint arrow-head 
 and the greenstone battle-axe belong; and that after 
 period known to the antiquary as the '■'■bronze age^'' in 
 which weapons of war and the chase were formed of a 
 mixture of copper and tin. Bronze had, in the era of 
 Agricola, been supplanted among the old Caledonians by 
 iron, as stone had at an earlier era been supplanted by 
 bronze ; and his legionaries were met in fight by men 
 armed, much after the manner of their descendants at 
 Sheriifmuir and Culloden, with broadsword and target. 
 And it is known that nearly a century and a half earlier, 
 when Ca3sar first crossed the Channel, the Britons used a 
 money made of iron. The two earlier periods of bronze 
 and stone had come to a close in the island ere the 
 commencement of the Christian era; and our evidence 
 regarding them is, as I have said, properly of a geologic 
 character. We read their history in what may be termed 
 iho. fossils of the antiquary. Man is peculiarly a tool-and- 
 weapon-making animal ; and his tools and weapons repre- 
 sent always the stage of civilization at which he has 
 arrived. First, stone is the material out of which he 
 fashions his implements. If we except that family of man 
 which preserved the aboriginal civilization, there seems
 
 40 LECTURES ON GEOLOGY. 
 
 never to have been a tribe or nation that liad not at one 
 time recourse to this most obvious of substances for their 
 tools and weapons. Then comes an age in which stone is 
 supplanted by the metals that occur in a native state, — 
 i. e. in a state of ductility in the rock, — such as copper, 
 silver, and gold. Of these, copper is by much the most 
 abundant ; and in all countries in which it has been era- 
 ployed for tools and weapons, means have been found by the 
 primitive woi'kers to harden it through an admixture of 
 other metals, such as zinc and tin. Last of all, the com- 
 paratively occult art of smelting iron is discovered, and 
 the further art of converting it into steel; and such is 
 its superiority in this form to every other metal employed 
 in the fabrication of implements, that it supplants every 
 other ; and the battle-axe and chisel of hardened copper 
 (bronze) are as certainly superseded by it as the chisel and 
 the battle-axe of stone had at an earlier period been super- 
 seded by the bronze.^ Now, it is truly wonderful how 
 thorouglily, for all general purposes, this scheme of classi- 
 fication, which we owe to the Danish antiquary Thomsen, 
 arranges into corresponding sections and groups the an- 
 
 1 In an interesting article on Ireland -which lately appeared in the 
 " Scotsman " newspajjer, I find it stated that for a very considerable dis- 
 tance, " between Lough Rca and Lough Derg, the river Shannon -was ford- 
 able at only one point, vk^hich of course formed the only medium of com- 
 munication between the natives of the two banks. They seem, however," 
 it is added, "to have met oftener for war than peace; and from this ford 
 a whole series of ancient warlike weapons was dug out. These weapons 
 arc now preserved in the fine collection of antiquities in the Museum of 
 the Itoyal Irish Academy in Dublin, and are partly bronze and partly 
 stone. Their position in the river bed told a curious talc, both historically 
 and geologically. The weapons of bronze were all found in the upper 
 stratum, and below them those of stone; showing, as antiquaries well 
 know, that an age of bronze followed not an age of gold, but an ago of 
 stone."
 
 LECTURES ON GEOLOGY. 41 
 
 tiquities of a country, and gives to it a legible history in 
 ages unrecorded by the chronicler. With the stone tools 
 or weapons there are found associated in our own country, 
 for instance, a certain style of sepulture, a certain type of 
 cranium, a certain form of human dwellings, a certain class 
 of personal ornaments, certain rude log-hollowed canoes, 
 undressed standing stones, and curiously-poised cromlechs. 
 The bronze tool or weapon has also its associated class of 
 antiquities, — massive ornaments of gold, boats built of 
 plank, and, as a modern shipwright would express himself, 
 copper-fastened, cinerary urns, — for it would seem that, 
 while in an earlier, as in a later age, our country-folk 
 buried their dead, in this middle period they committed 
 their bodies to the flames ; and, withal, evidences, in the 
 occasional productions of other countries, that commerce 
 had begun to break up the death-like stagnation which 
 characterized the earlier period, and to send through the 
 nations its circulating tides, feeble of pulse and slow, but 
 instinct, notwithstanding, with the first life of civilization. 
 And thus we reason on the same kind of unwritten data 
 regarding the human inhabitants of our country who lived 
 during these two early stages, as that on which we reason 
 regarding their contemporaries the extirpated animals, or 
 their jiredecessors the extinct ones. The interest which 
 attaches to human history thus conducted on what may 
 be termed the geologic plan is singularly great. No nation 
 during its stone period possesses a literature ; nor did any 
 nation, of at least Western Europe, possess a literature 
 during its bronze period. Of course, without letters there 
 can be no history ; and even if a detailed history of such 
 uncivilized nations did exist, what would be its value? 
 "Milton did not scruple to declare," says Hume, "that the 
 
 skirmishes of kites or crows as much merited a particular 
 
 4.*
 
 42 LECTURES ON GEOLOGY. 
 
 narrative as the confused transactions and battles of the 
 Saxon Heptarchy," But the subject rises at once in dig- 
 nity and importance when, contemplating an ancient people 
 through their remains, simply as men, we trace, step by 
 step, the influence and character of their beliefs, their 
 progress in the arts, the effects of invasion and conquest 
 on both their minds and bodies, and, in short, the broad 
 and general in their history, as opposed to the minute and 
 the particular. The story of a civilized people I would 
 fain stndy in the pages of their best and most philosophic 
 historians; whereas I would prefer acquainting myself 
 with that of a savage one archreologically and in its re- 
 mains. And I would appeal, in justification of the prefer- 
 ence, to the great superiority in interest and value of the 
 recently published " Pre-historic Annals of Scotland," by 
 our accomplished townsman, Mr, Daniel Wilson, over all 
 the diffuse narrative and tedious description of all the old 
 chroniclers that ever wore out life in cloister or cell. 
 
 What may be properly regarded as the geological de- 
 posits or formations of the two pre-historic periods in 
 Scotland, — the period of stone and the period of bronze, 
 — are morasses, sand dunes, old river estuaries, and that 
 marginal strip of flat land which intervenes between the 
 ancient and the existing coast lines. The remains of man 
 also occur, widely scattered all over the country, in a su- 
 pei-ficial layer, composed in some localities of the drift- 
 gravels, and in others of the boulder-clay; but to this 
 stratum they do not geologically belong: they lie at a 
 grave's depth, and have their place in it through the prev- 
 alence of that almost instinctive feeling which led the 
 patriarch of old to bury his dead out of his sight. Most 
 of the mistakes, however, which would antedate the exist- 
 ence of our species upon the earth, and make man con-
 
 LECTURES ON GEOLOGY. 43 
 
 temporary with the older extinct mammals, have resulted 
 from this ancient practice of inhumation, or from accidents 
 which have arisen out of it. 
 
 All our Scotch morasses seem to be of comparatively 
 modern origin. There are mosses in England, or at least 
 buried forests, as on the Norfolk coast, at Cromer and 
 Happisburgh, that are more ancient than the drift-clays 
 and gi'avels ; whereas, so far as is yet known, there are 
 none of our Scotch mosses that do not overlie the drift 
 formations ; and not a few of their number seem to have 
 been formed within even the historic ages. They are the 
 memorials of a period, spread over many centuries, which 
 began after Scotland had arisen out of the glacial ocean, 
 and presented, under a softening climate, nearly the exist- 
 ing area, but bore, in its continuous covering of forest, the 
 indubitable signs of a virgin country. It is remarked by 
 Humboldt, that all the earlier seats of civilization are bare 
 and treeless. "When, in passing from our thickly foliated 
 forests of oak, we cross," he says, " the Alps or the Pyr- 
 enees, and enter Italy or Spain, or when the traveller first 
 directs his eye to some of the African coasts of the Medi- 
 terranean, he may be easily led to adopt the erroneous 
 inference that absence of trees is a characteristic of the 
 warmer climates. But he forgets," it is added, "that 
 Southern Europe wore a different aspect when it was first 
 colonized by Pelasgian or Carthaginian settlers. He for- 
 gets, too, that an earlier civilization of the human race 
 sets bounds to the increase of forests ; and that nations, in 
 their change-loving spirit, gradually destroy the decora- 
 tions which rejoice our eye in the north, and which, more 
 than the records of history^ attest the yoiithfulness of our 
 civilization!'^ Some of my audience must be old enough 
 to remember the last of the great aboriginal woods of
 
 44 LECTURES ON GEOLOGY. 
 
 Scotland. It was only during the second war of the first 
 French Revolution, when the northern ports of Europe 
 were shut against Great Britain, that the native pine- 
 woods of Rothiemurchus and the upper reaches of the 
 Spey were cut down ; and as late as the year 1820, I 
 looked, in the upper recesses of Strathcarron, on the last 
 scattered remains of one of the most celebrated of the old 
 pine-forests of Ross-shire. Possibly some of the frag- 
 ments of the pine-forests which skirted the western shores 
 of Loch Maree may still exist ; though, when I last passed 
 through it, many years ago, the axe was busy among its 
 glades. It is known of some of our Scotch mosses, — the 
 deposits which testify geologically to this primitive state 
 of things when the country was forest-covered, — that 
 they date from the times of the Roman invasion, and were 
 consequences of it. The mark of the Roman axe — a 
 narrow, chisel-like tool — has been detected, in many in- 
 stances, on the lower tier of stumps over which the peat 
 has accumulated ; and in some cases the soi'ely rusted axe 
 itself has been found sticking in the buried tree. Among 
 the tangled debris of a prostrated forest the woodman fre- 
 quently mislays his tools, — a mishap to which the old 
 Romans seem to have been as subject as the men of a later 
 time ; and so the list of Roman utensils, coins, and arms, 
 found in the mosses of the south and midland parts of 
 Scotland, is in consequence a long one. " In Pousil Moss, 
 near Glasgow," says Rennie, in his "Essay on Peat Moss," 
 " a leathern bag containing about two hundred silver coins 
 of Rome was found ; in Dundaff Moor a number of simi- 
 lar coins were found; in Annan Moss, near the Roman 
 (Jauscway, a Roman ornament of pure gold was found ; a 
 Roman camp-kettle was found eight feet deep under a 
 moss on the estate of Ochtertyre; in Flanders Moss a
 
 LECTURES ON GEOLOGY. 45 
 
 Bimilar utensil was found ; a Roman jug was found in 
 Locher Moss, Dumfriesshire ; a pot and decanter of Ro- 
 man copper was found in a moss in Kirkmichael parish, in 
 the same county ; and two vessels of Roman bronze in the 
 Moss of Glenderhill, in Strathaven." And thus the list 
 runs on. It is not difficult to conceive how, in the circum- 
 stances, mosses come to be formed. Tlie Roman soldiers 
 cut down, in their march, wide avenues in the forests 
 through which they passed. The felled wood was left to 
 rot on the surface ; small streams were choked up in the 
 levels ; pools formed in the hollows ; the soil beneath, shut 
 up from the light and the air, became unfitted to produce 
 its former vegetation ; but a new order of plants, the thick 
 water-mosses, began to spring up ; one generation budded 
 and decayed over the ruins of another; and what had 
 been an overturned forest became in the course of years a 
 deep morass, — an unsightly but permanent monument of 
 the formidable invader. 
 
 Some of our other Scotch mosses seem to have owed 
 their origin to violent hurricanes ; — their under tier of 
 trunks, either turned up by the roots or broken across, lie 
 all one way. What may be termed their native fossils are 
 exceedingly curious. I have seen personal ornaments of 
 the stone period, chiefly beads of large size, made out of 
 a pink-colored carbonate of lime, which had been found in 
 the bed of gravel on which one of our Galwegian mosses 
 rested, and which intimated that the " stone period " had 
 commenced in the island ere this moss had begun to form. 
 We find the same fact borne out by the Black Moss on 
 the banks of the Etive, Argyleshire, where, under an accu- 
 mulation of eight feet of peat, there occur irregularly oval 
 pavements of stone, overlaid often by a layer of wood- 
 ashes, and surrounded by portions of hazel stakes, — the
 
 46 LECTURES ON GEOLOGY. 
 
 remains, apparently, of such jDrimitive huts as those in 
 which, according to Gibbon, the ancient Germans resided, 
 and which were, we are told, "of a circular figure, built 
 of rough timber, thatched with straw, and pierced at the 
 top, to leave a free passage for the smoke." Similar re- 
 mains, but ajjpai'ently of a still more ancient type, have 
 been laid open in Aberdeenshire ; and I find Mr. Wilson 
 stating, in his archaeological history, that on several occa- 
 sions, rude canoes, which had been hollowed out of single 
 logs of wood by the agency of fire, and evidently of the 
 " stone age," have been found in Lochar Moss, Dumfries- 
 shire, with ornamental tores and brass bowls, not less evi- 
 dently of the subsequent " bronze period." It is stated by 
 Dr. Boates, in his " Natural History," that in Ireland, the 
 furrows of what had been once ploughed fields have been 
 found underlying bogs, — in one instance at least (in Don- 
 egal), with the remains of an ancient plough, and the wat- 
 tles of a hedge six feet beneath the surface. In 1833 there 
 was discovered in Drumkilen bog, near the north-east 
 coast of the county of Donegal, an ancient house formed 
 of oak beams. Though only nine feet high, it consisted 
 of two stories, each about four feet in height. One side 
 of the building was entirely open, and a stone chisel was 
 found on the floor, — indicating that this ancient domicile 
 belonged to the stone period. Associated, too, with the 
 works of man of the earlier periods, we find in our mosses 
 equally suggestive remains of the extirpated^ and in some 
 cases of the extinct animals, such as gigantic skulls and 
 horns of the Jios Primigenhcs or native ox, and of the Cer- 
 vus Megaceros or Irish elk, with the skeletons of wolves, 
 of beavers, of wild horses, and of bears. There exists what 
 seems to be sufticient evidence that the two extinct ani- 
 mals named the Irish elk and native ox were contemporary
 
 LECTURES ON GEOLOGY. 47 
 
 with the primitive hunters of the stone peiiod : the cervi- 
 cal vertebrae of a native ox have been found deeply scarred 
 by a stone javelin, and the rib of an Irish elk perforated 
 by a stone arrow-head ; and it is known that some of the 
 extirpated animals, such as the wild horse, Avolf, and bea- 
 ver, continued to live among our forests down till a com- 
 paratively recent period.^ We find it stated by Hector 
 Boece, in his " History," that there "were beavers living 
 among our Highland glens even in his days, as late as the 
 year 1526; but there rests a shadow of doubt on the state- 
 ment. It is unquestionable, however, that the Gaelic 
 name of the creature, Lasleathin^ or broad-tail, still sur- 
 vives; and equally certain that when Baldwin, Arch- 
 bishop of Canterbury, journeyed into Wales towards the 
 close of the twelfth century, to incite the Welsh to join 
 in the Crusades, the beaver was engaged in building its 
 coffer domes and log-houses in the river Teivy, Cardigan- 
 shire. The wolf and wild horse maintained their place in 
 at least the northern pait of the island for several centu- 
 ries later. When in 1G18 Taylor, the water poet, visited 
 Scotland, he accompanied the " good lord of Mar " on one 
 of his great hunting expeditions among the Grampians; 
 and we find, from the amusing narrative of his journey, 
 that for the space of twelve days he saw neither house nor 
 corn-field, but " deer, wild horses, wolves, and such like 
 creatures." The wolf did not finally disappear fi-om among 
 our mountains until the year 1680, when the last of the 
 race was killed in Lochaber by that formidable Ewan 
 Cameron of Locliiel with whom Cromwell was content to 
 make peace after conquering all the rest of Scotland. 
 
 1 Many interestinf^ human remains have lately been disinterred from 
 the Severn drift and gravels near Tewkesburj', such as cinerary urns with 
 bones and ashes, and utensUs for carrying water, associated with antlers 
 of the red deer. — W. S. S.
 
 48 LECTURES ON GEOLOGY. 
 
 The sand dunes of the country — accumulations of sand 
 heaped over the soil by the winds, and in some cases, as in 
 the neighborhood of Stromness in Orkney, and near New 
 Quay on the coast of Cornwall, consolidated into a kind of 
 open-grained sandstone — contain, like the mosses of the 
 country, ancient human remains and Avorks of art. There 
 have been detected among the older sand dunes of Moray, 
 broken or partially finished arrow-heads of flint, with splin- 
 tered masses of the material out of Avhich they had been 
 fashioned, — the debris, apparently, of the workshop of 
 some Aveapon-maker of the stone period. Among a tract 
 of sand dunes on the shores of the Cromarty Frith, imme- 
 diately under the Northern Sutor, in a hillock of blown 
 sand, which was laid open about eighty years ago by the 
 winds of a stormy Avinter, there was found a pile of the 
 bones of the A'arious animals of the chase, and the horns 
 of deer, mixed Avith the shells of molluscs of the edible 
 species; and, judging from the remains of an ancient hill- 
 fort in the neighborhood, and from the circumstance that 
 under an adjacent dune rude sepulchx'al urns were dis- 
 interred many years after, I have concluded that the hunt- 
 ers by Avhom they had been accumulated could not ha\'e 
 flourished later than at least the age of bronze. It Avas 
 ascertained in one of the Orkneys, about the year 1819, 
 that a range of similar dunes, partially cleared by a long 
 tract of high winds from the west, had overlain for untold 
 ages what seemed to be the remains of an ancient Scan- 
 dinavian village. In fine, very strange fossils of the human 
 period has this sand deposit of subaerial formation been 
 found to contain. There AA^ere disinterred on the Cornish 
 coast in 1835, out of an immense Avreath of sand, an old 
 British church and oratory, — the church and oratory of 
 Perran-sabulae, — which had been hidden from the eye of
 
 LECTURES ON GEOLOGY. 49 
 
 man for nearly a thousand years. The Tractarian contro- 
 versy had just begun at the time to agitate the Episcopacy 
 of Enghmd ; it had become of importance to ascertain the 
 exact form of building sanctioned by antiquity as most 
 conducive to devotion ; and a fossil church, whicTi had un- 
 dergone no change almost since the times of the ancient 
 Christianity, Avas too interesting a relic to escape the notice 
 of the parties which the controversy divided. But though 
 antagonistic volumes were written regarding it, in a style 
 not quite like that in which Professor Owen and Dr. Man- 
 tell have since discussed the restoration of the Belemnite, 
 it was ultimately found that the little old church of St. 
 Pirran the Culdee — such a building as Robinson Crusoe 
 might have erected for the ecclesiastical uses of himself 
 and his man Friday — threw exceedingly little light on 
 the vexed question of church architecture. The altar is in 
 the east, said the Tractarians. Nay, the building itself does 
 not lie east and west, replied their opponents. We grant 
 you it does not, rejoined the Tractarians ; but its gable 
 fronts the point where the sun rises on the saint's birthday. 
 Who knows that? exclaimed their opponents : besides, the 
 sacred gable was unfurnished with a window. We deny 
 that, said the Tractarians; the laborer who saw it just ere 
 it fell says there was a large hole in it. And thus the con- 
 troversy ran on, undoubtedly amusing, and, I daresay, very 
 instructive. The north of Scotland has its ancient fossil 
 barony underlying a wilderness of sand ; ploughed fields 
 and fences, with the walls of turf-cottages, and the remains 
 of a manor-house, all irrecoverably submerged; — and we 
 find the fact recorded in a Scotch act of the times of Wil- 
 liam III. Curious, as being perhaps the only act of Par- 
 liament in existence to which the geologist could refer for 
 the history of a deposit, I must take the liberty of submit-
 
 50 LECTURES ON GEOLOGY, 
 
 ting to you a small portion of one of its long sentences. 
 " Our Sovereign Lord," says the preamble, " considering 
 that many lands, meadows, and pasturages, lying on the 
 sea-coasts, have been ruined and overspread in many parts 
 of this kingdom by sand driven from sand-hills, the which 
 has been mainly occasioned by the pulling up of the roots 
 of bent, juniper, and broom bushes, which did loose and 
 break the surface and scroof of the sand-hills ; and partic- 
 ularly, considering that the barony of Cawbin, and house 
 and yeards thereof, lying within the sherilFdom of Elgin, is 
 quite ruined and overspread with sand, the which was oc- 
 casioned by the foresaid bad. practice of pulling the bent 
 and juniper, — does hereby strictly prohibit," etc., etc., etc. 
 I have Avandered for hours amid the sand-wastes of this 
 ruined barony, and seen only a few stunted bushes of 
 broom, and a few scattered tufts of withered bent, occupy- 
 ing, amid utter barrenness, the place of what, in the middle 
 of the seventeenth century, had been the richest fields of 
 the rich province of Moray ; and, where the winds had 
 hollowed out the sand, I have detected, uncovered for a 
 few yards'-breadth, portions of the buried furrows, sorely 
 dried into the consistence of sun-burned brick, but largely 
 charged with the seeds of the common corn-field weeds of 
 the country, that, as ascertained by experiment by the late 
 Sir Thomas Dick Lauder, still retain their vitality. It is 
 said that an antique dove-cot in front of the huge sand- 
 wreath which enveloped the manor-house, continued to 
 present the top of its peaked roof over the sand, as a foun- 
 dered vessel sometimes exhibits its vane over the waves, 
 until the year 1760. The traditions of the district testify 
 that, for many years after the orchard had been euA'eloped, 
 the topmost branches of the fruit-tre^s, barely seen over 
 the surface, continued each spring languidly to throAv out
 
 LECTURES ON GEOLOGY. 51 
 
 burl and blossom ; and it is a curious circumstance, that in 
 the neighboring churchyard of Dike there is a sepulchral 
 monument of the Culbin family, which, though it does not 
 date beyond the reign of James VI., was erected by a 
 lord and lady of the last barony, at a time when they 
 seem to have had no suspicion of the utter ruin which was 
 coming on their house. The quaint inscription runs as 
 follows : 
 
 VALER : KIJTNAIRD : ELIZABETH : IXXIS : 1613 : 
 
 THE : BTILDAKS : OP : THIS : BED : OF : STANE : 
 
 AK : LAIRD : ASD : LADIE : OF : COVBINE : 
 
 QVHILK : TVA : AND : THARS : QVHAXE : BRAITHE IS : GANE : 
 
 PLEIS : GOD : VIL : 8LEIP : THIS : BED : VITHIJJ : 
 
 I refer to these facts, though they belong certainly to no 
 very remote age in the past history of our country, chiefly 
 to show that in what may be termed the geological forma- 
 tions of the human period very curious fossils may be 
 already deposited, awaiting the researches of the future. 
 As we now find, in raising blocks of stone from the quarry, 
 water-rippled surfaces lying beneath, fretted by the tracks 
 of ancient birds and reptiles, there is a time coming when, 
 under thick beds of stone, there may be detected fields and 
 orchards, cottages, manor-houses, and churches, — the me- 
 morials of nations that have perished, and of a condition 
 of things and a stage of society that have forever i>assed 
 away. 
 
 Sand dunes and morasses are phenomena of a strictly local 
 character. The last great geological change, general in its 
 extent and efifects, of which Scotland was the subject, was 
 a change in its level, in relation to that of the ocean, of 
 from fifteen to thirty feet. At some unascertained period, 
 regarded as recent by the geologist, — for man seems to 
 have been an actor on the scene at the time, — but remote
 
 52 LECTURES ON GEOLOGY. 
 
 by the historian, — for its date is anterior to that of his 
 oldest authorities in this country, — the land rose, appar- 
 ently during several interrupted paroxysms of upheaval, so 
 that there was a fringe of comparatively level sea-bottom 
 laid dry, and added to the country's area, considerably 
 broader than that which we now see exposed by the ebb of 
 every stream tide. And what I must deem indubitable 
 marks of this change of level can be traced all around Scot- 
 land and its islands. The country, sa^e in a few interrupted 
 tracts of precipitous coast, where the depth of the water, 
 like that beside a steep mole whose base never dries at ebb, 
 precluded any accession to the land, presents around its 
 margin a double coast line, — the line at present washed 
 by the waves, and a line now covered with grass, or waving 
 with shrubs, or skirted by walls of precipice perforated Avith 
 caves, against which the surf broke for the last time more 
 than two thousand years ago. These raised beaches form 
 a peculiar feature in our Scottish scenery, which you must 
 have often remarked. In passing along the public road be- 
 tween Portobello and Leith, the traveller sees upon the 
 left hand a continuous grassy bank, with a line of willows 
 atop, which he may mark in some places advancing in low 
 promontories, in others receding into shallow bays, and 
 which is separated from the present coast line, which in 
 general flatness it greatly resembles, by a strip of rich 
 meadow land, varying from one to three hundred yards in 
 breadth. The continuous grassy bank is the old coast line ; 
 and the gently sloping margin of green meadow is the strip 
 of flat sea-beach along which the tides used to rise and fall 
 twice every twenty-four liours, ere the retreat of the sea 
 within its present bounds. Should it be low ebb at the 
 time, one may pass from the ancient to the recent sea- 
 beach ; the one waving with grass, the other brown with
 
 LECTURES ON GEOLOGY. 53 
 
 algae ; the one consisting, under its covering of vegetable 
 mould, of stratified gravels and sand, blent with the de- 
 cayed shells of mollusca that died more than twenty cen- 
 turies since ; the other formed of exactly the same sort of 
 lines of stratified sand and gravel, and strewed over by 
 shells that were thrown ashore by the last tide, and that 
 lived only a few weeks ago. And, rising over the lower, 
 as over the upper flat, Ave see a continuous escarpment, 
 which marks where, in the present age, during the height 
 of stream tides, the sea and the land meet ; just as the up- 
 per willow-crested escarpment indicates where they met of 
 old. The two escarpments and tlie two gently sloping 
 planes at their base are repetitions of the same phenomena, 
 save that the upper escarpment and upper plane are some- 
 what softer in their outline than the lower, — an effect of 
 the wear of the elements, and of the accumulation of the 
 vegetable mould. There is as thorough an identity between 
 them as between two contiguous steps of a stair, covered, 
 the one by a patch of brown, and the other by a patch of 
 green, in the pattern of the stair-carjiet. There are other 
 parts of our Scottish shores in which the old coast line is 
 of a much bolder character than anywhei'e in this neigh- 
 borhood, and the plane at its base of greater breadth. On 
 the Forfarshire coast, the Dimdee and Arbroath Railway 
 runs along the level margin, once a sea-bottom, which at 
 one point, opposite the parish church of Barrie, is at length 
 two miles in breadth, and the old coast line rises from thirty 
 to fifty feet over it. It is strongly marked on the southern 
 side of the Dornoch Frith, immediately below and for sev- 
 eral miles to the east of the town of Tain, where it attains 
 a breadth of from one to two miles, and where the old sea- 
 margm, rising over the cottage-mottled plain below in a 
 series of jutting headlands, with green bosky bays between, 
 
 5*
 
 54 LECTURES ON GEOLOGY. 
 
 strikes even the least practised eye as joossessed of all tlie 
 characteristic peculiarities of a true coast line. It is scarce 
 less marked in the neighborhood of Cromarty, and on the 
 opposite shore of the Cromarty Frith, in the parish of Nigg. 
 It runs along by much the greater portion of the eastern 
 coast of Sutherland ; and forms at the head of Loch Fleet, 
 in the neighborhood of Dornoch, a long withdrawing frith, 
 bounded by picturesque shores, and covered by a short, 
 green sward, level as the sea in a calm, on which groups 
 of willow and alder trees take the place of busy fleets, and 
 the hare and the partridge that of the coot and the por- 
 poise. Along the upper recesses of almost all our flatter 
 friths, such as the friths of Beauly, of Dingwall, and of the 
 Tay, and of the Clyde, it exists as fertile tracts of carse- 
 land ; the rich links of the Forth, rendered classical by the 
 muse of Macneil, belong to it ; it furnishes, in various other 
 localities more exposed to the open sea, ranges of sandy 
 links of a less valuable character, such as the range in our 
 own neighborhood occupied by the race-course of Inveresk; 
 and not a few of the seapo-rts and watering places of the 
 country, such as the greater part of Leith, Portobello, 
 Musselburgh, Kirkaldy, Dundee, Dingwall, Invergordon, 
 Cromarty, Wick, Thurso, Kirkwall, Oban, and Greenock, 
 have been built ii))on it. 
 
 The old coast line, with the flat marginal selvage at its 
 base, form, as I have said, well-marked features in the 
 scenery of the island. Geology may be properly regarded 
 as the science of landscape : it is to the landscape painte" 
 what anatomy is to the historic one or to the sculptor. "^ 
 the singularly rich and variously compounded prospects 
 of our country there is scarce a single trait that cannot 
 be resolved into some geological peculiarity in the coun- 
 try's framework, or Avhich does not bear witness otherwise
 
 LECTURES OX GEOLOGY. 65 
 
 and more directly than from an}^ mere sugge"stion of the 
 associative faculty, to some striking event in its physical 
 history. Its landscapes are tablets roughened, like the 
 tablets of Nineveh, with the records of the past ; and their 
 various features, whether of hill or valley, terrace or escarp- 
 ment, form the bold and graceful characters in which the 
 narrative is inscribed. As our Scottish geologists have 
 given less attention to this special dejDartment of their 
 science than to perhaps any other, — less, I am disposed to 
 think, than, from its intrinsic interest and its bearing on 
 art, is fairly owing to it, — I shall take the liberty — cast- 
 ing myself on the forbearance of such of my audience as 
 are least artistic in their tastes — of occasionally touching 
 upon it in my course. 
 
 I need scarce refer to the scenery of our mosses, — these 
 sombre, lake-like tracts, divested, however, of the cheerful 
 gleam of the water, — that so often fatigue the eye of the 
 traveller among our mountains, but which at that season 
 when the white cottony carnach mottles their dark sur- 
 faces, reminding one of tears on a hatchment, — when the 
 hills around, purple with the richly-blossoming heath, are 
 chequei-ed with the light and shade of a cloud-dappled 
 sky, — and when, in the rough foreground, the gray upright 
 stone of other days waves its beard of long gray lichen to 
 the breeze, — are not unworthy, in their impressive loneli- 
 ness, of employing, as they have oftener than once done, 
 the magic pencil of a Macculloch. I need as little refer to 
 the scenery of those sand dunes which gleam so brightly 
 amid some of our northern landscapes, and which, not 
 only in color, but also in form, contrast so strongly with 
 our morasses. The dark flat morass is suggestive always 
 of sluggish and stagnant repose ; whereas, among our sand 
 dunes, from the minuter ripple-markings of the general
 
 56 LECTURES ON GEOLOGY. 
 
 surface to the wave-like form of the hills sloped in the 
 direction of the prevailing winds, and curved, like snow- 
 wreaths, to the o2:)posite point of the compass, almost every 
 outline is equally suggestive of motion. I could, however, 
 fain borrow the pencil of our countryman Hill, as he em- 
 ploys it in his exquisite cabinet-pictures, to portray the 
 story of the last Barony: rolling hills of sand all around, 
 the red light of a stonny summer evening deepening into 
 dun and lurid brown, through an eddying column of suf- 
 focating dust snatched up by a whirlwind ; the antique 
 garden-dial dimly shadowing forth the hour of sunset for 
 the last time, amid half-submerged shrubs and trees ; and, 
 full in the centre of the picture, a forlorn fortalice of the 
 olden time, with the encroaching wreath rising to its lower 
 battlements, like some wrecked vessel on a wild lee-shore, 
 with the angry surf raging high over her deck, and kissing 
 with its flame-like tips the distant yards. 
 
 The scenery of the old coast line possesses well-nigh all 
 the variety of that of the existing coast ; but it substitutes 
 field and meadow for the blue sea, and woods and human 
 dwellings for busy mast-crowded harbors, and fleets riding 
 at anchor. It is pleasing, however, to see headland jutting 
 out beyond headland into some rich plain, traversed by 
 trim hedge-rows and green lanes ; or some picturesque 
 cottage, overshadowed by its gnarled elm, rising in some 
 bosky hollow at the foot of the swelling bank or weather- 
 stained precipice, beneath which the restless surf once 
 broke against the beach. There are well-marked si)eci- 
 mens of this scenery of the ancient coast line in our imme- 
 diate neighborhood. Musselburgh, with its homely Saxon 
 name, lies in the middle of what was once a flat sandy bay, 
 now laid out into fields, gardens, and a race-course; and 
 the old coast escarpment, luxuriant with hanging woods,
 
 LECTURES ON GEOLOGY. 57 
 
 and gay with villas, and which may possibly have been its 
 first Celtic designation, Inveresk^ ere the last upheaval of 
 the land, half closes around it. The church and burying- 
 ground occupy the toj3 of a long ridge, that had once been 
 a river-bar, heajied up apparently by the action of the 
 waves on the one side, and by that of the stream on the 
 other. But, as shown by the remains of Roman baths and 
 a Roman rampart, which once occupied its summit, it must 
 have borne its present character from at least the times of 
 Lollius Urbicus, — perhaps for several centuries earlier. 
 The neighboring port of Portobello, as seen from the east, 
 just as it comes full in sight on the Musselburgh road, 
 seems set so completely in a framework of the ancient 
 escarpment, that it derives from it its natural features. 
 But it is where, along our boulder shores, lines of steep 
 precipices have been elevated over the sea, so that the 
 waves no longer reach their bases, that the old coast sce- 
 nery is at once most striking and peculiar. Tall picturesque 
 stacks, which had once stood up amid the surf, brown and 
 shaggy with the serrated fucus and the broad-fronded lara- 
 inara, now rise out of thickets of fern or sloethorn, ,and 
 wave green with glassy ivy and the pendant honeysuckle. 
 Deep caverns, too, in which the billows had toiled for ages, 
 but now silent, save when the drop tinkles from above into 
 some cool cistern half hidden in the gloom of the interior, 
 open along the wall of cliffs ; and over projecting buttresses 
 of rock, perforated often at their bases as if by Gothic 
 archways, and thickly mantled over by liverworts, green 
 and gray, the birch hangs tremulous from above, or the 
 hazel shoots out its boughs of brighter green, or the raoun- 
 tain-ash hangs its scarlet berries. One of the most pleasing 
 landscapes of one of the most accomplished of female 
 artists — Miss Stoddart — has as its subject an ancient
 
 58 LECTURES ON GEOLOGY. 
 
 escarpment of this bold character, which occurs in Arran. 
 A mossy, fern-tufted meadow, skirted by the sea, roughened 
 by what had once been half-tide skerries, and enlivened 
 by a Highland cottage, stretches out into the foreground 
 from an irregular Avail of rock, overhung by graceful foli- 
 age, hollowed into deep recesses, adown which the waters 
 tinkle, and with some of its bolder projections perforated 
 at the base like flying buttresses of the decorated Gothic ; 
 and such is the truth of the re2:)resentation, that we at 
 once determine that the artist had chosen as her subject 
 one of the more precipitous reaches of the old coast line, 
 and that its wall of rock must have derived much of the 
 peculiarity of trait so happily caught, from the action of 
 the waves. Again, in direct contrast with this striking 
 type of old coast escarpment, though in its own way 
 not less striking, Mr. Hill's fine picture, " The Sands at 
 Sunrise," lately engraved by the Art Union, exhibits as its 
 background one of those long, flat, sandy spits, products 
 of the last upheaval, which, stretching far into the sea, 
 bear amid the light of day an air of even deeper loneliness 
 than our woods and fields when embrowned by the gather- 
 ing night. When the insulated stacks of an old coast line 
 are at once tall and attenuated, and of a white or jDale- 
 colored rock, the effect, especially when viewed by moon- 
 light, is singularly striking. The valley of the Seine, as 
 described by Sir Charles Lyell, — now a valley, but once 
 a broad frith, — is flanked on each side, in its lower reaches, 
 by tall stacks of white chalk, of apparently the same age 
 as those of the ancient coast line of our own country; 
 and, seen ranged along their green hill-sides, in the imper- 
 fect light of evening, or by the rising moon, they seem the 
 sheeted spectres of some extinct tribe of giants. 
 
 The date of that change of level which gave to Scot'
 
 LECTURES ON GEOLOGY. 59 
 
 land this flat fringe of margin-land, with its picturesque es- 
 carpment of ancient coast, we cannot positively fix. We 
 find reason to conclude that it took place previous to the age 
 of the Roman invasion. It has been shown, from evidence 
 of a semi-geologic, semi-archaeologic character, by one of 
 our highest authorities on the subject, Mr. Smith of Jor- 
 danhill, that the land must have stood at a not lower level 
 than now, when the Roman wall which connects the friths 
 of Forth and Clyde was completed. For, had it been 
 otherwise, some of the terminal works which remain would 
 have been, what they obviously were not, under the sea 
 line at the time. In the sister kingdom, too, which has 
 also its old coast line, St. Michael's Mount in Cornwall, 
 which was connected with the mainland at low water by 
 a strij^ of beach in the times of Julius Cnesar, — a fact 
 recorded by Diodorus Siculus, — is similarly connected 
 with the mainland at low water still. But though the 
 upheaval of the old coast line is removed thus beyond the 
 historic period, it seems to have fallen, as I have said, 
 within the human one: man seems to have been an inhab- 
 itant of the island when its general level was from twenty 
 to forty feet lower than now, and the waves broke at full 
 tide against tlie old coast line. " The skeleton of a Balae- 
 noptera," says Professor Owen, "seventy-two feet in length, 
 was found," about thirty years ago, " imbedded in the clay 
 on the banks of the Forth, more than twenty feet above 
 the reach of the highest tide." And again, " Several bones 
 of a whale," ^ he continues, " were also discovered at Dun- 
 more rock, Stirlingshire, in brick-earth, nearly forty feet 
 above the present sea-level." These whales must have 
 been stranded when the old coast line was washed by the 
 
 1 Bones of the whale have been found in the clay of the Avon and 
 Severn drifts, in a similar position. ~ W. S. S.
 
 60 LECTURES ON GEOLOGY. 
 
 waves, and the marginal strip existed as an oozy sea-bot. 
 torn ; and yet in both cases there were found, among the 
 bones, primitive weajjons made of the pointed branches 
 of deer's horns, hollowed at their broad ends by artificial 
 perforations ; and in one of these perforations the decayed 
 fragments of a wooden shaft still remained. The pointed 
 and perforated pieces of horn were evidently rude lance- 
 heads, that in all probability had been employed against 
 the stranded cetacea by the savage natives. Further, where 
 the city of Glasgow now stands, three ancient boats — 
 one of which may be seen in the Museum of our Scottish 
 Antiquaries in Edinburgh, and another in the Andersonian 
 Museum — have been dug up since the year 1781 ; the last 
 only four years ago. One of the number was found a full 
 quarter of a mile from the Clyde, and about twenty-six 
 feet above its level at high water. It reposed, too, not on 
 a laminated silt, such as the river now deposits, but on a 
 pure sea sand. "It therefore appears," says Mr. Robert 
 Chambers, in his singularly ingenious work on " Raised 
 Beaches," "that we have scarcely an alternative to the 
 supposition that when these vessels foundered, and were 
 deposited where in modern times they have been found, the 
 Frith of Clyde was a sea several miles wide at Glasgow, 
 covering the site of the lower districts of the city, and 
 receiving the waters of the river not lower than Bothwell 
 Bridge." I may add, that the Glasgow boat in the Anti- 
 quarian Museum is such a rude canoe, hollowed out of a 
 single trunk, as may be seen in use among such of the 
 Polynesian islands as lie most out of the reach of civiliza- 
 tion, or in the Indian Archipelago, among the rude Alforian 
 races; and that in another of these boats — the first dis- 
 covered — there was found a beautifully polished hatchet 
 of dark greenstone, — an unequivocal indication that they
 
 LECTUKES ON GEOLOGY. 61 
 
 belonged to the "stone period," There are curious ety- 
 ftiologies traceable among the older Celtic names of places 
 in the country, which I have sometimes heard adduced in 
 evidence that it was inhabited, ere the last upheaval of the 
 land, by the ancient Gaelic-speaking race. Eminences that 
 rise in the flat marginal strip, and which, though islands 
 once, could not have been such since the final recession of 
 the sea, continue to bear, as in the neighborhood of Stir- 
 ling, the Gaelic prefix for an island. But as the old Celts 
 seem to have been remarkable as a people for their nice 
 perception of resemblances, the insular form of these emi- 
 nences may be perhaps regarded as suggestive enough to 
 account for their names. One of these etymologies, how- 
 ever, which could scarce have been founded on any mere 
 resemblance, seems worthy of special notice. Loch Ewe, 
 in Ross-shire, one of our salt sea lochs,.receives the waters 
 of Loch Maree, — a noble fresh-water lake, about eighteen 
 miles in length, so little raised above the sea-level, that 
 ere the last upheaval of the land it must have formed 
 merely the upper reaches of Loch Ewe. The name Loch 
 Maree — Mary's Loch — is evidently mediaeval. And, curi- 
 ously enough, about a mile beyond its upper end, just 
 where Loch Ewe would have terminated ere the land 
 last arose, an ancient farm has borne from time immemo- 
 rial the name of Kinlochewe, — the head of Loch Ewe. 
 Dispose, however, of the etymologies as we may, there are 
 facts enough on record which render it more than probable 
 that, though the general change of level to which we owe 
 the old coast line in Scotland does not lie within the his- 
 toric ages, it is comprised within the human period. But 
 we cannot, as has been shown, fix upon a date for the 
 event. 
 
 Were the case otherwise, — could we fix with any cer- 
 
 6
 
 62 LECTURES OX GEOLOGY. 
 
 tainty tlie time when this change of level took place, and 
 the platform of the lower coast line was gained from the 
 sea, — there might be an approximation made to the ante- 
 rior space of time during which the line of high water had 
 been the willow-crowned escarpment beyond Portobello 
 and the green bank near Rutherglen, and the sea rose far 
 beyond its present limits in our friths and bays. There 
 are portions of the coast that at this early period presented 
 to the waves lines of jirecipices that are now fringed at 
 their bases by strips of verdure, and removed far beyond 
 their reach. There are other portions of coast in the 
 immediate neighborhood of these, where similar lines of 
 precipices, identical in their powers of resistance, were 
 brought by the same movement within that very influence 
 of the waves beyond which the others had been raised. 
 And each line bears, in the caves with which it is fretted, 
 — caves hollowed by the attrition of the surf in the direc- 
 tion of faults, or where masses of yielding texture had 
 been included in the solid rock, — indices to mark, propor- 
 tionally at least, the respective periods during which they 
 were exposed to the excavating agent. Thus, the aver- 
 age depth of the ancient caves in an exposed line of coast, 
 as ascertained by dividing the aggregate sum of their 
 depths by their number, and the average depth, ascertained 
 by the same process, of the recent caves, equally exposed 
 on the same coast, and hollowed in the s.ime variety of 
 rock, could scarce fail to represent their respective periods 
 of exposure, had we but a given number of years, histor- 
 ically determined, to set off against the average measure- 
 ment of the recent excavations. Even wanting that, how- 
 ever, it is something to know, that though the sea has 
 stood at the existing sea-margin since the days of Agric- 
 ola, and at least a few centuries more, it stood for a con-
 
 LECTURES ON GEOLOGY. 63 
 
 siderably longer period at tlie old coast line. The rock 
 of which thosG remarkable promontories, the Sutors of 
 Cromarty, are composed, is a granite gneiss, much trav- 
 ersed by foults, and inclosing occasional masses of a soft 
 chloritic schist, that yields to the waves, while the sur- 
 romiding gneiss — hard enough to strike fire with steel — 
 remains little afiected by the attrition of centuries. These 
 pi'omontories have, in consequence, their numerous caves 
 ranged in a double row, — the lower row that of the exist- 
 ing coast, the upper that of the old one ; and I have 
 examined both rows with some little degree of care. The 
 deepest of the recent caves measures, from the opening to 
 its inner extremity, where the rock closes, exactly a hun- 
 dred feet ; the deepest of the ancient ones, now so com- 
 pletely raised above the surf, that in the highest tides, and 
 urged upwards by the severest storms, the waves never 
 reach its mouth, measures exactly a hundred and fifty feet. 
 And these depths, though much beyond the respective 
 average depths of their several roAvs, bear, so far as I could 
 ascertain the point, the proportions to each other that 
 these averages bear. The caves of the existing coast line 
 are as two in depth, and those of the old coast line as three. 
 If the excavation of the recent caves be the work of tico 
 thousand years, the excavation of the ancient caves must 
 have been the work of three thousand ; or, as two thou- 
 sand does not bring us much beyond the Roman period, 
 let us assume as the period of the existing coast line and 
 its caves, two thousand two hundred years, and as the 
 proportional period of the old coast line, three thousand 
 three hundred more. Both sums i;nited bring us back 
 five thousand five hundred years. How much more an- 
 cient either coast line may be, we of course cannot deter- 
 mine : we only know that, on the lowest possible assump-
 
 64 LECTURES ON GEOLOGY. 
 
 tion, we reach a period represented by their united ages 
 only less extended by six years than that which the Sa- 
 maritan chronology assumes as the period during which 
 man has existed upon earth, and only three hundred and 
 fifty-five years less than that assumed by the Masoretic 
 chronology. The 'chronology of the Septuagint, which 
 many have begun to deem the most adequate of the three, 
 adds about five hundi-ed and eighty-six years to the sum 
 of the latter. 
 
 Permit me, in closing this part of my subject, to show 
 you that changes of level such as that to which we oAve 
 our old coast line in Scotland, and the marginal strip of 
 dry land which we have laid out into so many pleasant 
 gardens and fields, and on which we have built so many 
 of our seaport towns, are by no means very rare events 
 to the geologist. He enumerates at least five localities in 
 the Old World, — Scandinavia, part of the west coast of 
 Italy, the coasts of Cutch and of Arracan, and part of the 
 kingdom of Luzan, in which the level is slowly changing 
 at the i^resent time ; and in the New World there are vast 
 districts in which the land suddenly changed its level for 
 a higher one during the present century, "On the 19th 
 of November 1822," says Sir Charles Lyell, "the coast of 
 Chili was visited by a most disastrous earthquake. When 
 the district around Valparaiso was examined on the morn- 
 ing after the shock, it was found that the whole line of 
 coast for the distance of above one hundred miles was 
 raised above its former level. At Valparaiso the elevation 
 was three feet, and at Quinteno about four feet. Part of 
 the bed of the sea remained bare and dry at high water, 
 with beds of oyster, mussel, and other shells, adhering to 
 the rocks on which they grew, — the fish being all dead, 
 and exhaling offensive effluvia." Again, on the east side
 
 LECTURES ON GEOLOGY. 65 
 
 of the Bay of Bengal, upon the coast of Arracan, which is 
 at present in the course of rising, there are ishands which 
 present on their shores exactly such an appearance as our 
 own country would have presented some sixty or a hun- 
 dred years after the elevation of the old coast line. The 
 island of Reguain, one of these, was carefully surveyed in 
 the year 1841 by the officers of her Majesty's brig Chil- 
 ders : and it has been carefully mapped in the admirable 
 Physical Atlas of the Messrs. Johnston of Edinburgh. 
 We find it, as shown in the map, resembling three islands ; 
 the one jjlaced within the other, as, to employ a homely 
 illustration, the druggist, to save room, places his empty 
 pill-boxes the one within the other. Fii-st, in the centre, 
 there is the ancient island, with a well-defined coast line, 
 some six or eight feet high, running all around it. At the 
 base of this line there is a level sea of rich paddy fields, — 
 for what may be termed the second island has been all 
 brought into cultivation; and it has also its coast line, 
 which descends some six or eight feet more, to the level 
 of a third island, which was elevated over the sea not 
 more than eighty years ago, and which is still unculti- 
 vated ; and the third inland is surrounded by the existing 
 coast line. Thus the centre island of Reguain consists of 
 three great steps or platforms, each of which marks a par- 
 oxysm of elevation ; and, with the upheaval of the coast 
 of Chili, and a numerous class of events of a similar chai*- 
 acter, it enables us to conceive of the last great geological 
 change of which our country was the subject. We imag- 
 ine a forest-covered land, marked by the bold, command- 
 ing features by which we recognize our country, but in- 
 habited by barbarous, half-naked tribes, that dwell in rude 
 circular wigwams, formed of the branches of trees, — that 
 employ in war or the chase weapons of flint or jasper, 
 
 6*
 
 66 LECTURES ON GEOLOGY. 
 
 — and that navigate their rivers or estuaries in canoes 
 hollowed by fire out of single logs of wood. There has 
 been an earthquake during the night ; and when morning 
 rises, the beach shows its broad, darkened strip of apparent 
 ebb, though the tide is at full at the time ; and when 
 the waters retire, they leave vast uncovered tracts never 
 seen before, comparatively barren in sea-weed, but rich in 
 stony nulliparite encrustations, minute coralii-es, and fleshy 
 sponges. Ages elapse, and civilization grows. The added 
 belt of level land is occupied to its utmost extent by man : 
 he lays it out into gardens and fields, and builds himself a 
 dwelling upon it : but no sooner has he rendered it of 
 some value, than the sea commences with him a course 
 of tedious litigation for the recovery of its property ; and 
 bit by bit has it been Avresting it out of his hands. Almost 
 all those tracts on our coasts which have been suffering 
 during the last few centuries from the encroachment of 
 the waves, and which have to be protected against their 
 fury wherever land is valuable, as in this neighborhood, by 
 lines of bulwarks, belong to the flat marginal strip won 
 from them by the last change of level. 
 
 Our next great incident in the ^ologic history of Scot- 
 land dates, it would seem, beyond the human period. In 
 passing along the beach between Musselburgh and Porto- 
 bello, or again between Portobello and Leith, or yet again 
 between Leith and Newhaven, one sees an exceedingly 
 stiff, dark-colored clay, charged with rounded pebbles and 
 boulders, and which, where washed by the waves, presents 
 a frontage nearly as steep as that of the rock itself The 
 deposit by which it is represented is known technically to 
 the agriculturist as Till, and to the geologist as the Boul- 
 der-Clay. Though not continuous, it is of very general 
 occurrence, in the Lowlands of Scotland, and presents,
 
 LECTURES ON GEOLOGY. (57 
 
 though it varies in color and composition, according to the 
 nature of the rocks which it overlies, certain unique ap- 
 peai'ances, which seem to connect its oi'igin in the several 
 localities with one set of causes, and which no other 
 deposit presents. Like the raised beaches, it has contrib- 
 uted its distinctive quota to the variously featured scenery 
 of our country. The Scottish word scaur., in the restricted 
 significancy attached to it in many parts of the kingdom, 
 means simply a precipice of clay; and it is almost invari- 
 ably the boulder-clay that forms scaurs in Scotland ; for 
 it is one of the peculiarities of the deposit, that it stands 
 up well-nigh as steeply over the sides of rivers, or on 
 encroaching sea-beaches, or on abrupt hill-sides, as rock 
 itself; and these clay precipices bear almost invariably a 
 peculiar set of characters of their own. In some cases 
 they spring up as square and mural, seen in front, as cliffs 
 of the chalk, but seen in profile, Ave find their outlines 
 described by parabolic curves. In other cases Ave see the 
 vegetable mould rendered coherent by the roots of shrubs 
 and grasses projecting over them atop, like the cornice of 
 some edifice oA^er its frieze. In yet other cases, though 
 abrupt as precipices of solid rock, we find them seamed by 
 the Aveather into numerous divergent channels, with py- 
 ramidal peaks between ; and, thus combining the perpen- 
 dicularity of true clifis Avith the rain-scooped fun-ows of a 
 yielding soil, they present eccentricities of aspect Avhich 
 strike, by their grotesqueness, eyes little accustomed to 
 detect the picturesque in landscape. Such are some of 
 the features of the scaurs of our country, — a well-marked 
 class of precipices for which the English language has no 
 name. It is, hoAve\'er, in continuous grass-covered escarp- 
 ments, which in some parts form the old coast line, and 
 rise in others along the sides of i-ivers, that we detect at
 
 68 LECTURES ON GEOLOGY. 
 
 once the most marked and most graceful scenic peculiarity 
 of the boulder-clay. The steep slopes, furrowed by enor- 
 mous flutings, like those of the antique Doric, appear as 
 if laid out into such burial-mounds as those with which a 
 sexton frets the sm^face of a country churchyard, but with 
 this difference, that they seem the burial-mounds of giants 
 tall and bulky as those that of old warred against the 
 gods. On a grass-covered escarpment of the boulder-clay 
 in the neighborhood of Cromarty these mounds are strik- 
 ing enough to have caught the eye of the children of the 
 place, and are known among them as the giants' graves. 
 They lie against the green bank, each from forty to sixty 
 yards in length, and from six to ten yards in height, with 
 their feet to the shore, and their heads on the top of the 
 escarpment ; and when the evening sun falls low, and the 
 shadows lengthen, they form, from their alternate bars of 
 light and shade, that remind one of the ebon and ivory 
 buttress of the poet, a singularly pleasing feature in the 
 landscape. I have sometimes wished I could fix their fea- 
 tures in a calotype, for the benefit of my friends the land- 
 scape painters. This vignette, I would fain say, represents 
 the boulder-clay after its precipitous banks — worn down, 
 by the frosts and rains of centuries, into parallel runnels, 
 that gradually widened into these hollow grooves — had 
 sunk into the angle of inclination at which the disintegrat- 
 ing agents ceased to opex'ate, and the green sward covered 
 all up. You must be studying these peculiarities of aspect 
 more than ever you studied them before. There is a time 
 coming when the connoisseur will as rigidly demand the 
 specific character of the various geologic deposits in your 
 rocks and scaurs, as he now demands specific character iu 
 your shrubs and trees. 
 
 I have said that the boulder-clay exhibits certain unique
 
 LECTURES ON GEOLOGY. 69 
 
 appearances, which connect its origin in the several locali- 
 ties with one set of causes, and which no other deposit 
 presents. On examining the boulders which it encloses, 
 we find them strongly scarred and scratched. In most 
 instances, too, the rock on whicli the clay rests, — if it be 
 a trap, or a limestone, or a finely-grained sandstone, or, in 
 short, any rock on which a tool could act, and of a texture 
 fitted to retain the mark of the tool, — we find similarly 
 scarred, grooved, and scratched. In this part of the 
 country, the boulder-clay contains scarce any fossils, save 
 fragments of the older organisms derived from the rocks 
 beneath ; but in both the north and south of Scotland — 
 in Caithness, for instance, and in Wigtonshire — it con- 
 tains numerous shells, which, both in their species and 
 their state of keeping, throw light on the origin of the 
 formation. But of that more anon. Let me first remark, 
 that the materials of the level marginal strip of ancient 
 sea-beach beneath the old coast line seem, like the mate- 
 rials of the existing sea-beach, to have been arranged 
 wholly by the agency of water. But in the boulder-clay 
 we find a class of appearances which mere water could 
 not have produced. Not only are the larger pebbles and 
 boulders of the deposit scratched and grooved, but also its 
 smaller stones, of from a few pounds to but a few ounces, 
 or even less than an ounce, in weight ; and this, too, in a 
 peculiar style and direction. When the stones are de- 
 cidedly of an oblong or spindle shape, the scratchings 
 occur, in at least four cases out of every five, in the line 
 of their longer axis. Now, the agent which produced such 
 effects could not have been simply water, whether im- 
 pelled by currents or in waves. The blacksmith, let him 
 use what strength of arm he may, cannot bring his file to 
 bear upon a minute pin until he has first locked it fast in
 
 70 LECTURES ON GEOLOGY. 
 
 his vice ; and then, though not before, his tool bears upon 
 it, and scratches it as deeply as if it were a beam of iron 
 of a ton weight. Tlie smaller stones must have been 
 fastened before they could have been scratched. Even, 
 however, if the force of water could have scratched and 
 furrowed them, it would not have scratched and furrowed 
 them longitudinally, but across. Stones, when carried 
 adown a stream by the torrent, or propelled upwards along 
 a« beach by the waves, present always their broader and 
 longer surfaces ; and the broader and longer these surfaces 
 are, the further are the stones propelled. They are not 
 launched forwards, as a sailor would say, end on, but tum- 
 bled forwards broadside. They come rolling down a river 
 in flood, or uj^wards on the shore in a time of tempest, as 
 a hogshead rolls down a declivity. In the boulder-clay, 
 on the contrary, most of the pebbles that bear the mark 
 of their transport at all Avere not rolled, but slidden for- 
 ward in the line of their longer axis. They were launched, 
 as ships are launched, in the line of least resistance, or as 
 an arrow or javelin is sent on its course through the air. 
 Water could not have been the agent here, nor yet an 
 eruption of mud, propelled along tlie surface by some 
 wave of translation, produced by the sudden upheaval of 
 the bottom of the sea, or by some great wave raised by an 
 earthquake. 
 
 But if water or an eruption of mud could not have pro- 
 duced such effects as the longitudinal scratching, let us ask 
 what could have produced them? There are various pro- 
 cesses going on around us, by which the scratchings on the 
 solid rocks beneath are occasionally simulated with a less 
 or greater degree of exactness. In some of our shallow 
 Highland fields, for instance, I have seen the rock beneath, 
 or the stones buried at the depth of but a few inches from
 
 LECTURES ON GEOLOGY. t 1 
 
 the surface, scarred by the j^lough with ruts not very 
 unlike the larger ones on the stones and rocks of the 
 boulder-clay; but in these plough-scarred surfaces the 
 polish is wanting. Again, in some of our steeper lanes, if 
 a fine-grained trap has been used in the pavement, we find 
 that it soon polishes and wears down under the iron-armed 
 feet of the passengers, and becomes scratched in the line 
 of their tread, in a style not very distinguishable, save 
 for the absence of the deeper fui-rows, from that of the 
 scratched and polished rock-pavements of the boulder, 
 clay. But I know of only one process by which, on a 
 small scale, all the phenomena of the boulder-clay could 
 be produced, more especially, however, the phenomena of 
 its oblong pebbles scratched in the lines of their longer 
 axis ; and my recollection of that one dates a good many 
 years back. When, more than a quarter of a century ago, 
 the herring fishery began to be prosecuted with vigor in 
 the north of Scotland, many of the Highland woods of 
 natural birch and alder were cut down for the manufacture 
 of barrels, and floated in rafts along the rivers to the sea. 
 And my opportunities of observing these rafts, as they 
 shot along the more rapid reaches of our mountain streams, 
 or swept over their shallower ledges, grazing the bottom 
 as they passed, naturally led me to inquire into their opei*- 
 ations upon the beds of the streams adown which they 
 were floated. Let us advert to some of these. When a 
 large raft of wood, floated down a rapid river, grates 
 heavily over some shallow bank of gravel and j^ebbles 
 resting on the rock beneath, it communicates motion, not 
 of the rolling, but of the lurching character, to the flatter 
 stones with which it comes in contact. It slides ponder- 
 ously over them; and they, with a speed diminished in 
 ratio from that of the moving power in proportion to the
 
 72 LECTURES ON GEOLOGY. 
 
 degree of friction beloAV or around, slide over the stones 
 or rock immediately beneath. And thus, to bcvrrow my 
 terminology from our Scotch law courts, they are con. 
 verted at once into scratchers and scratchees. They are 
 scratched by the grating, sand-armed raft, which of course 
 moA-es quicker than they move ; and they scratch, in turn, 
 the solid mass or embedded fragment along which they 
 are launched. Further, if the gravelly shoals of the 
 sti'eam have, as is not uncommon in the shallows of our 
 Highland rivers, their thickly-set patches of pearl mussels, 
 many of these could scarce miss being crushed and broken ; 
 and we would find not a few of their fragments, if much 
 subjected to the friction of the rafting process, rounded at 
 their edges, and mayhap scratched and polished like the 
 stones. Nor is it difficult to conceive of a yet further 
 consequence of the process. A vast number of rafts 
 dropping down some river, from day to day and year 
 to year, and always grating along the same ledges of sand- 
 stone, trap, or shale, would at length very considerably 
 wear them down ; and the materials of the waste, more or 
 less argillaceous, according to the quality of the rock, 
 would be deposited by the current in the pools and gentler 
 reaches of the stream below. Even the continual tread 
 of human feet in a crowded thoroughfare soon wears down 
 the trap or sandstone pavement, and converts the solid 
 stone into impalpable mud. Further, the color of the 
 mud or clay Avould correspond, as in the thoroaghfare or 
 public road, with the color of the rocks or stones which 
 had been grooved down to form it; and there would 
 occasionally mingle in the mass thus originated, rounded 
 fragments of shells and pebbles, scratched in the line of 
 their longer axis. 
 
 Now, in the boulder-clay we find all these peculiarities
 
 LECTUKES ON GEOLOGY. 73 
 
 •/emarkably exemplified. It contains, as has been shown, 
 the oblong stones scratched longitudinally ; Ave find it 
 thickly charged in various parts of Scotland, though not in 
 our own immediate neighborhood, with worn and rounded 
 fragments of broken shells ; and wo see it almost invaria- 
 bly borrowing its color from the rocks on which it rests, — 
 a consequence, apparently, of its being the dressings of 
 these rocks. There is a peculiar kind of clay which forms 
 on the surfiice of a hearthstone or piece of pavement, 
 under the hands of a mason's laborer engaged in rubbing 
 it smooth with water and a polisher of gritty sandstone. 
 This clay varies in quality and color with the character ot 
 the stone operated upon. A flag of Arbi'oath pavement 
 yields a bluish-coloi-ed clay ; a flag of the Old Red of Ross 
 or Forfarshire, a reddish colored clay; a flag of Suther- 
 landshire Oolite, or of the Upper Old Red of Moray or of 
 Fife, a j^ale yellowish clay. Tlie polishing process is a 
 process which produces clay out of stones, as various in 
 tint as the coloring of the various stones which yield it ; 
 and in almost every instance does the clay thus formed 
 resemble some known variety of the boulder-clay. The 
 boulder-clay, in the great majority of cases, is, both in 
 color and quality, just such a clay as might be produced 
 by this recipe of the mason's laborer, from the rocks on 
 which it rests. The red sandstone rocks of Moray, Cro- 
 marty, and Ross, are covered by red boulder-clays; a 
 similar red boulder-clay overlies the red sandstone rocks 
 of Forfarshire ; and I was first apprised, when travelling in 
 Banffshire some years ago, that I had entered on the dis- 
 trict of the Old Red, by finding the boulder-clay assuming 
 the familiar brick-red hue. Over the pale Oolites of Suth- 
 erlandshire, as at Brora and Golspie, it is of a pale yellow- 
 tint, and of a yellowish red over the pale Old Red Sand- 
 
 7
 
 74 LECTURES ON GEOLOGY. 
 
 stones of the long, flat valley known as the Howe of Fife. 
 Again, in the middle and north-western districts of Caith- 
 ness, where the leaving flagstones so well known in com- 
 merce give to the prevailing rocks of tlie district a sombre 
 tint of gray, the boulder-clay assumes, as in the neighbor- 
 hood of Wick and Thurso, the leaden color of the beds 
 which it overlies; while over the Coal Measures of the 
 south of Scotland, as in East and West Lothian, and 
 around Edinburgh, it is of a bluish-black tint, — exactly 
 the color which might be premised, on the polishing the- 
 ory, from the large mixture of shale-beds, coal-seams, and 
 trap-rocks, which occurs amid the prevailing light-hued 
 sandstones of the deposits beneath. Of coui'se, this con- 
 dition of resemblance in average color between the rocks 
 and the boulder-clays of a district is but of general^ not 
 invariable occurrence, — the boulder-clay is not invariably 
 the dressings of the rocks beneath. We moy occasionally 
 find the trail of the rubbings of one tract overlying, in an 
 easterly direction, the deposits of a different one; just as 
 we would find the rubbings of variously-colored pieces of 
 jDavement laid down to form a floor, and then polished, 
 square by square, where they lay, encroaching, the debris 
 of one squai'e on the limits of another, in the direction of 
 the outward stroke of the polisher. 
 
 But while we thus find all the conditions of a raft- 
 ^ formed deposit in or associated toith the boulder-clay, — 
 such as grooved and furrowed rocks beneath, scratched 
 and polished stones lined longitudinally inclosed in it, 
 accompanied, in not a few instances, by rounded frag- 
 ments of shells, and a general conformity in its color to 
 that of the rocks on which it rests, — where in nature 
 shall we find the analogues of the producing rafts them- 
 selvr^s ? A native of Newfoundland, who season after
 
 LECTURES ON GEOLOGY. 76 
 
 season had seen the Arctic icebergs grating heavily along 
 the coasts of the island, would experience little difficulty 
 in solving the riddle. For rafts of wood we have but to 
 substitute rafts of ice, a submerged land covered by many 
 fathoms of water, for the shallows of the river of my illus- 
 tration, and some powerful ocean current, such as the gulf 
 or arctic stream, for the river itself, and we at once arrive 
 at a consistent theory of the boulder-clay and its origin. 
 Nor must we deem it a thing improbable, that a country 
 like Scotland, which lies between the fifty-fifth and the 
 fifty-ninth degree of north latitude, should be visited 
 every year by icebergs. ISTewfoundland lies from five to 
 eight degrees to the south of Scotland, and yet its north- 
 ern shores are included in that vast cake of ice which, 
 when winter sets fairly in, is found to stretch continu- 
 ously, though in a winding line, over the surface of the 
 ocean, from Nova Zembla in the Old World, to Labrador 
 in the New ; and the drift ice-floes in spring, borne south- 
 wards on the Arctic current, brush every season over its 
 southern shores, or ground by hundreds upon its great 
 bank ; nor do they finally disappear until they reach the 
 fortieth, and, in at least one recorded instance, the thirty- 
 sixth, degree of north latitude. I need scarce remind you 
 that the temperature of a country depends on other causes 
 than its distance from the equator or the pole. The iso- 
 thermal line, or line of mean temperature, of the capital 
 of Iceland, Reikiavik^ in latitude 64, is nearly as high as 
 that of St. John's, the capital of Newfoundland, in lati- 
 tude 47 ; and old York, in the fifty-fourth degree of north 
 latitude, enjoys as much average warmth throughout the 
 year as New York, in the forty-first degree. Now, the 
 causes which give to countries in the same latitudes 
 climates so strangely difierent are known not to be per
 
 76 LECTURES ON GEOLOGY. 
 
 manent causes; temperature is found to depend on the 
 disposition of land and sea, and the position, not of the 
 geographical pole, which is single and centrical in each 
 hemisphere, but of the pole of greatest cold, which, in at 
 least the northern hemisphere, is double, and not centri- 
 cal, — Asia having one, and America another; and if, as 
 is generally held, there be a correspondence amounting 
 almost to identity between the poles of greatest cold and 
 the magnetic poles, then these poles are not fixed, but 
 oscillating. Nor are we left to infer on merely general 
 grounds that the cliiuate of our country may have been at 
 one time greatly more severe than it is now. There is 
 also zoological evidence that it roas greatly more severe.- 
 It is a curious and significant fact, that the group of shells 
 found in the boulder-clay, resting over the scratched and 
 grooved rocks, and accompanying the scratched and pol- 
 ished pebbles, is essentially a boreal or semi-arctic group. 
 This little shell from the boulder-clay of Caithness- — the 
 Trophon scalariforniis or Fusus scalariformis, which, 
 from its small size, seems to have escaped the fate that 
 crushed its lai"ger contemporaries into fragments — is not 
 now found living on our coasts, though it still exists in 
 considerable abundance in the seas of Greenland; and sev- 
 eral of its neighbors in the clay, such as Tellina proxima 
 and Astarte Borealis^ are of the same noi'thern character. 
 Nay, in cases in which the shells of the boulder-clay still 
 live in our seas, we find those of a northern character, such 
 as the Cyjyrina IslancUca^ that, though not rare on the 
 shores of Scotland, is vastly more abundant on those of 
 Iceland, occurring, not in the present British, but in the 
 present Icelandic proportions. The Cyprina Islandica is 
 one of the most common shells of the clay, and, as its 
 name testifies, one of the most common shells of Iceland ;
 
 LECTURES ON GEOLOGY. 77 
 
 but it is by no means one of the most common shells at 
 the present time of our Scottish coasts. The shells of the 
 boulder-clay correspond in the group, not to the present 
 shells of Scotland, but to the present shells of Iceland and 
 the Northern Cape, 
 
 Further, we are not left merely to infer that icebergs 
 could or might have grooved and worn down the rocks of 
 the country : we learn from Sir Charles Lyell — unques- 
 tionably a competent observer — that he caught icebergs 
 almost in the very fact of grooving and wearing down 
 similar rocks. In his first work of " Ti-avels through the 
 United States," he describes a visit which he paid to the 
 coast of Nova Scotia, near Cape Blomidon: "As I was 
 strolling along the beach," he says, " at the base of a line 
 of basaltic cliffs, which rise over ledges of soft sandstone, 
 I stopped short at the sight of an unexpected phenom- 
 enon. The solitary inhabitant of a desert island could 
 scarcely have been more startled by a human footprint in 
 the sand than I was on beholding some recent furrows on 
 a ledge of sandstone under my feet, the exact counterpart 
 of those grooves of ancient date which I have so often 
 
 attributed to glacial action On a recently formed 
 
 ledge I saw several straight furrows half an inch broad, 
 some of them very nearly parallel, others slightly diverg- 
 ent ; and, after walking about a quarter of a mile, I found 
 another set of similar furrows, having the same general 
 direction Avithin about five degrees ; and I made up my 
 mind that, if these grooves could not be referred to the 
 modern instrumentality of ice, it would throw no small 
 doubt on the glacial hypothesis. When I asked my guide, 
 a peasant of the neighborhood, whether he had ever seen 
 much ice on the spot where we stood, the heat was so ex- 
 cessive (for we were in the latitude of the south of France, 
 
 7*
 
 78 LECTURES ON GEOLOGY. 
 
 45 degrees north) that I seemed to be patting a btrange 
 question. lie replied, that in the preceding winter [that 
 of 1841] he had seen the ice, in spite of the tide, which 
 ran at the rate of ten miles an hour, extending in one un- 
 interrupted mass from the shore where we stood, to the 
 opposite coast of Parrsborough, and that the ice- blocks, 
 heaped on each other and frozen together, or packed at 
 the foot of Cape Blomidon, were often fifteen feet thick, 
 and were pushed along, when the tide rose, over the sand- 
 stone ledges. He also stated that fragments of the black 
 stone which fell from the summit of the cliff — a pile of 
 which lay at its base — were often frozen into the ice, and 
 moved along with it. And I have no doubt that the hard- 
 ness of these gravers, firmly fixed in masses of ice, which, 
 though only fifteen feet thick, are often of considerable 
 horizontal extent, has furnished sufficient pressure and me- 
 chanical power to groove the ledges of soft sandstone." 
 
 Thus fir Sir Charles. The boulder-clay is found in 
 Scotland from deep beneath the sea-level, where it forms 
 the anchoring ground of some of our finest harbors, to the 
 height of from six to nine hundred feet along our hill- 
 sides. The travelled boulders to which it owes its name 
 have been found as high as fourteen hundred feet. Up to 
 the highest of these heights icebergs at one time operated 
 upon our Scottish rocks. Scotland, therefore, must in that 
 icy age have been submerged to the highest of these 
 heights. It must have existed as three groups of islands, — 
 the Cheviot, or southern group ; the Grampian, or middle 
 group ; and the Ben Weavis, or northern group. 
 
 Let me next advert to a peculiarity in the direction of 
 the icebei-gs which went careering at this period over the 
 submerged land. As shown by the lines and furrows 
 which they have graven upon the rocks, their general
 
 LECTURES ON GEOLOGY. 79 
 
 course, with a few occasional divergences, — effects appa- 
 rently, of the line of the greater valleys, — was from west 
 to east. It is further a fact, exactly correspondent in the 
 evidence which it bears, that the ti"ap eminences of the 
 country — eminences of hard rock rising amid districts of 
 soft sandstone, or still softer shale — have generally at- 
 tached to their eastern sidef sloping tali of the yielding 
 strata out of which they rise, and which have been washed 
 away from all their other sides. Every larger stone in a 
 water-course, after the torrent fed by a thunder-shower 
 has just subsided, shows, on the same principle, its trail of 
 sand and shingle piled up behind it — sand and shingle 
 which kept it from being swept away ; and the simple ef- 
 fect, when it occurs on the large scale, is known to the 
 geologist as the phenomenon of " Crag and tail." The 
 rock upon which Edinburgh Castle stands, existing as the 
 " crag" and the sloping ridge which extends from the cas- 
 tle's outer moat to Holyrood, existing as the tail, may be 
 cited as a familiar instance. We find the same phenom- 
 enon repeated in the Calton Hill, and in various other 
 eminences in the neigliborhood ; as also in the Castle Hill 
 of Stirling. And in all these, and in many other cases, the 
 tail which the crag protected is turned towards the east, 
 indicating that the current which in the lapse of ages 
 scooped out the valleys at the sides of the protecting 
 crags, and in many instances formed, by its eddies, hollows 
 in advance of them, just as we find hollows in advance of 
 the larger stones of the water-course of my illustration, 
 was a current which flowed from the west. The testi- 
 mony of the ice-grooved rocks, and of the eminences 
 composed of crag and toil, bear, we see, in this same line. 
 Now, this westerly direction of the current seems to be 
 exactly that which, I'easoning from the permanent phe-
 
 80 LECTURES OX GEOLOGY. 
 
 nomena of nature, might be premised. Tliere must have 
 been trade winds in every period of the world's history, in 
 which the earth revolved from west to east on its axis ; 
 and with trade winds the accompanying drift current. 
 And, of consequence, ever since the existence of a great 
 western continent, stretching far from south to north, 
 there must have been also a gnlf stream. The waters 
 heaped up against the coasts of this western continent at 
 the equator by the drift current ever flowing westwards, 
 must have been always, as now, returning eastwards in 
 the temperate zone, to preserve the general level of the 
 ocean's sui-face. Ever, too, since winter took its place 
 among the seasons, there must have been an arctic current. 
 The ice and snows of the higher latitudes, that accumu- 
 lated during the winter, must have again melted in spring, 
 and early summer ; and a current must in consequence 
 have set in as the seasons of these came on, just as we 
 now see such a current setting in, in these seasons, in both 
 hemispheres, wliich bears the ice of the antarctic circle far 
 towards the north, and the ice of the aictic circle far to- 
 wards the south. The point at which, in the existing state 
 of things, the gulf stream and the arctic current come in 
 contact is that occupied by the great bank of Newfound- 
 land ; and by some the very existence of the bank has 
 been attributed to their junction, and to the va§t accumu- 
 lation of gravel and stone cast down year after year from 
 the drift ice to the bottom, where these two great tides 
 meet and jostle. Be this as it may, the number of boul- 
 ders and the quantity of ])ebbles and gravel strewed over 
 the bottom of the western portions of the Atlantic, in the 
 line of the arctic current, from the confines of Baflhi's Bay 
 up to the forty-fifth degree of north latitude, must be alto- 
 gether enormous. Captain Scoresby counted no fewer
 
 LECTURES OS GEOLOGY. 81 
 
 than five hundred icebergs setting out on their southern 
 voyage on the arctic current at one time. And wherever 
 there are shallows on which these vast masses catch the 
 bottom, or grate over it, — shallows of from thirty to a 
 hundred fathoms Avater, — we may safely premise that at 
 the present time there is a boulder-clay in the course of 
 formation, with a scratched and polished sui-face of rock 
 lying beneath it, and containing numerous pebbles and 
 boulders striated longitudinally. That the point where 
 the gulf and arctic currents come in contact should now 
 lie so far to the west, is a consequence of the jDresent dis- 
 position of the arctic and western continents, — pei'haps 
 also of the present position of the magnetic pole. A dif- 
 ferent arrangement and position would give a different 
 point of meeting ; and it is as little improbable that they 
 should have met in the remote past some two or three 
 hundred miles to the west of what is now Scotland, as that 
 in the existing period they should meet some two or three 
 hundred miles to the east of what is now Newfoundland. 
 The northern current would be deflected by the more poAV- 
 erful gulf stream into an easterly course, and would go 
 sweeping over the submerged land in the direction indi- 
 cated by the grooves and scratches, bearing with it every 
 spring its many thousand gigantic icebergs, and its fields 
 of sheet-ice many hundred square miles in extent. And 
 these, armed beneath with great pebbles and boulders, or 
 finding many such resting at the bottom, by grinding 
 heavily along the buried surface, — like the rafts of my 
 illustration along the bed of the river, — would gradually 
 wear down the upper strata of the softer formations, leav- 
 ing the clay which they had thus formed to be deposited 
 over, and a little to the east of, the rocks that had pro- 
 duced it. It is further in accordance with this theory, that
 
 82 LECTURES ON GEOLOGY. 
 
 in Scotland generally, the deeper deposits of the boulder- 
 clay occur on the eastern line of coast. The cutler, in 
 whetting a tool with water on a flat Turkey stone, drives 
 the gray, milky dressings detached by the friction of the 
 steel from the solid mass, to the end of the stone farthest 
 from himself, and there they accumulate thick in the direc- 
 tion of the stroke. And so it is here. The rubbings of 
 the great Scotch whetstone, acted upon by the innumer- 
 able gravers and chisels whetted upon it, and held down 
 or steadied by the icebergs, have been carried in the east- 
 erly direction of the stroke, and deposited at the further, 
 that is to say, the eastern, end of the stone. 
 
 But fearing I have already too much trespassed on your 
 time and patience, I shall leave half told tor the present 
 the story of the Pleistocene pei'iod in Scotland. If, in- 
 stead of presenting it to you as ?_ piece of clear, condensed 
 narrative, I have led you darkly to grope your way 
 through it by a series of fatiguing inductions, you will, I 
 trust, sustain my apology, when I remind you that this 
 dreary ice-epoch in the history of our country, still forms 
 as debateable a terj'a incognita to the geologist as the 
 dreary ice-tracts which surround the pole do to the ge- 
 ographer. We have been threading our twilight way 
 through a diflicult North-West Passage ; and if our prog- 
 ress has been in some degree one of weariness and fatigue, 
 we must remember that without weariness and fatigue no 
 voyager ever yet exj^lored 
 
 " The ice-locked secrets of that hoaiy deep 
 Where fettered streams and frozen continents 
 Lie dark and wild, beat with perpetual storm 
 Of whirlwind and dire hail." 
 
 " We might expect," says Professor Sedgwick, "that as we 
 come close upon living nature, the characters of our old
 
 LECTURES ON GEOLOGY. 88 
 
 records would grow legible and clear. But just where we 
 begin to enter on the history of the j^hysical changes going 
 on before our eyes, and in which we ourselves bear a part, 
 our chronicle seems to fail us: a leaf has been torn out 
 from Nature's book, and the succession of events is almost 
 hidden from our eyes." Now, it is to this age of the drift- 
 gravels and the boulder-clay that the accomplished Pro- 
 fessor here refers, as represented in the geologic record by 
 a torn page ; and though we may be disposed to view it 
 rather as a darkened one, — much soiled, but certainly not 
 awanting, — Ave must be content to bestow on its dim, half- 
 obliterated characters, more time and care than suffice for 
 the perusal of whole chapters in the earlier books of our 
 history. And so, casting myself on your forbearance, I 
 shall take up the unfinished story of the Pleistocene period 
 in Scotland in my next addiess
 
 LECTURE SECOND. 
 
 Problem first propounded to the Author in a Quarry —The Quarry's Two Depos- 
 its, Old lied Sandstone and Boulder-Clay —The Boulder-Clay formed while the 
 Land was subsiding — The Grooviugs and Polishings of the Rocks in the Lower 
 Parts of the Country evidences of the fact — Sir Charles Lyell's Observations 
 on the Canadian Lake District — Close of the Boulder-Clay Kecord in Scotland 
 
 — Its Continuance in Enf;land into the Pliocene Ages— The Trees and Animals 
 of the Pre-Glacial Periods — Elephants' Tusks found in Scotland and England 
 regarded as the Remains of (J iants— Legends concerning them — Marine De- 
 posits beneath the Pre-Glacial Forests of England — Objections of Theologians 
 to the Geological Theory of the Antiquity of the Earth and of tlie Human 
 Race considered — Extent of the Glacial Period in Scotland — Evidences of 
 Glacial Action in Glencoe, Gareloch, and the Highlands of Sutherland — Sce- 
 nery of Scotland owes its Characteristics to Glacial Action — The Period of 
 Elevation which succeeded the Period of Subsidence — Its Indications in 
 Raised Beaches and Subsoils — How the Subsoils and Brick Clays were formed 
 
 — Their Economic Importance — Boulder-Stones interesting Features in the 
 Landscape —Their prevalence in Scotland — The more remarkable Ice-trav- 
 elled Boulders described — Anecdotes of the " Travelled Stone of Petty " and 
 the Standing Stone of Torribal — Elevation of the Land during the Post-Ter- 
 tiary Period which succeeded the Period of the Boulder-Clay — The Alpine 
 Plants of Scotland the Vegetable Aborigines of the Country — Panoramic 
 View of the Pleistocene and Post-Tertiary Periods — Modern Science not 
 adverse to the Development of the Imaginative Faculty. 
 
 I REMEMBER, as distinctly as if I had quitted it but yes- 
 terday, the quarry in which, some two-and-thirty years 
 ago, I made my first acquaintance with a life of toil and 
 restraint, and at the same time first broke ground as a 
 geologist. It formed a section about thirty feet in height 
 by eighty or a hundred in length, in the front of a furze- 
 covered bank, a portion of the old coast line ; and pre- 
 sented an under bar of a deep-red sandstone arranged in 
 nearly horizontal strata, and au upper bar of a pale-red
 
 LECTURES ON GEOLOGY. 85 
 
 clay roughened by projecting pebbles and boulders. Both 
 deposits at the time were almost equally unknown to the 
 geologist. The deep-red sandstone beneath formed a por- 
 tion of that ancient Old Red system which represents, as 
 is now known, the second great period of vertebrate exist- 
 ence on our planet, and which has proved to the palteon- 
 tologist so fertile a field of wonders : the psiie clay above 
 was a deposit of the boulder-clay, resting on a grooved 
 and furrowed surface of rock, and containing in abundance 
 its scratched and polished pebbles. Old Red Sandstone 
 and boulder-clay ! a broad bar of each ; — such was the 
 compound problem propounded to me by the Fate that 
 dropped me in a quarry ; and I gave to both the patient 
 study of years. But the older deposit soon became frank 
 and communicative, and yielded up its organisms in abun- 
 dance, which furnished me with many a curious little anec- 
 dote of their habits when living, and of the changes which 
 had passed over them when dead ; and I was enabled, 
 with little assistance from brother geologists, to give a his- 
 tory of the system to the world more than ten years ago. 
 The boulder-clay, on the contrary, remained for years in- 
 vincibly silent and sullen. I remember a time when, after 
 passing a day under its barren scaurs, or hid in its precip- 
 itous ravines, I used to feel in the evening as if I had been 
 travelling under the cloud of night, and had seen nothing. 
 It was a morose and taciturn companion, and had no spec- 
 ulation in it. I might stand in front of its curved preci- 
 pices, red, yellow, or gray (accoi'ding to the prevailing 
 color of the rocks on which it rested), and might mark 
 their water-rolled boulders of all kinds and sizes sticking 
 out in bold relief from the surface, like the protuberances 
 that roughen the rustic basements of the architect ; but I 
 had no *' Open Sesame " to form vistas through them into 
 
 8
 
 86 LECTURES ON GEOLOGY. 
 
 the recesses of the past. And even now, when I have, 
 I think, begun to understand the boulder-clay a little, and 
 it has become sociable enough to indulge me with occa- 
 sional glimpses of its early history in the old glacial period, 
 — glimpses of a half-submerged land, and an iceberg-mot- 
 tled sea, turbid with the comminuted debris of the rocks 
 below, — you will see how very much I have had to borrow 
 from the labors of others, and that, in worming ray way 
 into its secret, there are obscure recesses within its pre- 
 cincts into which I have failed to penetrate. Let us now, 
 however, resume its half-told story. 
 
 There are appearances which lead us to conclude, that 
 during the formation and deposition of the boulder-clay, 
 what is now Scotland was undergoing a gradual subsid- 
 ence, — gradually foundering amid the waves, if I may so 
 speak, like a slowly-sinking vessel, and presenting, as cen- 
 tury succeeded century, hills of lower and yet lower alti- 
 tude, and an ever lessening area. I was gratified to find, 
 that when reasoning out the matter for myself, and arriv- 
 ing at this conclusion from the examination of one special 
 set of data, Mr. Charles Darwin was arriving at the same 
 conclusion from the consideiMtion of a second and entirely 
 difierent set; and Sir Charles Lyell — from whom, on the 
 publication of my views in the "Witness" newspaper some 
 four years since, I received a kind and interesting note on 
 the subject — had also arrived at the same conclusion — 
 North America being the scene of his observations — from 
 the consideration of yet a third and equally distinct set. 
 And in the "Geological Journal" for the present year, I 
 find Mr. Joshua Trimmer and Mr. Austin arriving, from 
 evidence equally independent, at a similar finding. We 
 have all come to infer, in short, that previous to the Drift 
 period the land had stood at a comparatively high level, —
 
 LECTURES ON GEOLOGY. 87 
 
 perhaps higlier tlian it does now; that ages of depression 
 came on, during wliich the hind sank many hundred feet, 
 and the sea rose higli on the hill-sides ; and that during 
 these ages of depression the boulder-clay was formed. 
 Let me state briefly some of the considerations on which 
 we found. 
 
 The boulder-clay, I thus reasoned with myself, is gener- 
 ally found to overlie more deeply the lower parts of the 
 country than those higher parts which approach its upper 
 limit ; and yet the rocks on which it rests, in some local- 
 ities to the depth of a hundred feet at even the level of 
 the sea, bear as decidedly their groovings and polishings 
 as those on which, eight hundred feet over the sea-level, 
 it reposes to but the depth of a yard or two. Now, had 
 a rising land been subjected jiieceraeal to the grinding 
 action of the icebergs, this would not have been the case. 
 The higher rocks first subjected to their action would of 
 course bear the groovings and furrowings ; but the argil- 
 laceous dressings detached from them in the process, mixed 
 with the stones and pebbles which the ice had brought 
 along with it, would necessarily come to be deposited in 
 tlie form of boulder-clay on the lower rocks ; and ere these 
 lower rocks could be brought, by the elevation of the 
 land, within reach of the grinding action of the icebergs, 
 they would be so completely covered up and shielded by 
 the deposit, that the bergs would fail to come in contact 
 with them. They would go sweeping, not over the rocks 
 themselves, but over the clay by which the rocks had been 
 covered up ; and so we may safely infer that, had the 
 boulder-clay been formed during an elevating jjeriod, the 
 lower rocks, where thickly covered by the clay, would not 
 be scratched and grooved as we now find them, or, where 
 scratched and grooved, would not be thickly covered by
 
 OS LECTURES ON GEOLOGY. 
 
 the clay. The existing phenomena, deep grooves and 
 polished strife, on rocks overhiid at the present sea-level 
 to a great depth by the boulder-clay, demand for their 
 production the reverse condition of a sinking land, in. 
 "which the lower rocks are first subjected to the action of 
 the icebergs, and the higher rocks after them. The quar- 
 rier, Avhen he has to operate on some stratum of rock on a 
 hill-side, has to commence his labors below, and to throw 
 the rubbish which he forms behind him, leaving an open 
 face in front; for, were he to reverse tlie process, and com- 
 mence above, the accumulating debris, ever seeking down- 
 wards, would at length so choke up the working as to 
 arrest his labors. And such, we infer from the work done, 
 must have been the course of operations imposed by the 
 conditions of a sinking land on the icebergs of the glacial 
 period : they began their special course of action at the 
 hill-foot, and operated upon its sui-face upwards as the 
 sea arose. Again, Mr. Darwin's reasonings Avere mainly 
 founded on the significant fact, that in numerous instances 
 travelled boulders of the ice j^eriod may be found on levels 
 considerably higher than those of the rocks from which 
 they were originally torn. And though cases of transport 
 from a lower to a higher level could and would take place 
 during a period of sul)sidence, when the sea was rising or 
 the land sinking, it is impossible that it could have taken 
 place during an elevating period, Avhen the sea was sink- 
 ing or the land rising.^ A flowing sea, to use a simple 
 illustration, frequently carries shells, pebbles, and sea-weed 
 from the level of ebb to the level of flood; — it brings 
 them fi'om a low to a high level : whereas an ebbing sea 
 
 ^ Sec Mr. Trimtner'.s last paper on Boulder-Clays, " Journal of the Geo- 
 lof;ical Society," May, 18.18, p. 171. — W. S.
 
 LECTURES ON GEOLOGY. 89 
 
 can but reverse the process, by bringing them from a high 
 level to a low. 
 
 For the facts and reasonings of Sir Charles Lyell on the 
 subject I must refer you — as they are incapable of being 
 abridged without being injured — to that portion of his 
 first work of Travels in America which treats of the Cana- 
 dian Lake District. But the following are his conclusions: 
 "J^u'S?," he says, " the country acquired its present geo- 
 graphical configuration, so far as relates to the older rocks, 
 under the joint influence of elevating and denuding oper- 
 ations. Secondly, a gradual submergence then took place, 
 bringing down each part of the land successively to the 
 level of the waters, and then to a moderate depth below 
 them. Large islands and bergs of floating ice came fi-om 
 the north, which, as they grounded on the coast and on 
 shoals, pushed along all loose materials of sand and peb- 
 bles, broke ofi" all angular and projecting points of rock, 
 and, when fragments of hard stone were frozen into their 
 lower sui'faces, scooped out grooves in the subjacent solid 
 strata. Thirdly, after the surface of the rocks had been 
 smoothed and grated upon by the passage of innumerable 
 icebergs, the clay, gravel, and sand of the Drift were de- 
 posited; and occasionally fragments of rock, both large 
 and small, which had been frozen into glaciers, or taken 
 up by coast-ice, were dropped here and there at random 
 over the bottom of the ocean, wherever they happened to 
 be detached from the melting ice. Finally, the period of 
 reelevation arrived, or of that intermittent upward move- 
 ment in which the old coast lines were excavated and the 
 ancient sand bars or osars laid down." Such are the con- 
 clusions at which Sir Charles Lyell arrived a few years 
 since respecting the Canadian Lake District ; and he 
 states, in the note to which I have referred, that he has 
 
 8*
 
 90 LECTURES ON GEOLOGY. 
 
 ever since been applying them to Scotland. Our country, 
 during the chill and dreary period of the boulder-clay, 
 seems to have been settling down into the waves, like the 
 vessel of some hapless Arctic explorer struck by the ice 
 in middle ocean, and sinking by inches amid a wild scene 
 of wintry desolation. 
 
 There are a few detached localities in Scotland where 
 the remains of beds of stratified sand and gravel have 
 been detected underl}^ng the boulder-clay; and in some 
 of these in the valley of the Clyde, Mr, Smith, of Jordan- 
 hill, found, on a late occasion, shells of the same semi- 
 arctic character as those which occur in the clay itself. 
 And with these stratified beds the record in Scotland 
 closes; whereas in England we find it carried interest- 
 ingly onward from the Pleistocene period, first into the 
 newer, and then into the older. Pliocene ages. I stated 
 incidentally in my former address, that some of the mosses 
 of the sister kingdom, unlike those of our own country, 
 are older than the Drift period ; and, from the existence of 
 these under the Drift gravels and brown clay, it has been 
 inferred by Mr. Trimmer, that as the trees which enter 
 into their composition grew upon the surface of what is 
 now England, where they now lie, previous to the period 
 of the boulder-clay, and as the boulder-clay is, as shown 
 by its remains, decidedly marine, it must have been depos- 
 ited during a period of depression, when what had been a 
 forest-bearing surface was lowered beneath the level of the 
 sea. None of the trees of these ancient pre-glacial forests 
 seem to be of extinct species; tlie birch and Scotch fir 
 are among their commonest forms, especially the fir. I 
 find it stated, however, as a curious fact, that along with 
 these, the Abies Excelso,, or Norwegian spruce-pine, is 
 found to occur, — a tree which, though introduced by man
 
 LECTURES ON GEOLOGY. 91 
 
 into our country, and now not very rare in our woods, has 
 not been of indigenous growth in any British forest since 
 the times of the boulder-clay. Though the species con- 
 tinued to live in Norway, it became extinct in Britain ; 
 and it has been suggested, that as it was during the Drift 
 period that it disappeared, it may have owed its extirpa- 
 tion to the depression of the land, while its contemj^oraries 
 the birch and fir were preserved on our northern heights. 
 When this Norwegian pine flourished in Britain, the island 
 was inhabited by a group of quadru2:)eds now never een 
 associated, save perhaps in a menagerie. Mixed with the 
 remains of animals still native to our country, such as the 
 otter, the badger, and the red deer, there have been found 
 skeletons of the Lagomy, or tailless hare, now an inhab- 
 itant of the cold heights of Siberia, and horns of the rein- 
 deer, a species now restricted in Europe to northern 
 Scandinavia, and those inhospitable tracts of western 
 Russia that border on the Arctic Sea. And with these 
 boreal forms thei'e were associated, as shown by their bones 
 and tusks, the elephant, the rhinoceros, and the hippopota- 
 mus, — all, however, of extinct species, and fitted for liv- 
 ing under widely different climatal conditions from those 
 essential to the well-being of their intertropical congeners.^ 
 Scotland, though it has proved much less rich than Eng- 
 land in the remains of the early Pleistocene mammals, has 
 furnished a few well-attested elephantine fossils. In the 
 summer of 1821, in the course of cutting the Union Canal, 
 there was found in the boulder-clay near Falkirk, on the 
 Clifton Hall property, about twenty feet from the surface, 
 
 1 The true mammoth, with the tichorine rhinoceros and the musk buf- 
 falo, are the leading: types of the mammalian fauna of the Glacial Drift 
 epoch. The remains of hippopotamus would be washed out of older beds. 
 — W. S.
 
 92 LECTURES ON GEOLOGY. 
 
 a large portion of the tusk of an elephant, three feet three 
 inches in length, and thirteen inches in circumference ; and 
 such was its state of keeping when first laid open, that it 
 was sold to an ivory-turner by the laborers that found it, 
 and was not rescued from his hands until a portion of it 
 had been cut up for chessmen. Two other elephants' 
 tusks were found early in 1817, at Kilmaurs,^ in Ayrshire, 
 on a property of the Earl of Eglinton, — one of them so 
 sorely decayed that it could not be removed ; but a portion 
 of the other, with the rescued portion of the Falkirk tusk, 
 may be seen in the Museum of our Edinburgh University, 
 which also contains, I may here mention, the horn of a 
 rhinoceros, found at the bottom of a morass in Forfarshii'e, 
 but which, in all jarobability, as it stands alone among the 
 organisms of our mosses, had been washed out of some 
 previously formed deposit of the Drift period. Scotland 
 seems to have furnished several other specimens of ele- 
 phantine remains; but as they were brought to light in 
 ages in which comparative anatomy was unknown, and 
 men believed that the human race had been of vast 
 strength and stature in the primeval ages, but were fast 
 sinking into dwarfs, they wei-e regarded as the remains of 
 giants. Some of the legends to which the bones of these 
 supposed giants served to give rise in England, occupy a 
 place in the first chapter of the country's history, as told 
 by the monkish chroniclei's, and have their grotesque but 
 widely-known memorials in Gog and Magog, the wooden 
 giants of Guildhall : our Scottish legends of the same class 
 are less famous; but to one of their number — charged 
 
 1 At a later period (December 1829), similar elephantine tusks were 
 found thirty-four feet beneath the surface, in boulder-clay overlying the 
 quarry of Grcenhill, also in Kilmaurs parish; and they may now be seen 
 in the Hunterian Museum, Glasgow.
 
 LECTURES ON GEOLOGY. 93 
 
 with an argument in behalf of the temperance cause of 
 which our friends the teetotalers have not yet availed 
 themselves — I may be permitted briefly to refer, in the 
 words of one of our elder historians. " In Murray land," 
 says the believing Hector Boece, "is the Kirke of Pette, 
 quhare the bones of Litell Johne remainis in gret admira- 
 tion of pepill. He hes bene fourtene feet of hicht, with 
 squaire membres efFering thairto. Six yeirs afore the 
 coming of this work to licht (1520), we saw his henche 
 bane, as meikle as the haill banes of ane manne ; for we 
 schot our arme into the mouthe thairof ; be quhilk appeirs 
 how Strang and squaire pepill greu in oure regeoun afore 
 thay were effeminat with lust and intemperance of mouthe." 
 Under these pre-glacial forests of England there rests a 
 marine deposit, rich in shells and quadrupedal remains, 
 known as the Norwich or Mammaliferous Crag; and be- 
 neath it, in turn, lie the Red and Coralline Crags, — mem- 
 bers of the Pliocene period. In the Mammaliferous Crag 
 there appear a few extinct shells, blent with shells still 
 common on our coasts. In the Red Crag the number of 
 extinct species greatly increases, rising, it is now estimated, 
 to thirty per cent, of the whole ; while in the Coralline 
 Crag the increase is greater still, the extinct shells averag- 
 ing about forty per cent.^ In these deposits some of our 
 best known molluscs appear in creation for the first time. 
 The common edible oyster {Ostrea edidis) occurs in the 
 Coralline Crag, but in no older formation, and with it the 
 great pecten {Pecten maximus)^ the horse mussel {Modi- 
 ola vulgaris), and the common whelk {Buccinum unda- 
 turn). Other equally well-known shells make their advent 
 
 1 The known species of shells in the Coralline Cra?^ amount to three 
 hundred and forty. Of these, seventy-three are living British species 
 See Woodward's " Manual," part iii. p. 421. — W. S.
 
 94 LECTURES ON GEOLOGY. 
 
 at a still later period ; the common mussel {Mytilus echc- 
 lis), the common periwinkle {Littoriaa littorea), and, in 
 Bntain at least, the dog-whelk (Picr-piira lapilhcs), firsi 
 appear in the overlying Red Crag, and are not known in 
 the older Coralline formation. By a certain very extended 
 period, represented by the Coralline Crag, the edible oyster 
 seems to be older than the edible mussel, and the common 
 whelk than the common periwinkle ; and I call your spe- 
 cial attention to the fact, as representative of a numerous 
 class of geological facts that bear on certain questions of 
 a semi-theological character, occasionally mooted in the 
 religious periodicals of the day. There are few theolo- 
 gians worthy of the name who now hold that the deduc- 
 tions of the geologists regarding the earth's antiquity are 
 at variance with the statements of Scripture respecting 
 its first creation, and subsequent preparation for man. 
 But some of them do seem to hold that the scheme of 
 reconciliation, found sufficient when this fact of the earth's 
 antiquity was almost the only one with which we had to 
 grapple, should be deemed sufiicient still, when science, in 
 its onward progress, has called on us to deal with this new 
 fact of the very unequal antiquity of the plants and ani- 
 mals still contemporary with man, and with the further 
 fact, that not a few of them must have been living upon 
 the earth thousands of years ere he himself was ushered 
 upon it, — facts of course wholly incompatible with any 
 scheme of interpretation that would fix the date of their 
 first appearance only a few natural days in advance of that 
 of his own. We have no good reason to hold that the 
 human species existed upon earth during the times of the 
 boulder-clay : such a belief would conflict, as shown by the 
 antiquity of the ancient and existing coast lines, with our 
 received chronologies of the race. But long previous to
 
 LECTURES ON GEOLOGY. 95 
 
 these times, the Norwegian spruce pine and the Scotdi fir 
 were natives of the pre-glacial forests of onr country ; at 
 even an earlier period the common periwinkle and edible 
 mussel lived in tlie seas of the Red Crag deposits ; and at 
 a still earlier time, the great j^ecten, the whelk, and the 
 oyster, in those of the Coralline Crag. We can now no 
 more hold, as geologists, that the plants and animals of 
 the existing creation came into being only a few hours 
 or a few days previous to man, than that the world itself 
 came into being only six thousand years ago ; and we do 
 think we have reason to complain of theologians who, 
 ignorant of the facts with which we have to deal, and in 
 no way solicitous to acquaint themselves with them, set 
 themselves coolly to criticize our well-meant endeavors to 
 reconcile the Scrijjture narrative of creation with the more 
 recent findings of our science, and who pronounce them 
 inadmis-sible, not because they do not effect the desired 
 reconciliation, but simply because they are new to theol- 
 ogy. They should remember that the difficulty also is 
 new to theology; that enigmas cannot be solved until 
 they are firet propounded ; that if the riddle be in reality 
 a new one, the answer to it must of necessity be new like- 
 wise ; and as this special riddle has been submitted to the 
 geologists when the theologians wei'e unaware of its exist- 
 ence, it must not be held a legitimate objection, that geolo- 
 gists, who feel that they possess, as responsible men, a stake 
 in the question, should be the first to attempt solving it. 
 If, however, it be, as I suspect, with our facts, not with our 
 schemes of reconciliation, that the quarrel in reality lies, 
 — if it be, in particular, with the special fact of the une- 
 qual antiquity of the existing plants and animals, and the 
 comparatively recent introduction of man, — I would fain 
 urge the objectors to examine ere they decide, and not
 
 96 LECTURES ON GEOLOGY. 
 
 rashly and in ignorance to commit themselves against 
 truths which every day must render more palpable and 
 clear, and which are destined long to outlive all cavil and 
 opposition. 
 
 With respect to the antiquity of our race, we have, as I 
 have said, no good grounds to believe that man existed 
 upon the earth during what in Britain, and that jDortion 
 of the continent which lies under the same lines of lati- 
 tude, were the times of the boulder-clay and Di-ift gravels. 
 None of the human remains yet found seem more ancient 
 than the historic period, in at least the older nations ; it is 
 now held that the famous skeletons of Guadaloupe* be- 
 longed to men and women who must have lived since the 
 discovery of America by Columbus ; and if in other jjarts 
 of the world there have been detected fragments of the 
 human frame associated with those of the long extinct 
 animals, there is always reason to conclude that they owe 
 such j^roximity to that burying propensity to which I have 
 already adverted, or to accidents resulting from it, and not 
 to any imaginary circumstance of contemporarity of exist- 
 ence. If man buries his dead in the Gault or the London 
 Clay, human remains will of course be found mingled with 
 those of the Gault or the London Clay; but the evidence 
 furnished by any such mixture will merely serve to show, 
 not that the existences to which the remains belonged had 
 lived in the same age, but simply that they had been 
 deposited in the same formation. Nor can I attach much 
 value to the supposed historic records of countries such as 
 Egypt, in which dynasties are repi'esented as having flour- 
 ished thousands of years ere the era of Abraham. The 
 chronicles of all nations have their fxbulous introductory 
 portions. No one now attaches any value to the record 
 of the eighty kings that are said to have reigned in Scot-
 
 LECTURES ON GEOLOGY. 97 
 
 land between the times of Fergus the First and Constan- 
 tine the Bold ; or to that portion of old English history 
 which treats of the dynasty of Brutus the Parricide, or 
 his wars with the giants. All the ancient histories have, 
 as Buchanan tells us, in disposing of the English claims, 
 their beginnings obscured by fable ; nor is it probable that 
 the Egyptian history is an exception to all the others, or 
 that its laboriously inscribed and painfully interpreted 
 hieroglyphics were more exclusively devoted to the re- 
 cording of real events than characters simpler of fornvind 
 easier of perusal. If, as some contend, man has been a 
 denizen of this world for some ten or twelve thousand 
 yeai-s, what, I would ask, was he doing the first five or six 
 thousand? It was held by Sir Isaac Newton, that the 
 species must have been of recent introduction on earth, 
 seeing that all the great human discoveiies and inventions, 
 such as letters, the principles of geometry and arithmetic, 
 printing, and the mariner's compass, lie within the historic 
 period. The mind of man could not, he inferred, have 
 been very long at work, or, from its very constitution, it 
 would have discovered and invented earlier ; and all his- 
 tory and all archaeological research bear out the inference 
 of the philosopher. The older civilized nations lie all 
 around the original centre of the race in Western Asia ; 
 nor do we find any trace of a great city older than Nine- 
 veh, or of a great kingdom that preceded in its rise that 
 of Egypt. The average life of great nations does not 
 exceed twelve, or at most fifteen, hundred years ; and the 
 first great nations were, we find, living Avithin the memory 
 of letters. Geology, too, scarce less certainly than Reve- 
 lation itself, testifies that the last-born of creation was 
 man, and that his appearance on earth is one of the most 
 
 9
 
 98 LECTURES ON GEOLOGY. 
 
 recent events of which it submits the memorials to its 
 votaries. 
 
 But to return : The glacial or ice period in Scotland 
 seems to have extended from the times of the stratified 
 beds, charged with sub-arctic shells, which underlie the 
 boulder-clay, until the land, its long period of depression 
 over, was again rising, and had attained to an elevation 
 less by only fifty or a hundred feet than that which it at 
 present maintains. Such is the height over the sea-level, 
 of the raised beach at Gamrie in Banffshire ; and in it the 
 arctic shells last appear. And to the greatly-extended 
 sub-arctic period in Scotland there belong a class of ap- 
 pearances which have been adduced in suppoi't of a glacial 
 as opposed to an iceberg theory. But there is in reality no 
 antagonism in the case. After examining not a few of 
 our Highland glens, especially those on the north-western 
 coast of the country, I have arrived at the conviction, 
 that Scotland had at one time its glaciers, which, like those 
 of Iceland, descended along its valleys, from its inland 
 heights, to the sea. And as in most cases certain well- 
 marked accompaniments of the true glaciei-, such as those 
 lateral and transverse moraines of detached rock and 
 gravel that accumulate along their sides and at their lower 
 terminations, are wanting in Scotland, it is inferred that 
 great currents must have swept over the country since the 
 period of their existence, and either washed their moraines 
 away, or so altered their character and appearance that 
 they can be no longer recognized as moraines. Of course, 
 this sweeping process might have taken place during that 
 period of profound subsidence when tlie boukler-clay was 
 foimed, and in a posterior period of more partial subsidence, 
 which is held to have taken place at a later time and un- 
 der milder climatal conditions, and which is said to have
 
 LECTURES OX GEOLOGY. 99 
 
 brought down the land to its present level from a considera- 
 bly higher one. In many localities there rests over the true 
 boulder-clay an ai-gillaceous or gravelly deposit, in which 
 the masses and fragments of rock are usually angular, ai>'^ 
 which, even where the boulder-clay is shell-bearing, cor- 
 tains no shells. There are other localities in which a siw^' 
 ilar deposit also underlies the boulder-clay; and these 
 deposits, upper and lower, are in all probability the debris 
 of glaciers that existed in our country during the ice era, 
 — the lower deposit being the debris of glaciers that had 
 existed previous to the glacial period of subsidence, and 
 the upper that of glaciers which had existed posterior to 
 it, and when the land was rising. The evidence is, I think, 
 conclusive, that glaciere there were. I examined, during 
 the autumn of last year, the famous Glencoe, and can now 
 entertain no more doubt that a glacier once descended 
 along the bottom of that deep and rugged valley, filling it 
 up from side to side to the depth of from a hundred and 
 fifty to two hundred feet, than that an actual glacier de- 
 scends at the present day along the valley of the Aar or 
 of the Orindelwald. The higher precipices of Glencoe are 
 among the most rugged in the kingdom : we reach a cer- 
 tain level; and, though no change takes place in the qual- 
 ity of the rock, all becomes rounded and smooth, through 
 the agency, evidently, of the vanished ice river, whose old 
 line of surface we can still point out from the continuous 
 mark on the sides of prccipices, beneath which all is smooth, 
 and above which all is nigged, and whose scratchings and 
 groovings we can trace on the hard porphyry descending 
 towards the Atlantic, even beyond where the sea occuj)ies 
 the bottom of the valley. The lines and grooves running 
 in a reverse direction to those of the icebergs, for their 
 course is towards the west, are distinctly discernible as far
 
 100 LECTURES ON GEOLOGY. 
 
 flown as Ballachulish fei-ry. Similar marks of a great gla- 
 cier in the valley of the Gareloch have been carefully 
 traced and shrewdly interpreted by Mr. Charles M'Laren. 
 But nowhere have I seen the evidence of fflacial action 
 more decided than in the Highlands of Sutherland, over 
 which I travelled last August more than a hundred and 
 fifty miles, for the purpose of observation. There is scarce 
 a valley in that wild region, whether it open towards the 
 northern or western Atlantic, or upon the German Ocean, 
 that in this ungenial period was not cumbered, like the 
 valleys of the upper Alps, by its burden of slowly descend- 
 ing ice. Save where, in a few localities on the lower slopes 
 of the hills, the true boulder-clay appears, almost all the 
 subsoil of the country, where it has a subsoil, is composed 
 of a loose, unproductive glacial debris; almost every 
 prominence on the mountain-sides is rounded by the long- 
 protracted action of the ice; and in many instances the 
 surfaces of the rocks bear'the characteristic groovings and 
 scratchings as distinctly as if it had performed its work 
 upon them but yesterday. Let me, however, repeat the 
 remark, that the iceberg and glacial theories, so far from 
 being antagonistic, ought rather to be regarded as equally 
 indispensable parts of one and the same theory, — parts 
 which, when separated, leave a vast amount of residual 
 phenomena to puzzle and perplex, that we find fully ac- 
 counted for by their conjunction. And why not conjoin 
 them? The fact that more than four thousand square 
 miles of the interior of Iceland are covered by glaciers, is 
 in no degree invalidated by the kindred fiict that its shores 
 are visited every spring by hundreds of thousands of ice- 
 bergs. 
 
 The glaciers of Scotland have, like its icebergs, contrib- 
 uted their distinctive quota to the scenery of the country.
 
 LECTURES ON GEOLOGY. 101 
 
 The smoothed and rounded prominences of the hills, bare 
 and gray amid the scanty lieath, and that often after a sud- 
 den shower gleam bright to the sun, like the sides and 
 bows of windward-beating vessels wet by the spray of a 
 summer gale, form well-marked features in the landscapes 
 of the north-western parts of Sutherland and Ross, espec- 
 ially in the gneiss and quartz-rock districts. The lesser 
 islets, too, of these tracts, whether they rise in some soli- 
 tary lochan among the hills, or in some arm of the sea 
 that deeply indents the coast, still bear the rounded form 
 originally communicated by the ice, and in some instances 
 remind the traveller of huge whales heaving their smooth 
 backs over the brine. Further, we not unfrequently see 
 the general outline of the moiintains affected ; — all their 
 peaks and precipices curved backwards in the direction 
 lohence the glacier descended, and more angular and ab- 
 rupt in the direction toicards which it descended. But 
 it is in those groups of miniature hills, composed of glacial 
 debris, Avhich so frequently throng the openings of our 
 Highland valleys, and which Burns so graphically describes 
 in a single line as 
 
 " Hillocks di'opt in Nature's careless haste," 
 
 that perhaps the most jjleasing remains of our ancient gla- 
 ciers are to be found. They seem to be modified moraines, 
 and usually affect regular forms, resembling in some in- 
 stances the roofs of houses, and in some the bottoms of 
 iipturned ships; and, grouped thick together, and when 
 umbrageous with the graceful biich, or waving from top to 
 base with the liglit fronds of the lady-fern and the bracken, 
 they often compose scenes of a soft and yet wild loveli- 
 ness, from which the landscape gardener might be content 
 to borrow, and which seem to have impressed in a very 
 
 9*
 
 102 LECTURES ON GEOLOGY. 
 
 early age the Celtic imagination. They constitute the 
 fairy Torahans of Highland mythology; and many a curi- 
 ous legend still survives, to tell of benighted travellers 
 who, on one certain night of the yeai-, of ghostly celebrity, 
 have seen open doors in their green sides, wlience gleams 
 of dazzling light fell on the thick foliage beyond, and have 
 heard voices of merriment and music resounding from 
 within ; or Avho, mayhap, incautiously entering, have lis- 
 tened entranced to the song, or stood witnessing the 
 dance, until, returning to the open air, they have found 
 that in what seemed a brief half hour half a lifetime had 
 passed away. There are few of the remoter valleys of the 
 Highlands that have not their groups of fairy Tomhans, 
 — memorials of the age of ice. 
 
 After the lajDse of ages — but who can declare their 
 number? — the period of subsidence represented by the 
 boulder-clay came to a close, and a period of elevation 
 succeeded. The land began to rise ; and there is consid- 
 erable extent of superficial deposits in Scotland which we 
 owe to this period of elevation. It is the main object of 
 the ingenious work of Mr. Robert Chambers on Raised 
 Beaches to show that there were pauses in the elevating 
 process, during which the lines against which the waves 
 beat were hollowed into rectilinear terraces, much broken, 
 it is true, and widely separated in their parts, but that 
 wonderfully correspond in height over extensive areas. 
 It is of course to be expected, that the higher and moi'e 
 ancient the beach or terrace, the more must it be worn 
 down by the action of the elements, especially by the 
 descent of water-courses ; and as the supposed beachies 
 intermediate between the strongly-marked ancient coast 
 line which I have already described at such length, and 
 certain upper lines traceable in the moorland districts of
 
 LECTURES ON GEOLOGY. 103 
 
 the country, occur in an agricultural region, the obliterat- 
 ing wear of the plough has been added to that of the cli. 
 mate. After, however, all fair allowances have been made, 
 there remain great difficulties in the way. I have been 
 jjuzzled, for instance, by the fact that Scotland presents us 
 with but two lines of water-worn caves, — that of the 
 present coast line, and that of the old line immediately 
 above it. Mr, Chambei's enutnerates no fewer than fifteen 
 coast lines intermediate between the old coast line and a 
 coast line about three hundred feet over it ; and in the 
 range of granitic I'ocks which skirt on both sides the en- 
 trance of the Cromarty Frith, there are precipices fully a 
 hundred yards in height, and broadly exposed to the 
 stormy north-east, whose bases bear their double lines of 
 deeply-hollowed caverns. But they exhibit no third, or 
 fourth, or fifth line of caves. Equally impressible through- 
 out their entire extent of front, and with their inclosed 
 masses of chloritic schist and their lines of fixult as thickly 
 set in their brows as in their bases, they yet present no 
 upper stories of caves. Had the sea stood at the fifteen 
 intermediate lines for periods at all equal in duration to 
 those in which it has stood at the ancient or existing coast 
 line, the taller precipices of the Cromarty Sutors would 
 present their seventeen stories of excavations ; and exca- 
 vations in hard granitic gneiss that varied from twenty to 
 a hundred feet in depth would form marks at least as in- 
 delible as parallel roads on the mountain sides, or mounds 
 of gravel and debris overtopping inland plains, or rising 
 over the course of rivers. The want of lines of caves 
 higher than those of the ancient coast line would seem to 
 indicate, that though the sea may have remained long 
 enough at the various upper levels to leave its mark on 
 soft, impressible materials, it did not remain long enough 
 to excavate into caverns the solid rocks.
 
 104. LECTURES ON GEOLOGY. 
 
 But though the rise of the hiud may have been compar- 
 atively rapid, there was quite time enough during the term 
 of upheaval for a series of processes that have given con- 
 siderable variety to the subsoils of our country. Had the 
 land been elevated at one stride, almost the only subsoil 
 of Avhat Ave recognize as the agricultural region of Scot- 
 land would have been the boulder-clay, here and there 
 curiously inlaid with iri'egular patches of sand and gravel, 
 which occur occasionally throughout its entire thickness, 
 and which wei-e pi'obably deposited in the forming mass by 
 icebergs, laden at the bottom with the sand and stones of 
 some sea-beach, on which they had lain frozen until floated 
 off, with their burdens, by the tide. But there elapsed 
 time enough, during the upheaval of the land, to bring its 
 boulder-clay deposits piecemeal under the action of the 
 tides and waves; and hence, appai'ently, the origin of not 
 a few of our lighter subsoils. Wherever the waves act at 
 the present time upon a front of clay, we see a separation 
 of its parts taking place. Its finer argillaceous particles 
 are floated off to sea, to be deposited in the outer depths ; 
 its arenaceous particles settle into sand-beds a little adown 
 the beach ; its pebbles and boulders form a surface stratum 
 of stones and gravel, extending from the base of the scaur 
 to where the surf breaks at the half-tide line. We may 
 see a similar process of separation going on in ravines of 
 the boulder-clay swept by a streamlet. After every shower 
 the stream comes down brown and turbid with the more 
 argillaceous portions of the deposit; accumulations of 
 sand are swej^t to the gorge of the ravine, or cast down in 
 ripple-marked patches in its deeper pools; beds of })ebbles 
 and gravel are heaped up in every inflection of its banks ; 
 and boulders are laid bare along its sides. Now, a separa- 
 tion by a sort of washing process of an analogous charac-
 
 LECTURES ON GEOLOGY. 105 
 
 ter seems to have taken j^lace in the materials of the more 
 exposed portions of the boulder-clay, during the emergence 
 of the land ; and hence, apparently, those extensive beds 
 of sand and gravel which in so many parts of the kingdom 
 exist in relation to the clay as a superior or upper subsoil ; 
 hence, too, occasional beds of a purer clay than that be- 
 neath, divested of a considerable portion of its arenaceous 
 components, and of almost all its pebbles and boulders. 
 This washed clay — a re-formation of the boulder deposit 
 
 — cast down mostly in insulated beds in quiet localities, 
 where the absence of currents suffered the purer particles, 
 held in suspension by the water, to settle, fonns, in Scot- 
 land at least, — with, of coui*se, the exception of the ancient 
 fire-clays of the Coal Measures, — the true brick and tile 
 clays of the agriculturist and architect. There are exten- 
 sive beds of this washed clay within a short distance of 
 Edinburcfh ; and vou might find it no uninteresting em- 
 ployment to compare them, in a leisure hour, with the 
 very dissimilar boulder-clays over which they rest. Unlike 
 the latter, they are finely laminated : in the brick beds of 
 Portobello I have seen thin streaks of coal-dust, and occa- 
 sionally of sand, occurring between the layers ; but it is 
 rare indeed to find in them a single pebble. They are the 
 washings, in all likelihood, of those boulder-clays which 
 rise high on the northern flanks of the Pentlands, and 
 occur in the long, flat valley along which the Edinburgh 
 and GlasgoAV Railway runs, — washings detached by the 
 waves when the land was rising, and which, carried towards 
 the east by the westward, current, were quietly deposited 
 in the lee of Arthur Seat and the neighboring eminences, 
 
 — at that time a small group of islands. The only shells 
 I ever detected in the brick-clay of Scotland occurred in a 
 deposit in the neighborhood of St. Andrew's, of appar-
 
 106 LECTURES ON GEOLOGY. 
 
 ently the same age as the beds at Portobello.^ They were 
 in a bad state of keeping ; but I succeeded in identifying 
 one of the number as a deep-sea Balanus, still thrown 
 ashore in considerable quantity among the rocks to the 
 south of St. Andrew's. In this St. Andrew's deposit, too, 
 I found the most modern nodules I have yet seen in Scot- 
 land, for they had evidently been hardened into stone dur- 
 ing the recent period; but, though I laid them open by 
 scores, I failed to detect in them anything organic. Sim- 
 ilar nodules of the Drift period, not unfrequent in Canada 
 and the United States, are remarkable for occasionally 
 containing the only ichthyolite found by Agassiz among 
 seventeen hundred species, which still continues to live, 
 and that can be exhibited, in consequence, in duplicate 
 specimens, — the one fit for the table in the character of a 
 palatable viand, — the other for the shelves of a geological 
 museum in the character of a curious ichthyolite. It is 
 the 3Iallotus villosus, or Capelan (for such is its market- 
 name), a little fish of the arctic and semi-arctic seas. " The 
 Mallotus is abundant," says Mr. James Wilson, in his ad- 
 mirable " Treatise on Fishes," " in the arctic seas, where 
 it is taken in immense profusion when approaching the 
 coasts to spawn, and is used as the principal bait for cod. 
 A few are cured and brought to this country in barrels, 
 where they are sold, and used as a relish by the curious in 
 wines." 
 
 Let me next call your attention to the importance, in an 
 economic point of view, of the great geologic events which 
 gave to our country its subsoils, more especially the boul- 
 der-clay. This deposit varies in value, according to the 
 nature of the rocks out of which it was formed; but it is, 
 even where least fertile, a better subsoil than the rock 
 
 1 See Note at the end of the Lectures.
 
 LECTURES ON GEOLOGY. 107 
 
 itself would have been ; and in many a district it furnishes 
 our heaviest wheat soils. To the sand and gravel formed 
 out of it, and spread partially over it, we owe a class of 
 soils generally light, but kindly; and the brick clays are 
 not only of considerable value in themselves, but of such 
 excellence as a subsoil, that the land Avhich overlies them 
 in the neighborhood of Edinburgh still lets at from four 
 to five pounds per acre. I susj)ect that, in oi'der to be 
 fully able to estimate the value of a subsoil, one would 
 need to remove to those rocky lands of the south that 
 seem doomed to hopeless barrenness for want of one. It 
 is but a tedious process through which the minute lichen 
 or dwarfish moss, settling on a surface of naked stone, 
 forms, in the course of ages, a soil for plants of greater 
 bulk and a higher order; and had Scotland been left to 
 the exclusive operation of this slow agent, it would be still 
 a rocky desert, with perhaps here and there a strip of allu- 
 vial meadow by the side of a stream, and here and there 
 an insulated patch of mossy soil among the hollows of the 
 crags ; but, though it might possess its few gardens for the 
 spade, it would have no fields for the plough. We owe 
 our arable land to that geologic agent which, grinding 
 down, as in a mill, the upper layers of the surface rocks of 
 the kingdom, and then spreading over the eroded strata 
 their own debris, formed the general basis in which the 
 first vegetation took root, and in the course of years com- 
 posed the vegetable mould, A foundering land under a 
 severe sky, beaten by tempests and lashed by tides, with 
 glaciers half choking up its cheerless valleys, and with 
 countless icebergs brushing its coasts and grating over its 
 shallows, would have seemed a melancholy and hopeless 
 object to human eye, had tliere been human eyes to look 
 upon it at the time ; and yet such seem to have been the
 
 108 LECTURES ON GEOLOGY. 
 
 circumstances in which our country was placed by Him 
 who, to "perform his wonders," 
 
 < " Plants his footsteps in the sea, 
 
 And rides upon the storm," 
 
 in order that at the appointed period it might, according 
 to the poet, be a land 
 
 " Made blithe by plough and harrow." 
 
 From the boulder-clay there is a natural transition to the 
 boulders themselves, from which the deposit derives its 
 name. These remarkable travelled stones seem, from the 
 old traditions connected with some of them, to have awak- 
 ened attention and excited wonder at an early period, long 
 ere Geology was known as a science ; nor are they without 
 their share of picturesqueness in certain situations. You 
 will jDcrhaps remember how frequently, and with what 
 variety of aspect, Bewick, the greatest of wood engravers, 
 used to introduce them into the backgrounds of his vig- 
 nettes. " A rural scene is never perfect," says Shenstone, a 
 poet of no very large calibre, but the greatest of landscape 
 gardeners, " without the addition of some kind of building : 
 I have, however, known," he adds, " a scaur of rock in 
 great measure supplying the deficiency." And the justice 
 of the poet's canon may be often seen exemplified in those 
 more recluse districts of the country Avhich border on the 
 Highlands, and where a huge rock-like boulder, roughened 
 by mosses and lichens, may be seen giving animation and 
 cheerfulness to the wild solitude of a deep forest-glade, or 
 to some bosky inflection of bank Avaving with birch and 
 hazel on the side of some lonely tarn or haunted streamlet. 
 Even on a dark, sterile moor, where the pale lichen springs
 
 LECTURES ON GEOLOGY. 109 
 
 up among the stunted heath, and the hairy club-moss goes 
 creeping among the stones, some vast bouldei-, rising gray 
 amid the waste, gives to the fatigued eye a reposing point, 
 on which it can rest for a time, and then let itself out on 
 the exjianse around. Boulder-stones are still very abun- 
 dant in Scotland, though for the last century they have 
 been gradually disappearing from the more cultivated 
 tracts where there were fences or farm steadings to be 
 built, or where they obstructed the course of the plough. 
 We find them occurring in every conceivable situation : 
 high on hill-sides, where the shepherd crouches beside them 
 for shelter in a shower; deep in the open sea, where they 
 entangle the nets of the fisherman on his fishing banks; on 
 inland moors, Avhere in some remote age they were labori- 
 ously rolled together to form the Druidical circle or Pict's 
 House ; or on the margin of the coast, where they had been 
 piled over one another at a later time, as protecting bul- 
 warks against the waves. They are no longer to be seen in 
 this neighborhood in what we may term the agricultural 
 region ; but they still occur in great numbers arong the 
 coast, within the belt that intervenes between high and low 
 water, and on an upper moorland zone over which the 
 plough has not yet passed. Mr. Charles M'Laren describes, 
 in his admirable little work on " The Geology of Fife and 
 the Lothians," a boulder of mica schist weighing from eight 
 to ten tons, which rests, among many others, on one of the. 
 Pentland Hills, and which derives an interest from the fact 
 that, as shown by the quality of the rock, the nearest point 
 from which it could have come is at least fifty miles away. 
 A well-known greenstone boulder of still larger size may be 
 seen at the line of half-ebb, about half-way between Leith 
 and Portobello, But though about ten feet in height, it is 
 a small stone, compared with others of its class both in this 
 
 10
 
 110 LECTORES ON GEOLOGY. 
 
 country and tlie Continent. The rock^ as it is well termed 
 (for it is a mass of granite weigliing tifteen hundred tons), 
 on which the colossal statue of Peter the Great at St. 
 Petersburg is placed, is a travelled boulder, which was 
 found dissociated from every other stone of its kind in the 
 middle of a morass ; and Sir Roderick Murchison describes, 
 in one of his papers on the Northern Drift, a Scandinavian 
 boulder thirty feet in height by one hundred and forty in 
 circumference. Most, if not all the boulders which we find 
 in this part of the country on the lower zone, have been 
 washed out of the boulder-clay. Wherever we find a 
 group of boulders on the portion of sea-bottom uncovered 
 by the ebb, we have but to look at the line where the surf 
 breaks when the sea is at full, and there we find the clay 
 itself, with its half-uncovered boulders projecting from its 
 yielding sides, apparently as freshly grooved and scratched 
 as if the transporting iceberg had been at work upon them 
 but yesteixlay. 
 
 I must again adduce the evidence of Sir Charles Lyell, 
 to sliow that masses of this character are frequently ice- 
 borne. " In the river St. Lawrence," we find him stating in 
 his " Elements," " the loose ice accumulates on the shoals 
 during the winter, at which season the water is low. The 
 separate fragments of ice are readily frozen together in a 
 climate where the temperature is sometimes thirty degrees 
 below zero, and boulders become entangled with them ; so 
 that in spring, when the river rises on the melting of the 
 snow, the ice is floated off, frequently conveying the bould- 
 ers to great distances. A single block of granite fifteen 
 feet long by ten feet both in breadth and height, and which 
 could not contain less than fifteen hundred cubic feet of 
 stone, was in this way moved down the river several hun- 
 dred yards, during the late survey in 1837. Heavy anchors
 
 LECTURES ON GEOLOGY. Ill 
 
 of ships lying on the shore have in like manner been closed 
 in and removed. In October 1808 wooden stakes were 
 driven several feet into the ground at one part of the banks 
 of the St. Lawrence at high-water mark, and over them 
 were piled many boulders as large as the united force of six 
 men could roll. The year after, all the boulders had dis- 
 appeai'ed, and others had arri^^ed, and the stakes had been 
 drawn out and carried away by the ice." 
 
 Our Scottish boulders — though in many instances im- 
 mediately associated, as in this neighborhood, with the 
 boulder-clay, and in many others, as in our moorland dis- 
 tricts, with the bare rock — occur in some cases associated 
 with the superficial sands and gravels, and rest upon or 
 over these. And in these last instances they must have 
 been the subjects of a course of ice-borne voyagings subse- 
 quent to the earlier course, and when the laud was rising. 
 Even during the last sixty years, though our winters are 
 now far from severe, there have been instances in Scotland 
 of the transport of huge stones by the agency of ice ; and 
 to two of these, as of a character suited to throw some 
 light on the boulder voyagings of the remote past, I must 
 be permitted to refer. 
 
 Some of my audience may have heard of a boulder well 
 known on both sides of the Moray Frith as the " Travelled 
 Stone of Petty," — a district which includes the Moor of 
 Culloden, and at whose parish church Hector Boece saw 
 the gigantic bones of the colossal Little John. The Clach 
 clhu n-Aban, or black stone of the white bog, — for such is 
 the graphically descriptive Gaelic name of the moss, — 
 measures about six feet in height by from six to seven feet 
 in breadth and thickness, and served, up to the 19th of 
 February 1799, as a march-stone between the properties of 
 Castle Stuart and Culloden. It lay just within flood-
 
 112 LECTURES ON GEOLOGY. 
 
 mark, near where a little stream empties itself into a shallow 
 sandy bay. There had been a severe, long-continued frost 
 throughout the early part of the month ; and the upper 
 portions of the bay had acquired, mainly through the 
 agency of the streamlet, a continuous covering of ice, that 
 had attained, round the base of the stone, Avhich it clasped 
 fast, a thickness of eighteen inches. On the night of tlie 
 19th the tide rose unusually high on the beach, and there 
 broke out a violent hurricane from the east-south-east, ac- 
 companied by a snow-storm. There is a meal mill in the 
 immediate neighborhood of the stone ; and when the old 
 miller — as he related the story to the late Sir Thomas Dick 
 Lauder — got up on the morning of the 20th, so violent 
 was the storm, and so huge the snow-wi'eaths that blocked 
 up every window and door, and rose over the eaves, that he 
 could hardly make his way to his barns, — a journey of but 
 a few yards ; and in returning again from them to his dwell- 
 ing, he narrowly escaped losing liimself in the drift. In 
 looking towards the bay, in one of the pauses of the storm, 
 he could scarce credit his eyesight : the immense Clach du 
 n-Ahan had disappeared, — vanished, — gone clean off the 
 ground ; and he called to his wife in astonishment and 
 alarm, that the "meikle stane was awa." The honest 
 woman looked out, and then rubbed her eyes, as if to verify 
 their evidence ; but the fact was unquestionable, — the 
 "meikle stane" certainly "was awa;" and there remained 
 but a hollow pit in the sand, with a long, shallow furrow, 
 stretching from the pit outwards to where the snow rhime 
 closed thick over the sea, to mark whei-e it had been. 
 When, however, the weather cleared up, the stone again 
 became visible, lying out in the sands uncovered by the ebb, 
 seven hundred and eighty feet from its former position. In 
 the evening of the day, the neighbors flocked out by
 
 LECTURES ON GEOLOGY. 113 
 
 scores to examine the scene of so extraordinary a prodigy- 
 Wliere the stone had lain they found but the deep dent 
 connected by the furrow which lay athwart the bay in the 
 line of the hurricane, with the stone itself, around the base 
 of which there still projected a thick cornice of ice. In its 
 new position the stone still lies; and only a few years ago 
 — mayhap, still — a wooden post which marked the point 
 where the two contiguous properties met, marked also the 
 spot from which, after a rest of ages, it had set out on its 
 short voyage. 
 
 My other case of boulder travelling — in some respects 
 a more curious case than the one related — occurred early 
 in the present century on the eastern coast of Sutherland- 
 shire. Xear the small hamlet of Torribal, in the upper part 
 of Loch Fleet, there stood, about fifty years ago, a rude 
 obelisk of undressed stone, generally regarded as Danish, 
 which, though more ancient than authentic history, or even 
 tradition, in the district, was less so than the old coast line, 
 as it had been evidently erected, subsequent to the last 
 change of level, on the flat marginal stiip which intervenes 
 between the old line and the sea. It rose in the middle of 
 a swampy hollow, which protracted rains sometimes con- 
 verted into a strip of water, and which was sometimes 
 swept by the overflowings of the neighboring river. On 
 the eve of the incident which proved the terminating one 
 in its history, the hollow, previously filled with rain-water, 
 had been fi-ozen to the bottom by a continued frost, which 
 was, however, on the eve of breaking up ; and a dense fog 
 lay thick in the valley, when a benighted Highlander, re- 
 turning tipsy from a market by the light of the moon, came 
 staggering in the direction of the standing stone, and in a 
 drunken frolic set his bonnet on the top of it ; and then 
 wandering oflT into the mist, he lost sight of both stone and 
 
 10*
 
 114 LECTURES ON GEOLOGY. 
 
 bonnet, and, failing to regain them, he had to return bare^ 
 headed to his home. The thaw came on ; the river rose 
 over its banks ; the ice-cal<e around the obelisk floated high 
 above the level, wrenching up the obelisk along with it, as 
 the ice of the St. Lawrence wrenched up the stakes de- 
 scribed by Sir Charles Lyell ; and both ice-cake and obelisk 
 floated down the loch to the sea. As the morning broke — a 
 fierce morning of flood and tempest — they were seen pass^ 
 ing what some forty years ago was known as the Little 
 Ferry ; and the alarm went abroad along the shores on botli 
 sides, that there was a man standing in the middle of the 
 Loch on the floating ice, and in course of being swept out 
 to the ocean. Poor man ! he had been crossing the river, 
 it was inferred, when the ice broke up ; and though the en- 
 terprise was a somewhat perilous one, for the ice fragments 
 were rushing furiously along on the wild tides of the loch, 
 maddened by the inundation, a boat, double manned, shot 
 out from the shore to the rescue, and soon neared the drift- 
 ing ice-floe. It was ultimately seen, however, that the 
 supposed man was but a Danish obelisk, bearing on its head 
 a mysterious bonnet; and bonnet and obelisk were left to 
 find their way to the German Ocean, in which it is proba- 
 ble they now both lie. These modern instances of boulder 
 travelling may serve to show how huge stones originally 
 associated with the boulder-clay may have come to rest 
 on the arenaceous or gravelly deposits which overlie it. 
 Through the second voyage of the Petty boulder, it was 
 deposited on a recently formed bed of sand ; and the stand- 
 ing-stone of Torribal may now rest on sea-shells that were 
 living half a century ago. 
 
 It is held by geologists of high standing, that after the 
 period of submergence represented by the boulder-clays of 
 our country, tlie Bi'itish islands were elevated to such o.
 
 LECTURES ON GEOLOGY. 115 
 
 height over the sea-level, that their distinctive character as 
 islands was lost, and the area which they occupy united to 
 the main land in the character of a western prolongation 
 of the great European continent. It was at this period, 
 says Professor Edward Forbes, that Britain and Ireland 
 received, over the upraised bed of the German Ocean, their 
 Germanic flora, — the last acquired of the five floi'as which 
 compose their vegetation. The evidence on the jjoint, 
 however, still seems somewhat meagre. I can have no 
 doubt that the land stood considerably higher during this 
 Post-Tertiary period than it does now. As shown by the 
 dressed surfaces and rounded forms of many of the smaller 
 islets of the north-western coasts of Scotland, and the 
 markings at the bottom of its lochs and estuaries, and on 
 the rocks along their shores, the latter glaciers must have 
 descended from the central hills of the country fir below 
 the present sea-level ; and we find some of the transverse 
 moraines which they ploughed up before them in their 
 descent existing as gravelly spits, that rise amid the waves, 
 in the middle of long friths or at the entrance of deep bays. 
 I have seen, too, on rocky coasts, considerably below the 
 tide-line at flood, a sort of recent breccia formed by cal- 
 careous springs, which, as the stalagmitical matter could 
 not have been deposited in places exposed to the diurnal 
 washings of the sea, indicated a higher level of the land 
 than now, at the time of its formation ; and the submerged 
 mosses of both Britain and Ireland — mosses now existing 
 in many localities far below the fall of the tide — bear evi- 
 dence, where not more ancient than the boulder-clay, in the 
 same line. But on this obscure passage in the geological 
 history of our country I am unable, from at least actual 
 observation, to say aught more : my few facts lie in the 
 direction of Professor Forbes's theory, but they accompany
 
 116 LECTURES ON GEOLOGY. 
 
 it only a short way. There is a wide gap still unfilled. I 
 may be j^ermitted to remind you, that it is held by the 
 Professor — one of the most accomplished of our geolo- 
 gists — that of the five British floras, we have two in 
 Scotland, — the Germanic flora, and the semi-arctic or 
 Scandinavian flora; that these were introduced into the 
 country at difierent periods ; and that while the Germanic 
 flora dates from the times of the Post-Tertiary elevation 
 of the land, the more ancient of the two — the semi-arctic 
 or Scandinavian — dates from the preceding times of the 
 boulder-clay. Nor does it appear in any degree more im- 
 probable that we should have the descendants of the plants 
 of even the remoter period still vital on our hill-tops, than 
 that we should have the descendants of some of its animals 
 still living in our seas. It seems at first a curious problem, 
 difficult of solution, that widely sejiarated mountain sum- 
 mits should possess the same aljaine plants, — that the sum- 
 mits of Ben Wyvis and Ben Lomond, for instance, or of 
 Ben Nevis and Ben Muich Dhui, should have their species 
 in common, while not a trace of them appears on the lower 
 elevations between. But it simplifies the case to conceive 
 of these alpine plants as the vegetable aborigines of the 
 country, compelled by climatal invasion to shelter in its 
 last bleak retreats, where the winter snows linger unwasted 
 till midsummer, and the breeze is always laden with the 
 chills of the old glacial period. They compose the Celtic 
 portion of the Scottish flora, cooped up in their mountain 
 recesses by the encroachments of those Germanic races 
 of the plant family that flourish, in the altered atmos- 
 phere, or the more genial plains of the country, or on the 
 sunny slopes of its lower hills. That language of flowers 
 in which the ladies of Mohammedan countries have learned 
 to converse is not unappropriately employed in giving
 
 LECTURES ON GEOLOGY. 117 
 
 expression to the various modes of a passion scarce less 
 evanescent than the flowers themselves. But is it not 
 passing strange, tliat we of Scotland should be called on 
 to recognize in the transitory flowers of our sheltered 
 low-lying plains and valleys, and of our high, bleak moors 
 and exposed mountain summits, the records of an antiq- 
 uity so remote, that the stories told by the half-effaced 
 hieroglyphics of Nineveh and of Egypt are of yesterday in 
 comparison ? 
 
 Here the exhibition of our facts illustrative of the Pleis- 
 tocene and Post-Tertiary periods in Scotland properly 
 ends. The existing evidence has been taken, though, of 
 course, briefly and imperfectly, the extent and multiplicity 
 of the subject considered ; and, the record closed, a formal 
 summary of the conclusions founded upon it should now 
 terminate our history. Permit me, however, to present 
 you, in conclusion, not with the formal summary, but a 
 somewhat extended picture, of the whole, exhibited, pan- 
 orama-like, as a series of scenes. The fine passage in the 
 Autumn of Thomson, in which the poet lays all Scotland 
 at once upon the canvas, and surveys it at a glance, must 
 be familiar to you all : 
 
 " Here awhile the Muse, 
 High hovering o'er the broad cerulean scene. 
 Sees Caledonia in romantic view; 
 Her airy mountains, from the waving main. 
 Invested with a keen diffusive sky, 
 Breathing the soul acute ; her forests huge, 
 Incult, robust, and tall, by Nature's hand 
 Planted of old ; her azure lakes between. 
 Poured out extensive, and of watery wealth 
 Full; winding deep and green, her fertile vales. 
 With many a cool, translucent, brimming flood 
 Wash'd lovely, from the Tweed (pure parent stream. 
 Whose pastoral banks first heard my Doric reed.
 
 il8 LECTURES ON GEOLOGY. 
 
 With, sylvan Jed, thy tributary brook). 
 
 To -where the North's inflated tempest foams 
 
 O'er Orcas or Betubium's highest peak." 
 
 Let us in like manner attempt calling up the features of 
 our country in one continuous landscape, as they appeared 
 at the commencement of the glacial period, just as the 
 paroxysm of depression had come on, and bold headland 
 and steep iron-bound islet had begun slowly to settle into 
 the sea. 
 
 The general outline is that of Scotland, though harsher 
 and more rugged than now, for it lacks the softening in- 
 tegument of the subsoils. Yonder are the Grampians, and 
 yonder the Cheviots, and, deeply indenting the shores, yon- 
 der are the well-known estuaries and bays, — the friths of 
 Forth, Tay, and Moray, and the long withdrawing lakes, 
 Loch Katrine, and Loch Awe, and Loch Maree, and the 
 far-gleaming waters of the deep Caledonian Valley, the 
 Ness, and the Oich, and the Lochy. But though the sum- 
 mer sun looks down upon the scene, the snow-line de- 
 scends beneath the top of even our second-class mountains ; 
 and the tall, beetling Ben Nevis, and graceful Ben Lomond, 
 and the broad-based Ben Muich Dhui, glitter in the sun- 
 shine, in their coats of dazzling white, from their summits 
 half-way down to their bases. There are extended forests 
 of the native fir on the lower plains, mingled with the slim- 
 mer forms and more richly-tinted foliage of the spruce 
 pine. On the upper grounds, thickets of stunted willows 
 and straggling belts of diminutive birches skirt the ravines 
 and water-courses, and yellow mosses and gi'ay lichens 
 form the staple covering of the humbler hill-sides and the 
 moors. But the distinctive feature of the country is its 
 glaciers. Fed by the perpetual snows of the upper heights, 
 the deeper valleys among the mountains have their rigid
 
 LECTURES ON GEOLOGY. 119 
 
 ice-rivers, that in the narrower friths and lochs of the 
 "western and northern coasts shoot far out, mole-like, into 
 the tide. And, lo I along the shores, in sounds and bays 
 never yet ploughed by the keel of voyager, vast groups 
 of icebergs, that gleam white to the sun, like the sails of 
 distant fleets, lie moveless in the calm, or drift slowly along 
 in rippling tideways. Nor is the land without its inhabi- 
 tants, though man has not yet appeared. The colossal 
 elephant, not naked and dingy of coat, like his congener of 
 the tropics, but shaggy, with long red hair, browses among 
 the woods. There is a strong-limbed rhinoceros wallow- 
 ing in yonder swamp, and a herd of reindeer cropping the 
 moss high on the hill-side beyond. The morse is basking 
 on that half-tide skerry ; and a wolf, swept seawards by 
 the current, howls loud in teiTor from yonder drifting ice- 
 floe. We have looked abroad on our future country in the 
 period of the first local glaciers, ere the submergence of 
 the land. 
 
 Ages pass, and usher in the succeeding period of the 
 "boulder-clay. The prospect, no longer that of a continu- 
 ous land, presents us with a wintry archipelago of islands, 
 broken into threje groups by two deep ocean-sounds, — 
 the ocean-sound of the great Caledonian Valley, and that 
 of the broader but shallower valley which stretches across 
 the island from the Clyde to the Forth. We stand full in 
 front of one of these vast ocean-rivers, — the southern one. 
 There are snow-enwrapped islets on either side. Can yon- 
 der thickly-set cluster be the half-submerged Pentlands? 
 and yonder pair of islets, connected by a low, flat neck, the 
 eastern and western Lomonds ? and yonder half-tide rock, 
 blackened with algze, and around which a shoal of ijorj^oises 
 are gamboling, the summit of Arthur Seat ? The wide 
 sound, now a rich agricultural valley, is here studded by
 
 120 LECTURES ON GEOLOGY. 
 
 its fleets of tall icebergs, — there cumbered by its level 
 fields of drift ice. Nature sports ■ wantonly amid every 
 variety of form ; and the motion of the great floating 
 masses, cast into shapes Avith which we associate moveless 
 solidity, adds to the magical efiect of the scene. Here a 
 flat-roofed teraj^le, surrounded by colonnades of hoar and 
 wasted columns, comes drifting past ; there a cathedral, 
 furnished with towers and spire, strikes heavily against the 
 rocky bottom, many fathoms beneath, and its nodding pin- 
 nacles stoop at every blow. Yonder, already fast agi'ound, 
 there rests a ponderous castle, with its curtained towers, 
 its arched gateway, and its multitudinous turrets, reflected 
 on the calm surface beneath ; and pyramids and obelisks, 
 buttressed ramparts, and embrazured watch-towers, with 
 shapes still more fantastic, — those of ships, and trees, and 
 brute and human forms, — crowd the retiring vista beyond. 
 There is a scarce less marked variety of color. The in- 
 tense white of the field-ice, thinly covered with snow, and 
 glittering without shade in the declining sun, dazzles the 
 eye. The taller icebergs gleam in hues of more softened 
 radiance, — here of an emerald green, there of a sapphire 
 blue, yonder of a paly marble gray ; the light, polarized 
 by a thousand cross reflections, sports amid the planes and 
 facets, the fissures and pinnacles, in all the rainbow gor- 
 geousness of the prismatic hues. And bright over all rise 
 on the distant horizon the detached mountain-tops, now 
 catching a flush of crimson and gold from the setting lumi- 
 nai-y. But the sun sinks, and the clouds gather, and the 
 night comes on black with tempest ; and the grounded 
 masses, moved by the violence of the aroused winds, grate 
 heavily along the bottom ; and while the whole heavens 
 are foul with sleet and snow-rack, and the driving masses 
 clash in rude collision, till all beneath is one wide stun-
 
 LECTURES ON GEOLOGY. 121 
 
 ning roar, the tortured sea boils and dashes around them, 
 turbid with the comminuted debris of the fretted rocks 
 below. 
 
 The vision belongs to an early age of the boulder-clay: 
 it changes to a. later time; and the same sea spreads out 
 as before, laden by what seem the same drifting ice-floes. 
 But the lower hills, buried in the profound depths of ocean, 
 are no longer visible; the Lammermuirs have disappeared; 
 and the slopes of Braid and Duddingstone, with 
 
 " North Berwick Law, with cone of green. 
 And Bass amid the waters; " 
 
 and we can determine their place by but the huger ice- 
 bergs that lie stranded and motionless on their peaks ; 
 while the lesser masses drift on to the east. Moons wax 
 and wane, and tides rise and fall ; and still the deep cur- 
 rent of the gulf stream flows ever from the west, traversing 
 the wide Atlantic, like some vast river winding through 
 an enormous extent of meadow ; and, in eddying over the 
 submerged land, it arranges behind the buried eminences, 
 in. its own easterly line, many a long trail of gravel and 
 debris, to form the Crag and Tail phenomenon of future ge- 
 ologists. As we extend our view, we may mark, far in the 
 west, where the arctic current, dotted white with its ice- 
 mountains and floes, impinges on the gulf stream ; and 
 where, sinking from its chill density to a lower stratum 
 of sea, it gives up its burden to the lighter and more tepid 
 tide. A thick fog hangs over the junction, where the 
 warmer waters of the west and south encounter the chill, 
 icy air of the north ; and, steaming forth into the bleak at- 
 mosphere like a seething cauldron, the cloud, when the west 
 wind blows, fills with its thick gray reek the recesses of 
 the half-foundered land, and obscures the prospect. 
 
 ]1
 
 122 LECTURES ON GEOLOGY. 
 
 Anon there is another change in the dream. The long 
 period of submergence is past; the country is again rising; 
 and, under a climate still ungenial and severe, the glaciers 
 lengthen out seawards, as the land broadens and extends, 
 till the northern and western Highlands seem manacled in 
 ice. Even the lower hill-tops exhibit an alpine vegetation, 
 beautiful, though somewhat meagre; while in the friths 
 and bays, the remote ancestors of many of our existing 
 shells that thrive in the higher latitudes, still mix, as at an 
 earlier period, Avith shells whose living representatives are 
 now to be sought on the coasts of northern Scandinavia 
 and Greenland. Ages pass ; the land rises slowly over the 
 deep, terrace above terrace ; the thermal line moves grad- 
 ually to the north ; the line of perpetual snow ascends be- 
 yond the mountain summits; the temperature increases; the 
 ice disappears; the semi-arctic plants creep up the hill-sides, 
 to be supplanted on the plains by the leafy denizens of 
 happier climates ; and at length, under skies such as now 
 look down ujDon us, and on nearly the existing breadth of 
 land, the human jjeriod begins. The half-naked hunter, 
 armed with his hatchet or lance of stone, pursues tlie roe 
 or the wild ox througli woods that, though comparatively 
 but of yesterday, already present appearances of a hoar 
 antiquity ; or, when the winter snows gather around his 
 dwelling, does battle at its beleaguered threshold with the 
 hungry wolf or the bear. The last great geologic change 
 takes place : the coast line is suddenly elevated ; and the 
 country presents a new front to the sea. And on the 
 widened platform, when yet other ages have come and 
 gone, the historic period commences, and the light of a 
 classical literature falls for the first time on the incidents 
 of Scottish story, and on the bold features of Scottish 
 character.
 
 LECTURES ON GEOLOGY. 123 
 
 It is said that modern science is adverse to the exercise 
 and development of the imaginative faculty. But is it 
 really so ? Are visions such as those in which we have 
 been indulging less richly charged with that poetic pabu- 
 lum on which fancy feeds and grows strong, than those 
 ancient tales of enchantment and faery which beguiled of 
 old, in solitary homesteads, the long winter nights? Be- 
 cause science flourishes, must poesy decline ? The com- 
 plaint serves but to betray the weakness of the class who 
 urge it. True, in an age like the present, — considerably 
 more scientific then poetical, — science substitutes for the 
 smaller poetry of fiction, the great poetry of truth ; and 
 as there is a more general interest felt in new revelations 
 of what God has wrought, than in exhibitions of what the 
 humbler order of poets have half borrowed, half invented, 
 the disappointed dreamers complain that the "material 
 laws " of science have pushed them from their place. As 
 well might the Arab who prided himself upon the beauty 
 of some white tent which he had reared in some green 
 oasis of the desert, corajilain of the dull tools of Belzoni's 
 laborers, when engaged in clearing from the sands the 
 front of some august temple of the ancient time. It is 
 not the tools, it might be well said to the complainer, that 
 are competing with your neat little tent ; it is the sublime 
 edifice, hitherto covered up, which the tools are laying 
 bare. Nor is it the material laws, we may, on the same 
 principle, say to the poets of the querulous cast, that are 
 overbearing your little inventions, and making them seem 
 small ; but those sublime works and wonderful actings of 
 the Creator which they unveil, and bring into comparison 
 with yours. But from His works and His actings have the 
 masters of the lyre ever derived their choicest materials ; 
 and whenever a truly great poet arises, — one that will
 
 124 LECTURES ON GEOLOGY. 
 
 add a profound intellect to a powerful imagination, — he 
 will find science not his enemy, but an obsequious caterer 
 and a devoted friend. He will find sermons in stones, and 
 more of the suggestive and the sublime in a few broken 
 scaurs of clay, a few fragmentary shells, and a few green 
 reaches of the old coast line, than versifiers of the ordinary 
 calibre in their once fresh gems and flowers, — in sublime 
 ocean, the broad earth, or the blue firmament and all its 
 stars.
 
 LECTURE THIRD. 
 
 The Poet Delta (Dr. Moir) — His Definition of Poetry — His Death — His Burial- 
 place at Inveresk — Vision, Geological and Historical, of the Surrounding 
 Country — "What is it that imparts to Nature its Poetry — The Tertiary Forma- 
 tion in Scotland — In Geologic History all Ages contemporary — Amber the 
 Besin of the Pinus succinifer — A Vegetable Production of the Middle Tertiary 
 Ages — Its Properties and Uses — The Masses of Insects inclosed in it — The 
 Structural Geology of Scotland — Its Trap. Rock — The Scenery usually asso- 
 ciated with the Trap Rock — How formed — The Cretaceous Period in Scotland 
 — Its Productions — The Chalk Deposits — Death of Species dependent on Laws 
 different from those which determine the Death of Individuals — The Two 
 great Infinites. 
 
 The members of the Philosophical Institution of Edin- 
 burgh enjoyed the privilege last season of listening to one 
 of the sweetest and tenderest of modern British poets 
 eloquently descanting on the history of modern British 
 poetry. Rarely had master established for himself a bet- 
 ter claim to teach. And, regarding the elegant volume 
 produced on that occasion, so exquisite in its taste and so 
 generous in its criticisms, it may justly be said that perhaps 
 its only, at all events its gravest defect, is the inevitable 
 one that, in exhibiting all that during the bypast genera- 
 tion was most characteristic and best in the poesy of our 
 country, it should have taken no cognizance of the poetry 
 of Delta. Dr. Moir had just finished his course, but his 
 volume had not yet appeared, when, ufged by a friend, I 
 perhaps too rashly consented to contribute two lectures to 
 a course then delivering in the native town of the poet ; 
 and in one of these I expressed the conviction to which I 
 
 11*
 
 126 LECTURES ON GEOLOGY. 
 
 gave utterance last season in this place, that there is no 
 incompatibility between the pursuit of geologic science 
 and a genial development of the poetic faculty. Dr. Moir 
 had honored my address with his presence ; he had listened 
 with apparent attention to a view very much opjiosed, as 
 I was told after the breaking up of the meeting, to one 
 which he himself had promulgated to the Institution only 
 a few weeks before; and on the publication of his little 
 volume, he politely sent me a copy, accompanied by a kind 
 note, in which he referred to the point apparently at issue 
 between us as involving rather a seeming than a real dif- 
 ference. " Our antagonism respecting the relations of 
 poetry and science," he said, "is, I doubt not, much more 
 apparent than real, and arises simply from the opposite 
 aspects in which we have regarded the subject." I read 
 his work Avith interest ; and at first deemed the differ- 
 ence somewhat more than merely apparent. I found 
 the lecturer speaking of " staggering blows " inflicted on 
 the poetry of the age by science in not a few formidably 
 prosaic shapes, — in the shape, among the rest, of "geolog- 
 ical exposition ; " and of " rocks stratified by the geologists 
 as satins are measured by mercers," and, in consequence, 
 no longer redolent of that emotion of the sublime which 
 was wont to breathe forth of old from broken crags and 
 giddy precipices. But his definition of poetry reassured 
 me, and set all right again, "Poetry," he said, "may be 
 defined to be objects or subjects seen through the mirror 
 of imagination, and descanted on in harmonious language; 
 and if so, it must be admitted that the very exactness of 
 knowledge is a barrier to the laying on of that coloring by 
 which facts can be invested with the illusive hues of poetry. 
 Wherever light penetrates the obscure and illuminates the 
 uncertain, we may rest assured that a demesne has been
 
 LECTURES ON GEOLOGY. 127 
 
 lost to the realms of imagination." Now, if such be poe- 
 try, I said, and such the conditions favorable to its devel- 
 opment, the poets need be in no degree jealous of the 
 geologists. The stony science, with buried creations for 
 its domains, and half an eternity charged with its annals, 
 possesses its realms of dim and shadowy fields, in which 
 troops of fancies already walk like disembodied ghosts in 
 the old fields of Elysium, and which bid fair to be quite 
 dark and uncertain enough for all the pur2)oses of poesy 
 for centuries to come. 
 
 Alas ! only a few weeks after, amid hundreds of his sor- 
 rowing friends and townsmen, I followed the honored re- 
 mains of the poet to the grave; and heard, in that old, 
 picturesque burying-ground which commands on its green 
 ridge the effluence of the Esk, the shovelled earth falling 
 heavy on the coffin-lid. It was a lovely day of chequered 
 shadow and sunshine ; and tlie wide frith slept silently in 
 the calm, with a dream-like spectrum of the heavens mir- 
 rored on its bosom. From the sadness of the present my 
 thoughts let themselves out upon the past. I stood among 
 the groves on a grassy mound which had been reared by 
 the old Roman invader greatly more than a thousand years 
 before ; and I bethought me how, on visiting the place a 
 few twelvemonths previous, for the first time, I had first 
 of all sought out the burying-ground of the family of the 
 deceased, — a spot endeared to every lover of poesy by 
 those tenderest and sweetest of " domestic verses " which 
 show how truly, according to Cowper, " the poet's lyre " 
 had been " the poet's heart ; " and how I had next set my- 
 self to trace, as next in interest, the remains of that stem 
 old people whose thirst of conquest and dominion had 
 led them so far. And lo ! like a dream remembered in a 
 dream, as the crowd broke up and retired, the visions of
 
 128 LECTURES OX GEOLOGY. 
 
 that quiet day were again conjured up before me, but bear- 
 ing now a felt reference to the respected dead, and accom- 
 panied by the conviction that, had we been destined to 
 meet, and to compare at length our respective views, we 
 should have found them essentially the same. 
 
 On that rising ground, so rich in historic associations, 
 both Somerset and Cromwell had planted their cannon, 
 and it had witnessed the disaster at Pinkie, and the head- 
 long flight of the dragoons of Cope. But, passing over 
 the more recent scenes, the vision of a forest-covered coun- 
 try rose before me, — a vision of the ancient aboriginal 
 woods rising dusky and brown in one vast thicket, from 
 the windings of the Esk to the pale brow of the Pent- 
 lands. Nor was the landscape without its human figures. 
 The grim legionaries of the Proconsul of Augustus were 
 opening with busy axes a shady roadway through the 
 midst; and the incessant strokes of the axe and the crash 
 of falling trees echoed in the silence throughout the valley. 
 And then there arose another and earlier vision, when the 
 range of semicircular heights which rise above the ancient 
 Saxon borough, with its squat tower and antique bridge, 
 existed as the coast line, and the site of the town itself as 
 a sandy bay, swum over by the sea-wolf and the seal ; and 
 the long ridge now occupied by garden and villa, chiirch 
 and burying-ground, as a steep, gravelly bar, heaped up in 
 the vexed line, where the tides of the river on the one 
 hand contended with the waves of the Frith on the other; 
 and the Esk, fed by the glaciers of the interior, whose blue 
 gleam I could mark on the distant Lammermoors and the 
 steeper Pentlands, rolled downwards, a vast stream, that 
 filled from side to side the ample banks which, even when 
 heaviest in flood, it scarce half fills now ; while a scantier 
 and dingier foliage than before, composed chiefly of taper
 
 LECXmiES ON GEOLOGY. 129 
 
 spruce and dark pine, roughened the lower plains, and 
 flung its multitudinous boughs athwart the turbid and 
 troubled eddies. And then there arose yet other and 
 remoter scenes. From a foreground of weltering sea I 
 could mark a scattered archipelago of waste, uninhabited 
 islands, picturesquely roughened by wood and rock ; and 
 near where the Scottish capital now stands, a submarine 
 volcano sent forth its slim column of mingled smoke and 
 vapor into the sky. And then there rose in quick succes- 
 sion scenes of the old Carboniferous forests : long Avith- 
 drawing lakes, fringed with dense thickets of the green 
 Calamite, tall and straight as the masts of pinnaces, and 
 inhabited by enormous fishes, that glittered through the 
 transparent depths in their enameHed armor of proof; or 
 glades of thickest verdure, where the tree-fern mingled 
 its branch-like fronds with the hirsute arms of the gigan- 
 tic club-moss, and where, amid strange forms of shrub and 
 tree no longer known on eai'th, the stately Araucarian 
 reared its proud head two hundred feet over the soil ; or 
 yet again, there rose a scene of coral bowers and encrinal 
 thickets, that glimmered amid the deep green of the an- 
 cient ocean, and in which, as in the groves sung by Ovid, 
 the plants were sentient, and the shrinking flowers bled 
 when injured. And, last of all, on the further limits of 
 organic life a thick fog came down upon the sea, and my 
 excursions into the remote past terminated, like the voy- 
 age of an old fabulous navigator, in thick darkness. Each 
 of the sei'ies of visions, whether of the comparatively re- 
 cent or the remote past, in which I at that time indulged, 
 had employed the same faculties and gratified the same 
 feelings ; and though, in surveying the stuflf out of which 
 they had been sublimed, I could easily say where the his- 
 toric ended and the geologic began, no corresponding line
 
 130 LECTURES ON GEOLOGY. 
 
 indicated in the visions themselves where the poetry ended 
 and the prose began. The visions, whether historic or 
 geologic, " were of imagination all compact." They all 
 involved the same processes of mind — though, of course, 
 in this instance mind of a humbler order and ruder tex- 
 ture — as those exhibited in the sweet and fragrant verse 
 of the poet himself, — as those exercised, let me say, in his 
 vision on " Mary's Mount," when, with "quiet graves above, 
 and surrounded by quiet fields, he saw the contending 
 hosts of a former day thronging the lower ground, and, 
 
 " With h\lt to hilt, and hand to hand, 
 The children of our mother land 
 To battle came; " 
 
 or when he called up, after the lapse of half a lifetime, 
 how when, in a wintry morning, he had journeyed before 
 daybreak, a happy boy, along the frozen Esk, and saw 
 
 " In the far west the Pentland's gloomy ridge 
 Belting the pale blue sky, whereon a cloud, 
 Fantastic, gray, and tinged with solemn light, 
 Lay like a dreaming monster, and the moon. 
 Waning, above its silvery rim upheld 
 Her horns, as 't were a spectre of the past." 
 
 I shall continue to hold, therefore, that there was no real 
 difference between the views of the poet and those which 
 I myself entertain, but that, as he himself well expressed 
 it, our " apparent antagonism arose simply from the oppo- 
 site aspects in Avhich we had viewed the subject." He had 
 been thinking of but stiff diagrams and hard names, — of 
 dead strata measured off, in "geological exposition," by 
 the yard and the mile, and enveloped in the obscuring 
 folds of a Babylonish phraseology; while I, looking through 
 the crooked characters and uncouth sounds in which the
 
 LECTURES ON GEOLOGY. 131 
 
 meanings of the science are locked up, to the meanings 
 themselves, was luxuriating among the strange, wild nan'a- 
 tives and richly poetic descriptions of which its pregnant 
 records consist. 
 
 What is it, let me ask, that imparts to Nature its poe- 
 try? It is not in Nature itself; it resides not either in 
 dead or organized matter, — in rock, or bird, or flower ; 
 " the deep saith it is not in me, and the .sea saith it is not 
 in me." It is in mind that it lives and breathes : external 
 nature is but its storehouse of subjects and models ; and it 
 is not until these are called up as images, and invested with 
 " the light that never was on land or sea," that they cease 
 to be of the earth earthy, and form the ethereal stuff of 
 which the visions of the poet are made. Nay, is it not 
 mainly through that associative faculty to which the sights 
 and sounds of present nature become suggestive of the 
 images of a nature not present, but seen within the mind, 
 that the landscape jjleases, or that we find beauty in its 
 woods or beside its streams, or the impressive and the sub- 
 lime among its mountains and rocks? Nature is a vast tab- 
 let, inscribed with signs, each of which has its own signifi- 
 cancy, and becomes poetry in the mind when read ; and 
 geology is simply the key by which myriads of these signs, 
 hitherto undecipherable, can be unlocked and perused, and 
 thus a new province added to the poetical domain. We 
 are told by travellers, that the rocks of the wilderness of 
 Sinai are lettered over with strange characters, inscribed 
 during the forty years' wanderings of Israel. They testify, 
 in their very existence, of a remote past, when the cloud- 
 o'ershadowed tabernacle rose amid the tents of the desert; 
 and who shall dare say whether to the scholar who could 
 dive into their hidden meanings they might not be found 
 charged with the very songs sung of old by Moses and by
 
 132 LECTURES ON GEOLOGY. 
 
 Miiiam, when the sea rolled over the pride of Egypt ? To 
 the geologist every rock bears its inscri2:)tion engraved in 
 ancient hieroglyphic charactei's, that tell of the Creator's 
 journeyings of old, of the laws which He gave, the tab- 
 ernacles which He reared, and the marvels which He 
 wrought, — of mute prophecies wrapped up in type and 
 symbol, — of earth gulfs that opened, and of reptiles that 
 flew, — of fiery plagues that devastated on the dry land, 
 and of hosts more numerous than that of Pharaoh, that 
 " sank like lead in the mighty watei's ; " and, having in 
 some degree mastered the occult meanings of these strange 
 hieroglyphics, we must be permitted to refer, in asserting 
 the poetry of our science, to the sublime revelations with 
 which they are charged, and the vivid imagery Avhich they 
 conjure up. But our history lags in its progress, while 
 we discuss the poetic cai^abilities of the study through 
 which its records are read and its materials derived. 
 
 In the deposits of that Tertiary division of the geologic 
 formation which represents in the history of the globe the 
 period during which mammals began to be abundant, and 
 in which the great Cuvier won his laurels, Scotland is one 
 of the poorest of European countries. Save for the com- 
 paratively recent discovery of Tertiary beds in the island 
 of Mull by a nobleman fitted by nature either to adorn 
 the literature or extend the science of his country, the 
 geological historian would have to pass direct from the 
 Pleistocene beds, with their grooved and polished pebbles 
 and their semi-arctic shells, to the Chalk fossils of Banff and 
 Aberdeen. But the discovery of his Grace the Duke of 
 Argyll furnislies us with an interesting glimpse of a middle 
 period widely different in its character from either the 
 Cretaceous system or the boulder-clay. In the island of 
 Mull, in a headland that rises about one hundred and thirty
 
 LECTURES ON' GEOLOGY. 133 
 
 feet over the sea, there occur, interposed between thick 
 beds of trap, three comparatively thin beds of a gray are- 
 naceous shale, charged with fossil leaves, as beautifully 
 spread out, and with their ribs and veins as distinctly vis- 
 ible, as if they had been preserved in the herbarium of a 
 botanist. Most of them belong to extinct species of exist- 
 ing families of dicotyledonous trees, such as the plane and 
 the buckthorn, mingled, however, with narrow linear leaves 
 of cone-bearing trees, which are supposed to belong, in 
 this instance, to a species of yew, and with what seem the 
 fronds of fern and the stems of equisetacea. Some of the 
 beds of coal which have been long known to occur among 
 the traps of the island of Mull are regarded by the Duke 
 of Argyll as prolongations of these Tei'tiary leaf-beds, so 
 mineralized by some metamorphic action as to haA^e lost 
 the organic structure. There must have been vast accu- 
 mulations of leaves ere they could have yielded beds of 
 coal. The middle or second bed of the three his Grace 
 describes as peculiarly rich in the leafy impressions of this 
 ancient period ; and I need scarce say how suggestive the 
 glimpse is which is furnished us by these buried layers 
 of the foliage of Tertiary forests in Scotland, of which no 
 other known memorial remains. You all remember Cole- 
 ridge's fine comparison of the sorely-worn sails of the 
 vessel in which the ancient mariner perfomied his voyage 
 of peril and prodigy, to 
 
 " Brown skeletons of leaves that lay 
 The forest brook along, 
 When the ivy tod is hea-vT^ with snow. 
 And the owlet whoops to the wolf below; " 
 
 and you must have often marked the extreme delicacy of 
 those deposited leaves, macerated during the winter sea- 
 
 12
 
 134 LECTURES ON GEOLOGY. 
 
 son at the bottom of some woodland pool, which sug- 
 gested the i^oot's simile. In that Tertiary period to which 
 the leaf-beds of Mull belong, it would seem that extensive 
 forests, chiefly of deciduous trees, shed year after year 
 their summer coverings of leaves, some of which fell, and 
 some of which were blown by the autumnal gusts, into the 
 streams of the country, and were swept down by the cur- 
 rent to lakes or estuaries, where they lay gradually resolv- 
 ing into such brown skeletons as caught the eye of Cole- 
 ridge. We learn further, that there were forces active at 
 the time, of which at any later period we have had no 
 examples in the British islands. One of the leaf-beds 
 described by his Grace is overlaid by a bed of volcanic 
 ashes or tuiF seven feet thick; another by a bed of similar 
 ashes mixed with chalk flints, twenty feet thick ; and yet 
 another — the topmost layer — bears over it a bed of over- 
 flowing columnar basalt, forty feet thick. The volcanic 
 agencies were active in what is now Scotland dui'ing the 
 ages of its Tertiary forests. 
 
 The only Tertiary fossils of Scotland yet discovered are 
 these forest and fern leaves of the Mull deposits. Their 
 place in the great geologic division to which they belong 
 is still definitely to fix ; but some of our higher geologists 
 are, I find, disposed to refer them to the second Tertiary 
 or Miocene epoch, though with considerable hesitation. 
 They belong, it is probable, to a period not very widely 
 removed from that of the richly fossiliferous Marlstone of 
 OEningen, on the banks of the Rhine, with its vast abun- 
 dance of plants, chiefly dicotyledonous, — of fishes specifi- 
 cally different from those which now exist, but of the 
 existing genera, — of a fox, which only the comparative 
 anatomist can distinguish from the recent species of this 
 country, — and of reptiles generically akin to those of
 
 LECTURES ON GEOLOGY. 135 
 
 the United States. It is a curious fact that, both in its 
 aniraal and vegetable productions, that part of the New 
 World which borders upon the Atlantic in the temperate 
 zone, from Carolina to the mouth of the St. Lawrence, still 
 presents very much the appearance which was presented 
 by the flora and fiuna of Eui'ope during the later Tertiary 
 periods. It has been often remarked, in reference to 
 human manners and the progress of civilization, that all 
 ages of the world may be regarded as contemporary. 
 Man is still in many of the South Sea Islands what he was 
 in our own country previous to the times of the Roman 
 invasion; and there are provinces in Spain and Portugal 
 in Avhich neither the people nor the clergy have got be- 
 yond the semi-barbarism of the Middle Ages. Curiously 
 enough, in geologic history also, though in a narrower and 
 more restricted sense, all ages are contemporary. The 
 Galapagos have their age of reptiles. New Zealand its 
 age of birds, and New Holland its age of marsupial quad- 
 rupeds. These countries bear now, in not a few par- 
 ticulars, the character of the Oolitic period in our own 
 country. Again, on the eastern coasts of North America 
 we are presented with a vegetation greatly resembling that 
 of some of the later Tertiary periods ; and of several of 
 its animals the type is still more ancient. America, though 
 emphatically the IVe^c World in relation to its discovery 
 by civilized man, is, at least in these regions, an old world 
 in relation to geological type ; and it is the so-called Old 
 World that is in reality the new one. " If we compare," 
 says Professor Agassiz, in his late admirable work, " Lake 
 Superior," — "if we compare a list of the fossil trees and 
 shrubs from the Tertiary beds of CEningen Avith a cata- 
 logue of the trees and shrubs of Europe and North Amer- 
 ica, it will be seen that the differences scarcely go beyond
 
 136 LECTURES ON GEOLOGY. 
 
 those shown by the different floras of these continents 
 under the same latitudes. But what is quite extraordi- 
 nary and unexjjected is the foot, that the European fossil 
 plants of that locality resemble more closely the trees and 
 shrubs which grow at present in the eastern parts of North 
 America, than those of any other part of the world ; thus 
 allowing us to express correctly the difference between the 
 opposite coasts of these continents, by saying that the 
 present eastern American flora, and, I may add, the fauna 
 also, have a more ancient character than those of Europe. 
 The plants, especially the trees and shrubs growing in our 
 days in the United States, are, as it were, old-fashioned ; 
 and the characteristic genera Lagoings, Chelydra, and the 
 large Salamanders, with permanent gills, that remind us 
 of the fossils of CEningen, are at least equally so ; they 
 hear the marks of former agesP This interesting fact — 
 vouched for by assuredly no mean authority — may enable 
 us to conceive of the general aspect of our country, so far 
 at least as its appearance depended on its vegetation, to- 
 wards the close of the Miocene period. Old Scotland ex- 
 hibited features in that age greatly resembling those pre- 
 sented to the puritan fathers by the forest-covered shores 
 of New England little more than two centuries ago. But 
 no family of man dwelt in its solitary woods ; and, as 
 shown by its widely spread deposits of trap-tuff, and its 
 vast beds of overlying basalt, broken by faults and shifts, 
 its ancient volcanoes had not yet died out, and it must 
 have had its frequent earthquake agues and shaking fits. 
 
 There is, however, another witness besides the leaf-beds 
 of the island of Mull, which we may properly call into court 
 to give evidence regarding the Tertiary period in Scotland. 
 It is known that from a very eai*ly time masses of amber 
 have been occasionally furnished by the north-eastern
 
 LECTURES OX GEOLOGY. 137 
 
 shores of the kingdom, in especial by that extensive tract 
 of coast which stretches from the Buchan-ness to the 
 Frith of Tay ; and the geologist now recognizes amber 
 as a vegetable production of the Middle Tertiary ages. 
 It is the resin of an extinct pine, which the fossil botanist 
 has only of late learned to term the Pinus succinifer, or 
 amber pine, but which the Prussian peasantry, who gather 
 amber on the southern shores of the Baltic, used for ages 
 to associate with this substance, from its occurrence in a 
 fossil state in the same beds as atnher xcood. The orna- 
 mental character of this precious resin seems to have been 
 appreciated by the native Scotch at an early period : beads 
 of amber have been found in the old sepulchral barrows 
 of the kingdom. Its value, however, as we learn from the 
 first notice of it which occurs in our written history, — 
 that of Hector Boece, — has not been always appreciated. 
 After describing it, not very inadequately, as " ane maner 
 of gouin or electuar, hewit like gold, and sa attractive of 
 natur, that it drawis stra, flax, or hemmes of claethis to it 
 in the samen maner as does an adamant stone grow," he 
 goes on to say, that " twa year afore the comin af [his] 
 buke to licht (lo2i) thair arrivit an gret lompe of this 
 goum in Buchquhane, als meikle as an hens ; and wes 
 brocht hame by the herdes quhilk wer kepand thair bestis, 
 to thair housis, and cassin in the fere. And becaus they 
 fand an smell and odour thairwith, they scha to thair 
 maister that it wes garand for the twsens that is maid in 
 the kirkes. Thair maister wes ane rud man as thay wer; 
 and tuk hot ane litell pai't thairof, and left the remanent 
 part behind him as mater of litell effect. All the parts of 
 this goum, quhen it wes broken, wes of hew of gold, and 
 schone lyke the licht of an candell. The maist part of 
 this goum or electuar wes destroyit be rud peple afore 't 
 
 12*
 
 138 LECTURES ON GEOLOGY. 
 
 cam to any wise mannis eirs ; of quhome may be verifyet 
 the proverb, ' The sow cares not for balme.' Als sone as I 
 wes aclvertisit thairof, I maid sic diligence that ane pairt 
 of it was brocht me at Aberdene." I may add to this 
 notice of the old chronicler, that uj? to a comparatively 
 recent period, ornaments of amber, especially amber beads 
 of large size, or, as they were termed by our ancestors, 
 "laraour beads," were highly valued by the humbler Scotch. 
 That mysterious attractive proj^erty which resided in this 
 gem-like resin, and which has since been found pregnant 
 with that wonderful science to which the substance has 
 given its Greek name, electrura, threw a halo of mystery 
 around it, that served to enhance its native beauty. The 
 Laird of Dumbiedikes was, it must be confessed, neither a 
 very fervent nor very poetical lover ; but a lover he was ; 
 and yet he could find nothing more apt with which to 
 compare the eyes of his mistress, when turned upon him 
 in her gratitude, than to beads of amber. "Dinna ye 
 think," said the laird, " puir Jeanie's e'en, wi' the tears 
 in them, glanced like lamour beads, Mr. Saddletree ? " 
 
 To the geologist this precious gum of the Tertiary ages 
 is fraught with a peculiar interest, from the circumstance 
 that it forms the best of all matrices for the pi'eservation 
 of organisms of the more fragile kinds. Mosses, fungi, 
 and liverworts, are plants of so delicate a structure, that 
 they are rarely or never preserved in shale or stone ; but 
 specimens of all three have been found locked up in 
 amber in a state of the most perfect keeping. And, 
 besides containing fragments of the pine which produced 
 it, it has been found to contain minute pieces of four other 
 species of pine, with bits of cypresses, ycAvs, junipers, 
 oaks, poplars, beeches, etc., — in all, forty-eight different 
 species of shrubs and trees, which must have flourished in
 
 LECTURES ON GEOLOGY. l89 
 
 the forests where it gi-ew, and which, "viewed in the 
 group, may be regarded as constituting," says Professor 
 Goppert, "a flora of North American character." You 
 will of course i-eraark how directly this evidence bears on 
 that of Professor Agassiz. The most remarkable organ- 
 isms of the amber are, however, its insects, — a kind of 
 fossils suggestive of a very different poetry from that 
 which Pope elaborated from them in his well-known 
 simile : 
 
 "Pretty in amber to observe the forms 
 Of hairs, or straws, or dirt, or grubs, or worms : 
 The things, we Itnow, are neither rich nor rare, 
 But wonder how the mischief they got there! " 
 
 Fossil insects occur in both the Secondary and Palaeozoic 
 divisions, but rarely indeed in a state of sufiicient entire- 
 ness to enable the entomologist to distinguish their spe- 
 cies. Even in classing them into families and genera, our 
 best writers on the subject, such as the Rev. Mr. Brodie, 
 confess that some of the number are very imperfectly 
 made out. In the amber, on the contrary, even the most 
 delicate ephemeitB that ever sported for a single summer 
 evening in a forest glade, and then perished as the night 
 came on, are preserved in a state of perfect entireness. 
 In the amber of Prussia eight hundred different kinds 
 of insects have been determined, most of them belonging 
 to species, and even genera, that appear to be distinct 
 from any now known ; while of the others, some are 
 nearly related to indigenous species, and some seem iden- 
 tical with existing forms that inhabit the warmer climates 
 of the south.. From their great specific variety and 
 abundance we may infer that insects then, as now, formed 
 the most numerous division of the animal kingdom. Our 
 entomologists reckon at the present time about eleven
 
 140 LECTURES ON- GEOLOGY. 
 
 thousand species of recent British insects, — a number 
 many times greater than that of ail its other denizens 
 of the animal kingdom united. You will scarce deem the 
 riddle regarding the entombment of these fragile crea- 
 tures in the amber, which so puzzled the poet, particularly 
 a hard one : the process must have resembled that which 
 we see going on in our jDine-forests every summer. The 
 little flutterers must have settled on the bleeding trunks 
 of the Pinus siiccinifer, and stuck fast, and the after flow 
 of the sap covered them over. They add an interesting 
 feature, identical with that sung by the jjoet, to the odor- 
 iferous amber forests of the Tertiary. The hot sun is 
 riding high over the recesses of one of these deep woods, 
 never yet trodden by human foot, and lighting up the 
 waved lines of delicate green with which spring, just pass- 
 ing into early summer, has befringed the dark pines, and 
 the yet unwithered catkins of the poplar and plane, and 
 the white blossoms of the buckthorn. The cave-bear and 
 hyena repose in silence in their dens, and not a wandering 
 breeze rustles among the young leafage. 
 
 " But hark ! how throuj;h the peopled air 
 
 The busy murmur fi;lows; 
 The insect youth are on the wing. 
 Eager to taste the honied spring, 
 And float amid the Uquid noon : 
 Some lightly o'er the current skim. 
 Some show their gaily gilded trim 
 
 Quick glaring to the sun." 
 
 And lo ! where the forest glade terminates in a brown, 
 primeval wilderness, the sunbeams fill %vith dazzling 
 brightness on the trunk of a tall, stately tree, just a little 
 touched with decay ; and it reflects the light far and wide, 
 and gleams in strong contrast with the gloom of the
 
 LECTURES ON GEOLOGY. 141 
 
 bosky recesses beyond, like the pillar of fire in the wilder- 
 ness relieved against the cloud of nighty 'T is a decaying 
 pine of stateliest size, bleeding amber. The insects of the 
 hour flutter around it ; and when, beguiled by the grate- 
 ful perfume, they touch its deceitful surface, they fare as 
 the lords of creation did in a long posterior age, in that 
 
 " Serbonian bog, 
 Betwixt Damiata and Mount Casius old. 
 Where armies whole have smile." 
 
 But, as happened to so many of the heroes of classic his- 
 tory, death is fame here, and by dying they became im- 
 mortal ; for it is from the individuals who thus perish that 
 future ages are yet to learn that the species which they 
 represent ever existed, or to become acquainted with even 
 the generic peculianties by which they were distinguished. 
 The question still remains, whence has the amber of 
 our Scottish coasts been derived? It occurs in situ in 
 Tertiary deposits in the neighborhood of London : good 
 specimens of considerable size have been found, for in- 
 stance, in a clay-pit near Hyde Park comer, not a quarter 
 of a mile from the site of the Crystal Palace. It occurs 
 too, in Prussia, in a clay-bed of considerable horizontal 
 extent, of which the larger part lies under the waves of 
 the Baltic, but which rises on some parts of the coast 
 about forty feet over the level of that sea, and to which 
 of late years a sort of classical interest has been given by 
 a modern fiction, worthy, from its air of matter-of-fact 
 truthfulness, of our own Defoe, — the "Amber Witch." 
 The black amber vein found by the pastor's little daughter 
 is described in the story as occurring high in a wooded 
 defile behind her father's parsonage, and as owing its black 
 color to the quantity of charcoal, i. e., carbonized wood,
 
 142 LECTURES ON GEOLOGY. 
 
 which it contained. And in both particulars the descrip- 
 tion is true to the geology of the amber deposits. But 
 we have no amber deposits in Scotland ; had amber ever 
 existed in connection with the Tertiary beds of Mull, it 
 would have shared, in all probability, from the close prox- 
 imity of the trap, the fate of the great lumps of butter 
 which that giant in the nursery story who used to eat 
 knights and young ladies, employed in testing the heat of 
 his oven; and so we must look for its place, not on our 
 chores, but in the seas by which they are washed. But it 
 n here necessary that I shotdd submit to you a brief out- 
 line of the structural geology of our country, not only 
 that we may knoAv in what direction to look for its Ter- 
 tiary beds, but in order also that we may foi-m such an 
 acquaintance with the general framework of our subject, 
 as it exists in space, as may guide us in all our after con- 
 ceptions regarding it. Avoiding the prolixity of minute 
 detail, I shall present you at present with but a few of the 
 leading lines. 
 
 The great central nucleus of Scotland, presenting con- 
 siderably more than fifteen thousand square miles of sur- 
 face, consists of what we shall term, w^ith the elder geol- 
 ogists, primary rocks, — granites, gneisses, mica-schists, 
 quartz-rocks, and clay-slates. These extend in one direc- 
 tion from the southern base of the Grampians to the 
 northern limits of Sutherlandshire, and fi-om Peterhead 
 and Aberdeen on the east to Glenelg and Loch Carron on 
 the west. [Now, aroimd this great primary mass there runs 
 a ring of the sedimentary fossiliferous rocks, somewhat, 
 though of course not Avith such unbroken regularity, as a 
 frame runs round a picture, or as the metallic setting of a 
 Cairngorm or pebble brooch surrounds the stone. Of 
 these earlier fossiliferous rocks, known about the begin-
 
 LECTURES ON GEOLOGY. 14.3 
 
 ning of the present century as the Grauwacke, and now 
 as the Sihirians, the frame or ring contains but fragments, 
 — a narroM' strip along the flanks of the Grampians on the 
 south, and a few detached patches along the shores of 
 Banff on the north and east. But the ring or frame of 
 the next oldest fossiliferous system, the Old Red Sand- 
 stone, is very nearly complete ; and to such a breadth do 
 we find it developed, especially in the southern and north- 
 ern parts of the inclosing frame, that, with the addition of 
 a few patches in the border counties of Scotland, we find 
 it occupying nearly five thousand square miles of the sur- 
 face of our country.'] Outside the Old Red Sandstone 
 frame there occurs to the south, in the line of the great 
 flat valley which runs across the country from the Frith 
 of Forth to that of the Clyde, a broad belt of the Coal 
 Measures, — the system which succeeds to it in natural 
 sequence ; but on the east, west, and north, the Coal Meas- 
 ures and New Red Sandstone are wanting, and we find 
 fragments of a ring of Lias, as at Applecross, on the one 
 coast, and at Cromarty and Shandwick on the other ; and 
 outside the Lias, considerable fragments of yet another 
 and wider ring of the Oolite. The sea on the east coast, 
 and both that and numerous outbursts of overlying trap 
 
 1 The Old Red Sandstone frame, and its coiTesponding illustrations, no 
 longer hold good. The geology of north-western Scotland has recent].y 
 been investigated by Sir Roderick Murchison, from whose researches it 
 appears that Silurian strata occupy a much wider area of that district than 
 had been previously suspected. Aided by Mr. Peach's discovery of Lower 
 Silurian fossils in the crystalline limestones of Sutherlandshire, Sir Roder- 
 ick has succeeded in showing that from the Atlantic to the German Ocean 
 there is a regular succession of strata in ascending order, representing the 
 Laurentian gneiss of Canada and the Cambrian and Lower Silurian rocks 
 of Wales, and superposed upon these older formations in the great Old 
 Red Sandstone of Caithness. See the abstract of Sir Roderick Murchison's 
 paper in the Reports of the Leeds Meeting of the British Association. — G.
 
 144 LECTURES ON" GEOLOGY. 
 
 on the west, covers up the ring which lies beyond ; but 
 the Chalk flints and Greensand fossils of Aberdeen and 
 Banff shires on the one hand, and the Chalk flints of Mull 
 and Caithness on the other, indicate its existence and its 
 components. An outer ring or frame of Chalk and Green- 
 sand, more or less broken, surrounds on two, mayhap on 
 three sides, the central nucleus of the kingdom ; and were 
 the beds of the German and Atlantic Ocean to be laid dry 
 to the depth of about fifty fathoms, and the area of Scot- 
 land to be proportionally extended, you would find for- 
 mation succeeding formation, in crossing the ring from the 
 nucleus outwards, as we find them succeeding each other 
 in the south of England, when crossing the country from 
 South Wales in the direction of London. Beyond this 
 outer ring of Chalk there lie, it is more than probable, 
 deposits of the Tertiary system. Of the Mull deposits on 
 the west coast we at least know, though tliey occur in so 
 disturbed and overflown a district, that they lie outside 
 the Secondary deposits of the island; and again on the 
 east coast, where the Tertiary deposits, which occupy so 
 large a portion of the south-eastern portion of England, 
 outside the Chalk, lose themselves in the German Ocean, 
 the dredoje has found interesting trace of them far at sea 
 running northwards, to form, apparently, our submarine 
 belt or ring. It is stated by Woodward, in his " Geology 
 of Norfolk," that the oyster-fishers on that coast dredged 
 up from a tract of oyster-beds near Ilappesburgh no fewer 
 than two thousand grinders of mammoths in the course of 
 thirteen years. Further, those parts of the Continent 
 which lie opposite our eastern coasts, including Holland, 
 Hanover, and the larger part of Denmark, all consist of 
 deposits of the Tertiary system, which, trending westwards 
 at a low angle, form, it is probable, no inconsiderable part
 
 LECTURES ON GEOLOGY. 145 
 
 of the bed of the German Ocean. Those beds, however, 
 from which our Scottish amber is derived must lie deep in 
 the sea, outside the Lias, the Oolite, the Greensand, and 
 the Chalk ; and our specimens are rare in consequence, 
 because at great depths the bottom is little affected by 
 tempests. Not less than eight hundred pounds weight of 
 this substance has been thrown u]) on the coast of east 
 Prussia by a single storm. 
 
 Fi-om the Tertiaries we would naturally pass, in our 
 upward progress, to the Secondary deposits ; and of these, 
 the remains of the Cretaceous system, as exhibited in 
 Banff and Aberdeen shires, would, of course, first solicit 
 notice, as rej^resentative in Scotland of that portion of the 
 Secondary period nearest our own, — the period with 
 which this great middle division of the earth's history 
 terminated. I must first, however, call your attention to 
 a series of rocks which, without belonging to any of the 
 three great sedimentary divisions, seem in our own coun- 
 try to have been contemporary with them all. I refer to 
 the trap rocks of the kingdom. The Duke of Argyle 
 found in the island of Mull, as has been already shown, 
 thick beds of trap, tuffacious and basaltic, overlying beds 
 of the Tertiary division. Again, in the Isle of Skye, Pro- 
 fessor Edward Forbes has detected trap beds which made 
 their way to the surface, and ovei-flowed the shells and 
 corals of the Oolite, about the middle of the great Sec- 
 ondary period. "The thick sheet of imperfectly columnar 
 basalt," says the Professor, " which has so wide an exten- 
 sion in the island of Skye, and plays so important a part 
 in the formation of the magnificent scenery of its coasts, 
 Avas the i:)roduct of a submarine eruption, which, if we 
 regard the basalt as an overflow, has its geological date 
 marked to a nicety, having occurred at the close of the 
 
 ]3
 
 146 LECTURES ON GEOLOGY. 
 
 middle and at the commencement of the upper Oolitic 
 period." Yet again, in the neighborhood of Edinburgh, 
 as well described by Mr. Charles M'Laren, there are traps 
 of the Palaeozoic division, — beds of stratified tuff, as 
 among the rocks of the Calton Hill, for instance, — that 
 belong to the early part of the Carboniferous period ; and 
 I have seen at Oban a conglomerate low in the Old Red 
 Sandstone, formed chiefly of a trap, Avhich even at that 
 early time must have been a surface rock much exposed to 
 denudation. We must regard, then, the trap rocks of 
 Scotland as of all ages, from the earlier Pala30zoic to the 
 middle Tertiary jDcriods. The great ganoidal fishes of the 
 Devonian and Carboniferous ages, the huge reptiles of the 
 Oolite, and the gigantic mammals of the Miocene, must 
 have been exposed, in turn, in what is now Scotland, to 
 deluging outbursts of molten matter from the vexed bow- 
 els of the earth, and to overwhelming showers of volcanic 
 ashes. 
 
 I would, however, crave attention to the curious fact, 
 that during this immensely protracted period of Plutonic 
 activity, the deep-seated agencies operated in nearly the 
 same lines. Masses of the incarcerated matter seem to 
 have made their escape age after age along the same weak 
 parts of their prison walls, — the earth's crust; and in 
 Scotland we have two of those lines of apparent weakness 
 wdiich converge in a greatly overflown district in the north 
 of Ireland. One of these lines runs along i\ui inner Heb- 
 rides nearly south and north, and includes in its area, as 
 distinct centres of Plutonic action, the islands of Skye 
 and of Mull, Avith what are known as the Small Isles lying 
 between, and the promontory of Ardnamurchan. The 
 other line sweejts across the country from noi-th-eaist to 
 south-west, commencing at Dunbar on the east, an i ter-
 
 LECTURES ON GEOLOGY. 147 
 
 minating, in Scotland, witli AiTan and Carapbelton on the 
 west ; but running, as I have said, across the Irisli Sea, it 
 reappears in Ulster. It includes, among many lesser trap 
 eminences, the Cam2:)sie, the Ochil, and the Lomond hills ; 
 the eminences also on which the castles of Stirling and 
 Dumbarton are built; the hills which give character to 
 the scenery around Edinburgh, — Corstorphine, Blackford, 
 the Pentlands, the Castle rock, the Calton, Salisbury Crags, 
 and Arthur's Seat ; and far to the east, that Haddington 
 group of trap hills to which North Berwick Law, the Bass, 
 and the Isle of May belong. Beyond these great lines of 
 injected cracks and filled-up craters, especially to the 
 north and east, there are wide districts in Scotland in 
 which there does not occur a single trap rock. The lava- 
 like flood found its way to the surface from the fiery depths 
 beneath, through the chinks and crannies which we now 
 find indicated by the dikes and insulated stacks and hills 
 of what we may terra the Lothian and Hebridean lines, 
 and through these only; and those portions of the Low- 
 lands of Scotland which lie to the north of the Grampians, 
 such as the plains of Caithness, Moray, and Easter Ross, 
 present, from the absence of the trap, an entirely different 
 character from that exhibited by the Lowlands ol the 
 South. 
 
 The igneous rocks have been divided, according to oheir 
 mineral or mechanical character, into tuffs, amygdajoids, 
 porphyries, dolerites^ claystones, clinkstones, wackes, tra- 
 chytes, and various other species. For our present pur- 
 pose, however, and as adequate to the demands of our 
 necessarily brief and imperfect sketch, we may regard the 
 trap rocks as consisting of but two great divisions, — lirst, 
 the traps proper, including all igneous masses, from the 
 porphyries to the basalts, which were ejected from fho
 
 148 LECTURES ON GEOLOGY. 
 
 abyss in a molten form, and which either ovei*flowed from 
 ilieir vents and craters certain portions of the earth's sur- 
 face, whether subaqueous or subaerial, or, forcing their way 
 between strata of the sedimentary rocks, formed among 
 them dikes, or beds, or pillar-like masses; and secondly, 
 trap-tuffs, which, though igneous in their components, were 
 ejected from craters in the form of loose ashes and de- 
 tached fragments, or were ground down by the agency of 
 water, and subsequently arranged in regular strata under 
 the same laws which have given their stratification to the 
 rocks of aqueous origin amid which we so frequently find 
 these trap-tuffs intercalated. You will at once see that 
 the division here is a natural one. There is a wide differ- 
 ence betwixt a stratum of broken glass and scoriae, the 
 debris of a glass-house ari-anged by the tide on the beach 
 on which it had been cast down a few hours before, and a 
 continuous eheet of plate-glass still retaining its place in 
 the mould into which it had been run off by sluices from 
 the furnace. And such is the difference between ti"ap-tuff 
 and trap proper. We have to arrive, too, when we find 
 them occurring, as in this neighborhood, among the rocks 
 of a district, at very different conclusions regarding their 
 date and history. Without inquiring whether in some 
 rare instances an eruption of volcanic mud might not possi- 
 bly be ejected, by a sort of hydraulic-press process, between 
 strata of previously existing rock, and thus a tuff bed come 
 to be formed which was not only newer than the stratum 
 on which it rested, but also than that by whi^h it was 
 overlaid, we mny receive it as a general fact, that tlie true 
 tuff-bed, like beds of the ordinary sedimentary rocks, is 
 more modern than the stratum on wliich it rest&, and more 
 ancient than the stratum which overlies it ; that if it oc- 
 cur, for instance, among the Old Red Sandstones, it belongs
 
 LECTURES ON GEOLOGY. 149 
 
 to the age of tlie Old Red Sandstones ; if among the Coal 
 Measures, to the age of the Coal Measures ; and if among 
 the Oolites, to the age of the Oolites. But we cannot 
 predicate after the same fashion, that the bed of trap 
 proper which we find resting over one series of sediment- 
 ary strata and under another is of nearly the same age as 
 the rock above and below, or just a little older than the 
 upper and a little newer than the nether ones. It may 
 have been injected among them many ages after their 
 deposition, during even an entirely different period of the 
 earth's history. "We may safely infer, that those beds of 
 stratified trap-tuflf which alternate in the Calton Hill with 
 beds of trap-porphyry belong to the Carboniferous period, 
 and are very considerably older than the overlying sand- 
 stones and shales on which Regent Terrace is built ; but 
 we can no more infer that the great bed of greenstone 
 which forms the picturesque crown of Salisbury Crags is 
 of the same age as the rocks among which it occurs, or, 
 more strictly, a little newer than the strata below and 41 
 little older than the strata above, than we can infer that a 
 cast-iron wheel or axle is of the same age as the mould into 
 which it was run, or, more strictly, a little newer than the 
 bottom of the mould, and a little older than the top of it.^ 
 Let us now devote a brief space to the consideration of 
 
 1 The usual test of the age of these melted traps is the relation they 
 bear to the rocks which overlie thera. If the part of the superjacent bed 
 resting on the igneous rock present an altered appearance, as if it had 
 been more or less baked in a furnace, the trap is regarded as intnisii-e, that 
 is, it forced its way between the planes of the sti'ata, and must conse- 
 quently be of later age. If, on the other hand, the beds above display no 
 symptom of alteration, and more especially if they consist of trap-tuff, the 
 underlying igneous rock may be presumed to have been erupted eitlier under 
 water or in open air, as the case may be : and hence it is regarded as in a 
 general way contemporaneous with the strata among which it occurs - ■ G. 
 
 13*
 
 150 LECTURES ON GEOLOGY. 
 
 the scenery usually associated with the trap rocks, — a 
 subject which should possess some little interest to an 
 Edinburgh audience, seeing that their most magnificent 
 of cities owes almost all that is imposing and peculiar in 
 its aspect and appearance to this cause. The scenery of 
 a trap district may be resolved into two components. In 
 an ancient ruin we frequently see stones hollowed by decay 
 into a sort of flmtastic fretwork, not very unlike that 
 which roughens some of our more ancient runic obelisks; 
 and we recognize as the cause of these irregularities of 
 surface on which the effect depends, certain original ine- 
 qualities in the texture of the mass, and certain weather- 
 ing influences, which, while they wore away the softer jjor- 
 tions, spared such as were harder and more durable. And 
 such, on a larger scale, are the two elements operative in 
 the production of the ijeculiarities of trap scenery. The 
 hard trap rocks injected into the comparatively soft sand- 
 stones and shales of a district, such as that which sur- 
 i«ounds the Scottish capital, compose a mass of very various 
 texture and solidity, which, if operated upon equally by 
 some power analogous to the weathering one in the case 
 of the fretted stone, Avould necessarily yield unequally ; 
 and the weathering influences we find represented on the 
 large scale by the denuding agencies. The noble eminen- 
 ces which give character and individuality to our city 
 were literally scooj^ed out of the general mass by tides, 
 and waves, and deep-acting currents, as the sculptor chis- 
 els out his figures, in executing some piece in alto relievo^ 
 by chipping away the surrounding plane. The bold ligure 
 of the poet Hogg becomes almost a literality liere: 
 
 " Who was it srooped tliesc stony Wivves? 
 Who yciil))M the Ijrows of old Ciiirugorm, 
 And dii;;' tlictsc cvt-r-yawninj; caves? 
 'T was I, the spirit of the storm."
 
 LECTURES ON GEOLOGY. 161 
 
 The masses of enclosed trap are of various forms. Some- 
 times they occur as deeply-based pillar-like masses, filling 
 up, it is i)ossible, ancient craters. The rock of hard clink- 
 stone on which the Castle of Edinburgh stands is one of 
 these ; but the long-inclined plane of sedimentary deposits 
 which it shielded from the wear of the western current 
 interferes Avith its column-like outline. The Bass rock is 
 an example of the same kind, with no sedimentary tail to 
 mar the effect of its natural outline. The dike is another 
 and yet more characteristic form of trap rock : it is a rock 
 that was moulded in a longitudinal crack or rent, as the 
 other was moulded in a well-like crater ; and when the 
 original matrix in which it was cast has been washed from 
 its sides, and it remains standing up over the level, it 
 assumes the wall-like or dike-like form to which it owes its 
 name. In sailing along the west coast of Scotland in a 
 clear sunny day, that gives to each projecting crag its 
 deep patch of shadow, these fragments of walls, of vastly 
 more ancient date than the oldest and most venerable of 
 our Scottish ruins, may be seen rising fi-om the beach 
 along the faces of gi-assy banks or rounded tuft-formed 
 precipices, and communicating to the general scenery one 
 of its most characteristic features. But one of the main 
 scenic peculiarities of the trap districts is derivable from 
 their trap beds. We find in this neighborhood, among 
 the hills of the Queen's Park, bed rolled over bed, with 
 bands of shale, or sandstone, or soft trap-tuff, between ; 
 and these beds, ranged often in nearly parallel lines, and 
 bared by the denuding agencies, present not unfrequently, 
 seen in profile, the appearance of a flight of steps. Hence 
 the generic name for this class of rocks, — trappa, a stair: 
 the traps are the stair-like rocks. As seen in a calm, clear 
 morning, from nearly the cu,steni teniiination of Ifcgent
 
 152 LECTURES ON GEOLOGY. 
 
 Terrace, the Arthur Seat group of hills exhibits three 
 of these beds ranged for considerable distances in nearly 
 parallel lines, and, -with these, well-marked fragments of 
 several others. First, reckoning from the west or south, 
 there is the continuous greenstone bed of Salisbury crags ; 
 next, the partially-broken bed of greenstone jDorphyry 
 known as the Bay Crag; next, the continuous bed of 
 compact greenstone known as the Hill Crag, — that along 
 the top of which the path ascends to the summit of Arthur 
 Seat from St. Anthony's Well; and then there are at least 
 two beds of basalt, partially sanded over, which rise in 
 interrupted steps along the face of the eastern hill. These 
 beds form the peculiar feature of the fine fragment of land- 
 scape which from this point of view the Arthur Seat group 
 of hills composes.^ The trap scenery may be described 
 generally as eminently picturesque. From the circum- 
 stance that its eruptive masses rise often from amid level 
 fields, and that its hard abrupt beds, dikes, and columns, 
 alternate oflen with rich, soft strata, that decompose into 
 fertile soils, it abounds in striking contrasts. The soft 
 plain ascends often at one stride into a hill fantastically 
 rugged and abrupt ; and bare and fractured precipices 
 overtop terraced slopes or level platforms, rich in verdure. 
 Some of the more famed scenery of England owes its 
 beauty to the ti-ap rocks. Hagley, the seat of the Lyttle- 
 tons, so celebrated in the English poetry of the last cen- 
 tury for its beauty, is situated half on a range of pictur- 
 esque trap hills, half on a level plain of the New Red 
 Sandstone; and the fai--famed view from the Leasowes 
 
 ^ On the west coast of Mull, and the islands of Gomctra and Ulva, six 
 or cijjlit of tliese step-like beds may be seen, rising the one over the 
 other, like terraces or stories in a building; and the whole landscape 
 seems barred with right lines, that iii this district lie ncoi-ly parallel to the 
 horizon.
 
 LECTURES ON GEOLOGY. 153 
 
 owes much of its beauty to the traps of the Clent Hills. 
 But it would be unpardonable, in treating, however 
 slightly, of the scenery of the trap, to omit all refer- 
 ence to one of its strangest features, — those of ranges 
 of polygonal columns which, in at least the more perfect 
 specimens are peculiar to it, and which impai't to dame 
 Nature, in so many instances, those qualities of propor- 
 tion and regularity in which art alone can pretend to 
 vie with or surpass her. The specimens in our own 
 neighborhood are either of small extent, as in Samson's 
 Ribs, or both that and of imperfect form, as at St. An- 
 thony's Chapel and in the adjacent hill-front; but I have 
 seen in the neighborhood of Linlithgow a range of slender 
 columns sufficiently regular to have given rise to a tra- 
 ditional myth in the locality, that they owe their oiigin 
 to the ingenuity of the old Picts; and the columned 
 scuir of Eigg greatly surpasses in grandeur the far-famed 
 Giants' Causeway, and scarce falls short of it in the sym- 
 metry of its strange architecture. To that wondrous 
 ocean cave of the west which an enlightened age con- 
 tinues to recognize as one of the marvels of Scotland, 
 I need but refer in the graphic verse which the Ettrick 
 Shepherd has transferred, in his "Queen's Wake," to 
 "Allan Bawn, the bard of 3Iull." 
 
 " A'wed to deep silence^ they tread the strand, 
 Wlaere fumaccd pillars in order stand; 
 All framed of the liquid burning levin, 
 And bent like the bow that spans the heaven; 
 Or upright ranged, in wondrous array. 
 With purple of green o'er the darksome gray. 
 The solemn rows in that ocean den 
 Were dimly seen like the forms of men; 
 Like giant monks in ages agone, 
 Whom the god of the ocean had sear'd to stone; 
 And their path was on wondrous pavement old. 
 In blocks all cast in some giant mould."
 
 154 LECTURES ON GEOLOGY. 
 
 The old scenery of the trap rocks of Scotland, — the 
 scenery associated with them when our country, along at 
 least its two great lines of trappean eruption, was a Terra 
 del Fuego, — a land of fire, — it would require some of 
 that poetic faculty to restore which I would fliin challenge 
 for the geologist. Even in the immediate neighborhood 
 of the capital, the rocky crust of the earth has been 
 heaved into vast waves by the imprisoned Plutonic agen- 
 cies struggling for vent; huge floods of molten matter, 
 now hardened into mountain masses, have been injected 
 ■with earthquake throes between tlie folds of the stony 
 strata; and a submarine volcano has darkened the heavens 
 with its ashes, shutting out during the day the light of 
 the sun, and throwing its red gleam, when the night had 
 fallen, over the steaming eddies of a boiling and broken 
 sea. The area which we now occupy has heaved like the 
 deck of a storm-beset vessel; the solid earth has been 
 rent asunder; and through the wide cracks and fissures, 
 now existing as greenstone dikes, the red molten matter 
 has come rushing through. Could we this evening ascend 
 into the remote past, when that picturesque eminence 
 which overlooks Edinburgh, — according to the poet 
 Malcolm, 
 
 " Arthur's craggj' bulk, 
 That dweller of the air, abrupt and lone," — 
 
 was, like the son of Semele, first ushered into the world 
 amid smoke and flame, you would find the scene such 
 as poets might well desire to contemplate, or solicit the 
 aid of their muse adequately to describe. For many ages, 
 what now exists as the picturesque tract of hill and valley 
 attached to old Holyrood, and to which the privileges 
 of the court still extend, liad existed as a tract of shallow 
 sea, darkened, when the tide fell, by algaj-covered rocks
 
 LECTURES OX GEOLOGY. 155 
 
 and banks, and much beaten by waves. From time im- 
 memorial has the portion of the earth's crust which under- 
 lies that shallow sea been a scene of deep-seated igneous 
 action. Vast beds of trappean rock — greenstone, and 
 columnar basalt, and aniygdaloidal porpliyry — have been 
 wedged from beneath, as molten injections, between the 
 old sedimentary strata; vast waves of translation have 
 come rolling onwards from that disturbed centre, as some 
 submarine hill, elevated by the force of the fiery injection 
 — as the phitform of a hydraulic press is elevated when 
 the pump is plied — has raised its broad back over the 
 tide, only, however, to yield piecemeal to the denuding 
 currents and the storm-raised surf of centuries. And 
 now, for day after day has there been a succession of 
 earthquake shocks, that, as the plutonic paroxysm in- 
 creases in intensity, become stronger and more frequent, 
 and the mountain waves roll outwards in ever-widening 
 circles, to rise and fall in distant and solitary seas, or 
 to break in long lines of foam on nameless islands un- 
 known to the geographer. And over the roar of waves or 
 the rush of tides we may hear the growlings of a subter- 
 ranean thunder, that now dies away in low, deep mutter- 
 ings, and now, ere some fresh earthquake-shock tempests 
 the sea, bellows wildly from the abyss. The billows fall 
 back in boiling eddies ; the solid strata are upheaved 
 into a flat dome, crusted with corals and shells ; it cracks, 
 it severs, a dark gulf yawns suddenly in the midst ; a 
 dense, strongly variegated cloud of mingled smoke and 
 steam arises black as midnight in its central volumes, 
 but chequered, where the boiling waves hiss at its edge, 
 with WTeaths of white ; and anon with the noise of many 
 waters, a broad sheet of flame rushes upwards a thousand 
 fathoms into the sky. Vast masses of molten rock, that
 
 156 LECTURES ON GEOLOGY. 
 
 glow red amid even the light of day, are hurled into the 
 air, and then, with hollow sound, fall back into the chasm, 
 or, descending hissing amid the vexed waters, fling high 
 the hot spray, and send the cross circlets of wave which 
 they raise athwart the heavings of the huger billows pro- 
 pelled from the disturbed centre within. The crater rises 
 as the thick showers of ashes descend; and amid the 
 rending of rocks, the roaring of flames, the dashings of 
 waves, the hissings of submerged lava, and the hollow 
 grumblings of the abyss, the darkness of a starless night 
 descends ujDon the deep. Anon, and we are startled by 
 the shock of yet another and more terrible earthquake ; 
 yet another column of flame rushes into the sky, casting a 
 lurid illumination on the thick rolling reek and the pitchy 
 heavings of the wave; seen but for a moment, we may 
 mark the silvery glitter of scales, for there is a shoal of 
 dead fish floating past ; and as the coruscations of an 
 electric lightning darts in a thousand fiery tongues from 
 the cloud, some startled monster of the deep bellows in 
 terror from the dank sea beyond. 
 
 Let us raise the curtain once more from over the past of 
 the trap districts of Scotland. Myriads of ages have 
 come and gone ; the submarine volcano has been long 
 extinguished ; and the land, elevated high over the waters, 
 has become a scene of human habitation. But the wild 
 country, marked by the well-known features of abrupt 
 precijjitous hill and deep retiring valley, is roughened 
 by many a shaggy wood, and gleams with many a blue 
 lochan, and even its richer plains are but partially broken 
 up by the plough. And lo ! the trappean centres of the 
 district are scenes of fierce war, as of old ; but it is not 
 the dead uninformed elements, — fire, earth, and watei', — 
 but energetic, impassioned man, that now contends, and
 
 LECTURES ON GEOLOGY. 157 
 
 in fierce warfare battles, with his kind. Yonder, on its 
 trap rock, once the crater of a volcano, is the fortress of 
 the Bass, the stronghold that last surrendered in Britain 
 to "William of Nassau ; and yonder, on its trap rock, 
 the castle of Dunbar, that brave black Agnes held out 
 in so determined a spirit against the English ; and yonder, 
 on its trap rock, the castle of Dirleton, which stood siege 
 in behalf of our country against Edward I. ; and yonder, 
 on its trap rock, scaled by Lord Randolj^h of old when he 
 wan-ed for the Bruce, is the castle of Edinburgh, the 
 scene of a hundred fights, and surrounded by the halo 
 of a thousand historic associations ; and yonder, on its 
 trap rock, is the castle of Stirling, with the battle-ground 
 of Scotland at its feet, and to maintain which against 
 the greatest of our Scottish kings, the second Edward 
 vainly fought the battle of Bannockburn ; and yonder, on 
 its trap rock, is the castle of Dumbarton, long impregna- 
 ble, but which the soldier of the Reformation won at such 
 fearful risk from the partisans of Mary. I remember at 
 one time deeming it not a little curious that the early 
 geological history of a country should often, as in this 
 instance, seem typical of its subsequent civil history. If 
 a country's geologic history had been very disturbed, — if 
 the trap rock had broken out from below, and tilted up its 
 strata in a thousand abrupt angles, steep precipices, and 
 yawning chasms, I found the chances as ten to one that 
 there succeeded, when man catne upon the scene, a his- 
 tory, scarce less disturbed, of fierce wars, protracted sieges, 
 and desperate battles. The stormy morning during which 
 merely the angiy elements had contended, I found suc- 
 ceeded in almost every instance by a stormy day, mad- 
 dened by the turmoil of human passion. But a little re- 
 flection dissipated the mystery ; though it served to show 
 
 14
 
 158 LECTURES ON GEOLOGY. 
 
 through what immense periods mere physical causes may 
 continue to operate with moral effect, and how, in the 
 purposes of Him who saw the end from the beginning, a 
 scene of fiery confusion — of roaring waves and heaving 
 earthquakes, of ascending hills and deepening valleys — ■ 
 may have been closely associated with the right develop- 
 ment and ultimate dignity and happiness of the moral 
 agent of creation, — unborn at the time, — reasoning, re- 
 sponsible man. It is amid these centres of geologic dis- 
 turbance, the natural strongholds of the earth, that the 
 true battles of the race, the battles of civilization and civil 
 liberty, have been successfully maintained by handfuls of 
 hardy men, against the despot-led myriads of the plains. 
 Ill glancing over a map of Europe and the countries 
 adjacent, on which the mountain groups are marked, you 
 will at once perceive that Greece and the Holy Land, 
 Scotland and the Swiss cantons, formed centres of great 
 jilutonic disturbance of this character. They had each 
 their geologic tremors and perturbations, — their pro- 
 tracted periods of eruption and earthquake, — long ere 
 their analogous civil history, witli its ages of convulsion 
 and revolution, in which man was the agent, had yet com- 
 menced its course. And, indirectly at least, the disturbed 
 civil history was in each instance a consequence of the 
 disturbed geologic one. 
 
 From the Teitiary deposits we pass direct to the feW 
 scattered remains which survive in Scotland of the Cre- 
 taceous period. It is now nearly thirty years since it was 
 found by geologists that chalk flints inclosing in many 
 specimens the peculiar organisms of the system, occur in 
 the superficial deposits of Banff and Abcrdeenshires ; and 
 about three years ago they were also discovered by a very 
 ingenious man, a Thurso tradesman, Mr. Robert Dick, in
 
 LECTURES ON GEOLOGY. 159 
 
 the boukler-cLiys of Caithness. It is, however, a curious 
 fact, that what the geologist has only come to know mthin 
 the course of the present generation was well known to 
 the wild aboriginal inhabitants of the country some three 
 or four thousand years ago. Well-nigh one half the 
 ancient arrow and smaller javelin heads of the stone- 
 period in Scotland, esjiecially those found to the north 
 of the Grampians, were fashioned out of the yellow Aber- 
 deenshire flints. A history of those arts of savage life 
 which the course of discovery served to supplant and 
 obliterate, but wliich could not be carried on without a 
 knowledge of substances and qualities afterwards lost, 
 until re-discovered by scientific curiosity, would form an 
 exceedingly curious one. On finding, a good many years 
 ago, a vein of a bituminous jet in one of the ichthyolite 
 beds of the Old Red Sandstone of Ross, — beds miknown 
 at the time to even our first geologists, — it curiously 
 impressed me to remember tliat my discovery was, after 
 all, only a discovery at second-hand ; for that in an un- 
 glazed hand-made urn of apparently a very early j^eriod, 
 dug up in the neighborhood only a few years before, 
 there had been found a very primitive necklace, fashioned 
 out of evidently t)ie same jet. It would seem that to 
 these ichthyolite beds, unknown at the time in the district 
 to all but myself, the savage inhabitants had had recourse 
 for the materials for their rude ornaments thousands of 
 years before. They were mineralogists enough, too, as 
 their stone hatchets and battle-axes testify, to know where 
 the best tool and Aveapon-making rocks occur ; and I once 
 found in a northern locality a battle-axe of an exceeding 
 strong and toiigli variety of indurated talc, that nearly 
 apjn'oached in character to the axe-stone of Werner, which, 
 if native to Scotland at all, is so in some primary district
 
 160 LECTURES ON GEOLOGY. 
 
 which I am not mineralogist enough to indicate. It 
 shows us after how strange a fashion extremes may 
 meet, — that rucle savages, ignorant of the use of the 
 metals, and the scientific explorers of a highly civilized 
 age, rationally desirous to know how the adorable Creator 
 wrought ujDon this earth of old, ere man had yet entered 
 upon it as a scene of probation, should have formed an 
 acquaintance with the same class of objects, — classes of 
 objects of which the men of an intervening j)eriod knew 
 nothing. 
 
 The chalk fragments and flints of Caithness and Banff 
 seem to have been carried eastward on the occidental 
 current of the Pleistocene period, — those of the one 
 county from that western portion of the chalk ring or 
 girdle to which I have already referred as lying in the 
 Atlantic, and those of the other from that eastern portion 
 of the ring which is buried in the outer reaches of the 
 Moray Frith. In Aberdeenshire, however, some twenty 
 miles or so to the north of the city, in the parish of Ellon 
 and some of the contiguous parishes, and running at a 
 considerable distance inland in a line nearly parallel to 
 the coast, the flints so abound, and, unlike those of the 
 English gravels, are so little water-worn as to give evi- 
 dence that they must have been derived from the disinte- 
 gration of outliers of the system that once existed, it is 
 probable, in their immediate neighborhood. They over- 
 lie, too, in some parts of this locality, what seems to be a 
 re-formation of the greensand ; of which the soft, inco- 
 herent masses, containing, as they do, in some, in a good 
 state of keeping, some of the more fragile organisms of 
 the deposit, could not possibly have travelled far. The 
 fossils of our chalk flints and of the underlying greensand 
 are sufficiently numerous and characteristic to serve the
 
 LECTURES ON GEOLOGY. 161 
 
 purpose of identifying the worn and scattered deposits in 
 which they occur with the amply developed chalks and 
 greensands of England, but perhaps not sufficiently so, nor 
 yet always in a sufficiently fine state of preservation, to 
 render the district a very hopeful scene of labor to the col- 
 lector desirous absohitely to extend our knowledge of the 
 extinct forms of life. I have seen, however, especially in 
 the collections of Dr. Fleming, the Rev. Mr. Longmuir, of 
 Aberdeen, and Mr. Fergusson, of Glasgow, fine and very 
 characteristic specimens of the Scotch Chalk, — delicate 
 flustra sponges and corals locked up in flint, — well- 
 marked portions of the sea-egg order (Echinidfe) belong- 
 ing to the cidarite, galerite, and spatangus families, — ■ 
 terebratuloB of various species, — good specimens of that 
 very characteristic conchifer of the Chalk, the Inoceramus, 
 — with casts of minute belemnites and portions of ammo- 
 nites and baculites. The group of remains preserved is 
 unequivocally that of the Cretaceous fauna, just as Scot- 
 land has also a group of archaeological remains decidedly 
 Roman ; though in either ease these remains serve but for 
 purposes of identification with larger groups elsewhere : 
 and in order thoroughly to study either the one or the 
 other, the antiquary or geologist would have to remove 
 from what is equally the outskirts of the old Roman or 
 old Cretaceous empire, towards its centre in the south. 
 
 All our geologists agree in holding that the Chalk was 
 deposited in an ocean of very considerable depth, and of 
 such extent that it must have covered for many ages the 
 greater part of what is now southern and centi-al Europe. 
 It has been traced in one direction from the north of Ire- 
 land to the Crimea in Southern Russia, a distance of about 
 twelve hundred miles ; and in another direction from the 
 south of Sweden to the southwest of France, a distance of 
 
 14*
 
 162 LECTURES ON GEOLOGY. 
 
 about nine hundred miles ; and there are extensive districts 
 both in France and England where it attains to an average 
 thickness of not less than a thousand feet. The only anal- 
 ogous deposit of the present time occurs on comparatively 
 a small scale among the coralline reefs and lagoons of the 
 Pacific, where there is in the act of forming a)A impalpable 
 white mud derived from the corals, which in iried speci= 
 mens cannot be distinguished by the unassist I eye from 
 masses of soft chalk. But what chiefly distinguishes the 
 true chalk from any of its modern representatives is the 
 amazing number of microscopic animals Avhich it contains. 
 On a low estimate, half its entire bulk is composed of 
 animalculites of such amazing minuteness, that it has been 
 calculated by Ehrenberg that each cubic inch of chalk mny 
 contain upwards of a million of the shells of these crea- 
 tures. The chalk rocks so characteristic of the sister king- 
 dom have been often sung by the jioets as 
 
 " Risinj^ like white ramparts all alonf^ 
 The blue sea's border." 
 
 And, in especial, one " chalky bourn of dread and dizzy 
 summit" has been made by the greatest of jjoets the sub- 
 ject of the sublimest description of a giddy, awe-inspiring 
 precipice ever drawn. And here is there a new associa- 
 tion with which to connect the chalk cliifs of England. 
 Every fragment of these cliifs was once associated with 
 animal life ; that impalpable white dust which gives a 
 milky hue to the waves as they dash against them, consists 
 of curiously organized skeletons ; even the white line which 
 I draw along the board, were our eyes to be suddenly 
 endowed with a liigh microscopic power, would resem- 
 ble i^art of the wall of a grotto covered over with shells. 
 And, embedded in this mass of minute, nicely-framed
 
 LECTURES ON GEOLOGY. 163 
 
 invisibilities, — Polythalaraia, Forarainifera, Polyporia, and 
 Diatoraaceie, — we find fossils of larger size, such as Sjki^ 
 tangus-cor and the spiny Plagiostoma, which seem to 
 have found proper habitats in the mud formed by the 
 dead remains of these aniraalculae. Curious examples of 
 a similar kind may be still seen among the Hebrides, of 
 sand-burrowing molluscs and echinoderms finding habitats 
 amid accumulations of the debris of organic life, chiefly 
 comminuted shells, on coasts where otherwise there could 
 have been no place for them. The deep-sea shells pro- 
 pelled shorewards by the agency of tides and waves are 
 ground down by the action of the surf against the i-ocks. 
 They may be seen occurring in the hollows of the skeri'ies, 
 as one passes shorewards along some of the rocky bays, 
 in handfuls of more and more comminuted fragments, just 
 as, in passing along the successive vats of a paper-mill, one 
 finds the linen rags more and more disintegrated by the 
 cylinders ; and then, within some sheltering shelf or ledge, 
 we find the gathered handfuls of former ages spreading 
 into a wave-rippled beach of minute shelly particles, that 
 presents, save in its snow-white color, the appearance of 
 sandy beaches of the ordinary mineral components. But 
 the beach once formed in this way soon begins to receive 
 accessions from the exuviae of animals that love such 
 localities, — spatangi, razor-fisli, cockles, and the several 
 varieties of the gaper family, — and that enjoy life agree- 
 ably to their natures and constitutions, not the least sad- 
 dened by the idea that they are living amid the rubbish of 
 a charnel-house ; and sometimes one-half the whole beach 
 comes thus to be composed of a class of remains that, save 
 for the previous existence of the other half of it, could not 
 have been formed in such localities at all. Now, such 
 must have been the state of matters in the times of the
 
 164 LECTURES ON GEOLOGY. 
 
 Chalk. Unnumbered millions must have died in order 
 that the medium might be provided in which a class of 
 their successors could alone live. Of the land which 
 skirted this ocean of the Chalk, or of its productions, we 
 know almost nothing. There have been found in Chalk 
 flints a few fragments of silicified wood, and, in one or two 
 instances, the cones of cycadaceous jjlants ; and the upper 
 beds of the system have furnished the remains of a gigan- 
 tic lizard, — the Mosasaurus, with those of turtles, tor- 
 toises, and Pterodactyls. True, the Mosasaurus may have 
 been, as Cuvier supposed, a marine reptile, and the turtles 
 miist have been so ; but then both, as egg-bearing animals, 
 must have brought forth their young on some shore ; and 
 the tortoises, with the Pterodactyl or flying lizard, must be 
 regarded as decidedly terrestrial. Such is almost all we 
 yet know of the flora or fauna of the land of the Chalk ; 
 whereas in marine organisms the system is so exceedingly 
 rich, that its ascertained species amount, we find it stated 
 by Brown, to about three thousand. The geologic dio- 
 rama abounds in strange contrasts. When the curtain last 
 rose upon our country, we looked abroad over the amber- 
 producing forests of the Tertiary jjeriod, with their sunlit 
 glades and brown and bosky recesses, and we saw, far dis- 
 tant on the skirts of the densely wooded land, a fire-belch- 
 ing volcano, over-canopied by its cloud of smoke and 
 ashes. And now, when the curtain again rises, we see 
 the same tract occupied, far as the eye can reach, by a 
 broad ocean, traversed by a pale milky line, that wends its 
 dimpling way through the blue expanse, like a river through 
 a meadow. That milky way of tui-bid water indicates the 
 course of a deep-setting current, that disturbs, far beneath, 
 the impalpable mud of the Chalk. Sailing molluscs career 
 in their galleys of pearl over the surface of this ancient
 
 LECTURES ON GEOLOGY. 165 
 
 8ca; fishes of long extinct species dart with sudden gleam 
 through its middle depths; and far below, on its white 
 floor, the sea urchin creejis, and the spatangus burrows, 
 and crania and terebratulai have cast anchor, and the 
 Crista Galli (or carinated oyster) opens its curiously 
 plicated valves, carved with the zigzag mouldings of a 
 Norman doorway, and the flower-like marsupite expands 
 its living petals. And, dim and distant in the direction 
 of the future Grampians, we may espy a cloud-enveloped 
 island ; but such is its remoteness, and such the enveloping 
 haze, that we can know little more than that it bears along 
 its shores and on its middle heights a forest of nameless 
 trees, unchronicled by the fossil botanist. 
 
 In biinging to a close this part of my subject, let me 
 here remark, that, if we except the obscure and humbly 
 organized diatomaceae, — a microscojiic family of organ- 
 isms which some of our authorities deem animal and some 
 vegetable, and of which hundreds and thousands would 
 find ample room in a single drop of water, — we have 
 now reached a point in the .history of our country, in 
 which there existed no species of plant or animal that 
 exists at the present time. Not a reptile, fish, mollusc, or 
 zoophyte of the Cretaceous system continues to live. We 
 know that it is appointed for all individuals once to die, 
 whatever their tribe or family, because hitherto all indi- 
 viduals have died ; and Geology, by extending our expe- 
 rience, shows us that the same fate awaits on species as on 
 the individuals that compose them. In the one case, too, 
 as in the other, death has its special laws; but the laws 
 which determine the life and death of species seem widely 
 different from those which regulate the life and death of 
 individuals and generations. In general, and with but a 
 few exceptions in favor of the cold-blooded division of the
 
 166 LECTURES ON GEOLOGY. 
 
 vertebrata, the higher order of animals live longest. A 
 man may survive for a hundred years ; an ephemera 
 bursts from its shell in the morning, and dies at night. 
 But it is far otherwise with the higher orders of species. 
 Molluscs and corals outlive the vertebrata; and tribes of 
 the low infusory animals outlive molluscs and corals. We 
 know not that a single shell of at least the latter Pleis- 
 tocene period has become extinct ; but many of its noblest 
 quadrupeds, such as the Irish elk, the cave-bear, tiger, and 
 hyena, and the northern rhinoceros, hippopotamus, and 
 elephant, exist no longer. And as we rise into the remote 
 past, and take farewell, one after one, of even the lower 
 forms, — shells and corals, — and get into a formation all 
 of whose visible organisms are old-fashioned and extinct, 
 we apply the microscope to its impalpable dust, and again, 
 among still humbler and lowlier shapes, find ourselves in 
 the presence of the familiar and the recent. In another 
 sense than that which the old poet contemplated, we learn 
 from the history of species that the most lowly are the 
 most safe. 
 
 " The tallest pines feel most the power 
 
 Of wintry blasts : the loftiest tower 
 Comes heaviest to the ground. 
 
 The bolts that spare the mountain side 
 
 His cloud-cap't eminence divide, 
 And spread the ruin round." 
 
 How long some of these extinct species may have lived 
 we know not, and may never know; but in all cases their 
 term of existence must have been very extended. Even 
 the extinct elephant lived long enough as a species to 
 whiten the plains of Siberia with huge bones, and to form 
 quarries of ivory that have furnished the ivory market 
 for year after year with its largest supplies. And of some 
 of the humbler species of animals, the period during which
 
 LECTURES ON GEOLOGY. 167 
 
 they have continued to Uve must have been vastly more 
 protracted. Cijprina Islandica seems to have come into 
 existence at least as early as the fossil elephant ; and now, 
 thousands of years after the boreal pachyderm is gone, the 
 boreal shell still exists by millions, and evinces no symp- 
 tom of decline. And yet, since the commencement of the 
 great Tertiary division, series of shells, as hardy, appar- 
 ently, as Cyprina, have in succession come into being, and 
 then ceased to be. The period over which we liave passed 
 includes generations of species. But there was space 
 enough for them all in the bygone eternity. It has some- 
 times appeared to me as if, from our own weak inability 
 to conceive of the upper reaches of that awful tide of 
 continuity which had no beginning, and of which the 
 measured shreds and fragments constitute time, we had 
 become jealous lest even God Himself should have wrought 
 in it during other than a brief and limited space, with 
 which our small faculties could easily grapple. 
 
 " Oh, who can strive 
 To cx>niprehend the vast, the awful truth 
 Of t) e eternity that hath gone by, 
 And not recoil from the dismaying sense 
 Of human impotence! The life of man 
 Is summed in birthdays and in sepulchres, 
 But the eternal God had no beginning." 
 
 Therfi are two great infinites, — the infinite in space 
 and the infinite in time. It were well, surely, to be hum- 
 ble enough to acknowledge it accordant to all analogy, 
 that as He who inhabits eternity has filled the one limit- 
 less void — that of space — with world upon world and 
 system upon system, far beyond the reach of human ken, 
 He should also have wrought in the other limitless world 
 — that of time — for age after age, and period after period, 
 far beyond the reach of human conception.
 
 LECTURE FOURTH. 
 
 Tlie Continuity of Existence twice broken in Geological History — The Thre« 
 great Geological Divisions representative of three independent Orders of Ex< 
 istences — Origin of the Wealden in England — Its great Depth and Higlj 
 Antiquity — The question whether the Weald Formation belongs to the Creta^ 
 ceous or the Oolitic System determined in favor of the latter by its Position in 
 Scotland — Its Organisms, consisting of both Salt and Fresh Water Animals, 
 indicative of its Fluviatile Origin, but in proximity to the Ocean — The Out- 
 liers of the Weald in Morayshire — Their Organisms — The Sabbath- Stone of the 
 Northumberland Coal Pits — Origin of its Name — The Framework of Scot- 
 land — The Conditions under which it may have been formed — The Lias and 
 the Oolite produced by the last great Upheaval of its Northern Mountains — • 
 The Line of Elevation of the Lowland Counties — Localities of the Oolitic 
 Deposits of Scotland — Its Flora and Fauna — History of one of its Pine 
 Trees — Its Animal Organisms — A Walk into the Wilds of the Oolite Hills ol 
 Sutherland. 
 
 The mystic thread, Avith its three strnntis of blacky 
 white, and gray, spun by the sybil in " Guy Mannering," 
 formed, she said, a "full hank, but not a haill ane:" the 
 lengthened tale of years which it symbolized " was thrice 
 broken and thrice to asp," I have sometimes thought of 
 that wondei-fully mingled and variously colored thread of 
 existence which descends from the earliest periods known 
 to the geologist down to our own times, as not unaptly 
 represented by that produced on this occasion from the 
 spindle of the gipsy. We find, in its general tissue, species 
 interlaced Avith and laying hold of species, as, in the thread, 
 fibre is interlaced with and lays hold of fibre ; and as by 
 this arrangement the fibres, though not themselves continu- 
 ous, but of very limited length, form a continuous cord, so
 
 LECTURES ON GEOLOGY. 169 
 
 species of limited duration, that at certain parts in the 
 course of time began to be, and at certain other parts 
 became extinct, form throughout immensely extended 
 periods a continuous cord of existence. New species had 
 come into being ere the old ones dropped away and disap- 
 peared ; and there occurred for long ages no break or 
 hiatus in the course, just as in the human family there 
 occurs no abrupt break or hiatus, from the circimistance 
 that new generations come upon the stage ere the old 
 ones make their final exit. But in the geological thread, 
 as in that of the sybil, the continuity is tioice abruptly 
 broken, and the thread itself divided, in consequence, into 
 three parts. It is continuous from the present time up to 
 the commencement of the Tertiary period; and then so 
 abrupt a break occurs, that, with the exception of the 
 microscopic diatomacea^, to which I last evening referred, 
 and of one shell and one coral, not a single species crosses 
 the gap. On its farther or remoter side, however, where 
 the Secondary division closes, the intermingling of species 
 again begins, and runs on till the commencement of this 
 great Secondary division ; and then, just where the Pa- 
 laeozoic division closes, we find another abrupt break, 
 crossed, if crossed at all, — for there still exists some doubt 
 on the subject, — by but two species of plant.^ And then, 
 from the farther side of this second gap the thread of 
 being continues unbroken, until Ave find it terminating 
 with the first beginnings of life upon our planet. Why 
 these strange gaps should occur, — why the long descend- 
 ing cord of organic existence should be thus mysteriously 
 broken in three, — we know not yet, and never may ; but, 
 
 ' For a reference to tlie research of the last two years, which has been 
 busily at work upon this precise epoch, see Preface. 
 
 15
 
 170 LECTURES ON GEOLOGY. 
 
 like the division into books and chapters of some great 
 work on natural history, such as that of Cuvier or Buffon, 
 it serves to break up the whole according to an intelligible 
 plan, the scheme of which we may, in part at least, aspii'e 
 to comprehend. The three great divisions of the geol- 
 ogist, — Tertiary, Secondary, and Paljeozoic, — of which 
 these two chasms, with beginnings of life on the one hand, 
 and the present state of things on the other, form the 
 terminal limits, — represent each, if I may so express my- 
 self, an indeijendent dynasty or emi^ire. Under certain 
 qualifications, to which I shall afterwards refer, the Ter- 
 tiary division represents the dynasty of the mammal ; the 
 Secondary division the dynasty of the reptile; and the 
 Palaeozoic division the dynasty of the fish. Each of the 
 divisions, too, has a special type or characteristic fashion 
 of its own ; so that the aspect of its existences differs as 
 much in the grouj) from the aspect of the existences of 
 each of the others, as if they had been groups belonging 
 to different planets. The vegetable and animal organisms 
 of the planet Venus may not differ more from those of the 
 planet Mars, or those of Mars from the organisms of the 
 planet Jupiter, than the existences of the Tertiary division 
 differ from those of the Secondary one, or those of the Sec- 
 ondary one from the existences of the Palaeozoic division. 
 Beneath the two great divisions of the Cretaceous sys- 
 tem, and consequently of more ancient date, there occurs 
 in the sister kingdom an important series of beds, chiefly 
 of lacustrine or fluviatile origin, known as the Wealden. 
 Before the submergence of what are now the south-eastern 
 parts of England, first beneath the comparatively shallow 
 sea of the Greensand, and then beneath the profounder 
 depths of the ocean of the Chalk, a mighty river, the drain- 
 age of some unknown continent, seems to have flowed for
 
 LECTURES ON GEOLOGY. 171 
 
 many ages along these parts of Kent, Surrey, and Sussex, 
 known as the Valley of the Weald. The banks of this 
 old nameless river were covered with forests of coniferous 
 trees of the Pine and Araucarian families, with cycadeae 
 and ferns, and were haunted by gigantic reptiles, herbiv- 
 orous and carnivorous, some of which rivalled in bulk the 
 mammoth and the elephant; its waters were inhabited by 
 amphibire of the same great class, chiefly crocodiles and 
 chelonians of extinct species and type; by numerous fishes, 
 too, of the old ganoid order; and by shells whose families, 
 and even genera, still exist in our pools and rivers, though 
 the species be all gone. Winged reptiles, too, occasionally 
 flitted amid its woods, or sped over its broad bosom ; and 
 insects of the same fomily as that to which our dragon flies 
 belong spent the first two stages of their existence at the 
 bottom of its pools and shallows, and the terminal one in 
 darting over it on their wings of delicate gauze in quest of 
 their prey. It is stated by Dr. Mantell, our highest author- 
 ity on the subject of the Weald, that the delta of this 
 great river is about two thousand feet in thickness, — a 
 thickness which quadruples that of the delta of the Mis- 
 sissippi. There can be little doubt that the American 
 "Father of Waters" is a very ancient river; and yet it 
 would seem that this river of the Wealden, which has now 
 existed for myriads of ages in but its fossilized remains, 
 hidden under the Wolds of Surrey and Kent, — this old 
 river, which flowed over where the ocean of the Oolite 
 once had been, and in turn gave place and was overflowed 
 by the ocean of the Chalk, — continued to roll its down- 
 ward waters amid forests as dense and as thickly inhabited 
 as those of the great American valley, during a period per- 
 haps four times as extended. 
 
 Compared with the English formation of the Weald,
 
 172 LECTURES ON GEOLOGY. 
 
 which extends ovei- a wide, and what was at one time a 
 very rude district, our beds of the Scotch Wealden are but 
 of little depth, and limited extent. And yet they serve to 
 throw a not vmimportant light on the true character and 
 place of the formation. It occurs in England, as I have 
 said, between two great marine systems, — the Cretaceous 
 and the Oolitic ; and the question has arisen, to which of 
 these systems does it belong? Now, our Scotch beds of 
 the Weald determine the question. They make their ap- 
 pearance, not at the top of Oolitic deposits, as in England, 
 but intercalated throughout the system, — occurring in the 
 Isle of Skye, where they were first detected many years 
 ago by Sir Roderick Murchison, immediately under the 
 Oxford clay, a bed of the Middle Oolite ; and at Brora, 
 where they were first detected a few twelvemonths since 
 by Mr. Robertson of Elgin, in pretty nearly the same me- 
 dial position, and where what is known as the great Oolite 
 occurs. Three years ago I had the pleasure of detecting 
 a bed of the same lacustrine or estuary character, and 
 bearing many of the characteristic marks of the Weald, 
 greatly lower still, — lower, indeed, than any fresh-water 
 deposit of the Secondary division in Britain. I found it 
 occurring not forty yards over the bottom of the Lias, — 
 the formation which constitutes the base of the Oolitic 
 system. In Morayshii-e the Weald occurs in the form 
 of outliers, that rise, as at Linksfield, in the immediate 
 neighborhood of Elgin, into low swelling hills, resting on 
 the Old Red Sandstone of the district, and so tlioroughly 
 insulated from every other rock of the same age, that they 
 have reminded me of detached hillocks of debris and ashes 
 shot down on the surface of some ancient moor by some 
 painstaking farmei-, who had contemplated bringing the 
 waste under subjection to the plough. But though value-
 
 LECTURES ON GEOLOGY. 173 
 
 less, from their detached character, for determining the 
 place of the formation, they serve better than the inter- 
 calated beds of Ross, Skye, and Sutherland, to establish 
 by their animal remains the palseontological identity of the 
 Scotch with the English Wealden. 
 
 Rather more than twelve years ago, the late Dr. John 
 Malcolmson, of Madras, — a zealous and accomplished ge- 
 ologist, too early lost to science and his friends, — brought 
 with him, when on a visit to the Continent, several speci- 
 mens of ichthyic remains from a Morayshire deposit, and 
 submitted them to Agassiz. "Permit me," said the natur- 
 alist, " to find out for myself the formation to which they 
 belong." He passed hand and eye over tooth and spine, 
 plate and bone, and at length set his finger on a single 
 scale of rhomboidal form and brightly enamelled surface. 
 "Some of these teeth," he said, " belong to the genus Hybo- 
 dus, but the species are new, and the genus itself has a wide 
 range. Here, however, is something more detenninate. 
 This scale belongs to the Lepidotus minor, or ichthyolite 
 of the Weald, and one of the most characteristic fishes 
 of the great fresh-water formation of Sui'rey and Kent." 
 The fossils on which the distinguished ichthyologist thus 
 promptly, and, as it proved, correctly decided, had been 
 collected by Mr. Malcolmson fi*om the Wealden outlier 
 at Linksfield ; and the ichthyolite which he so specially 
 singled out — the Lepidotus — seems to have been a 
 fi-esh-water fish of the nearly extinct ganoid order, and 
 more nearly akin to the Lepidosteus of the North Ameri- 
 can rivers and lakes than to any other fish that now exists. 
 By much the greater number of its contemporaries in the 
 deposit also belonged to lakes and rivers. Some of the 
 limestone slabs are thickly covered over by fresh-water 
 shells, of types very much akin to those which still occur 
 
 15*
 
 174 LECTURES ON GEOLOGY. 
 
 in our pools and ditches, such as Planorbis and Paludina. 
 It presents also beds of a fresh-Avater mussel akin to a 
 mussel of the English Weald, — 3Iytihis Lyellii ; and it 
 so abounds in the remains of those minute, one-eyed crus- 
 taceans known as the Cyprides, that the vast numbers of 
 their egg-shaped shelly cases give to some of the beds a 
 structure resembling the roe of a fish. It contains, too, 
 bones of a species of tortoise, and several other decidedly 
 fresh-water remains ; while another class of its organisms 
 serve to show that it w\as occasionally visited by denizens 
 of the sea. It has furnished specimens of bones and teeth 
 of Plesiosaurus, — a marine reptile ; and some of the upper 
 beds contain a small oyster ; while a class of its remains, 
 — the teeth and huge dorsal spines of Hybodonts, an ex- 
 tinct family of sharks, — though they may have been fitted 
 to sustain life in brackish water, seem to indicate rather a 
 sea than a lacustrine or river habitat. The deposit took 
 place in all probability in the upper reaches of an estuary 
 opei-ated upon by the tides, and at one time fresh and at 
 another brackish, and where, in a certain debatable tract, 
 the fishes, reptiles, and shells of the river met and mingled 
 with the fishes, reptiles, and shells of the sea. I may men- 
 tion, that in the immediate neighborhood of the fresh-water 
 or "Weald beds, intercalated, as in Ross and Sutherland, 
 with the marine deposits of the Lias or Oolite, there al- 
 ways occur beds of a species of shell which, though it ex- 
 hibits internally a peculiar structure of hinge, unlike any 
 other known to the conchologist, bears externally very 
 much the appearance of a mytilus or mussel. It seems to 
 have lived in brackish water, and to have marked a tran- 
 sition stage between the marine and lacustrine, — the salt 
 and the fresh ; for immediately under or over it, as the 
 case occurs, the explorer is ever sure to find productions of
 
 LECTURES ON GEOLOGY. 175 
 
 the land or of fresh water, — lake or river shells, such as 
 cyclas or paludina, or portions of terresti-ial plants, and oc- 
 casionally of fresh- water tortoises. This transition shell is 
 known as the Pern a. These notices you will, I am afraid, 
 deem tediously minute; but they indulge us with at least 
 a glimpse of a portion of what is now our country during 
 an immensely extended period, of which no other record 
 exists. Where some nameless river enters the sea, we de- 
 termine, as through a thick fog, which conceals the line of 
 banks on either hand, that the waters swarm with life, rep- 
 tilian and ichthyic : the glossy scales of the river Lepidotus 
 gleam bright through the depths ; while the shark-like 
 Hyhodus from the distant ocean shows above the surface 
 his long dorsal fin, armed with its thorny spine ; and over 
 beds of shells of mingled character, a carnivorous fresh, 
 water tortoise, akin to the fierce Trionyx of the southern 
 parts of North America, meets with the scarce more form- 
 idable sea-bora Plesiosaurus. 
 
 In these Morayshire outliers of the Weald we first find 
 in situ in our country (for we need scarce take into account 
 the Tertiary beds of Mull), fossiliferous deposits that have 
 been converted into solid rock ; and certainly the appear- 
 ance of some of the sections is such as to awaken curiosity. 
 In the section of Linksfield, in the neighborhood of Elgin, 
 though the thickness of the deposit does not exceed forty 
 feet, there occur nimaerous alternations of argillaceous and 
 calcareous beds, differing from each other in color and 
 quality, and not unfrequently in their fossils also ; and each 
 of which evidently represents a state of things which ob- 
 tained during the period of their deposition, distinct from 
 the preceding and succeeding states.^ Strata of gray, 
 
 1 Fielding, in his " Voyai^e to Lisbon (1754)," gives an account of an 
 inaccessible bank of mud which stretcb'jd at tow water >>ctwe«n tb»i shore
 
 176 LECTURES ON GEOLOGY. 
 
 green, blue, and almost black clays, alternate with beds of 
 light green, light brown, gray, and almost black limestones; 
 and such is the effect, when a first section is opened in the 
 deposit, as sometimes happens to facilitate the working of 
 a limestone quarry below, that one is reminded, by the 
 variety and peculiar tone of the colors, of the inlaid work 
 of an old-fashioned cabinet made of the tinted woods which 
 were in such common use about two centuries ago. Some 
 of these bands seem, from their contents, to be of fresh 
 water ; some of marine origin ; one bed nearly four feet in 
 thickness is composed almost exclusively of the shelly 
 coverings of a minute crustacean, — Cypris glohosa, — not 
 half the size of a small pin-head; one is strewed over with 
 the teeth of sharks ; one with the plates and scales of 
 ganoidal fishes ; in one a small mussel is exceedingly 
 abundant ; another contains the shells of Planorbis and 
 Paludina ; in this layer we find a small oyster, which must 
 have lived in the sea ; in that, a Cyclas, the inhabitant of 
 a lake ; here the plates of a river tortoise ; there the bones 
 of the marine Plesiosaur. Of all the many-colored strata 
 of which the deposit consists, there is not one which does 
 not speak of that law of change of which the poet, as if in 
 anticipation of the discoveries of modern science, sings sq 
 philosophically and well : 
 
 Of chance or change, oh ! let not man complain, 
 Else shall he never, never cease to wail ; 
 
 at Ryde and the sea. " Between the shore and the sea," he says, " there 
 is at low water an impassable gulf of deep mud, which can neither be 
 traversed by walkinj^ or swimmiiif?, so that for near one-half of the twenty- 
 four hours Ryde is inaccessible by friend or foe." The same tract now is 
 occupied Ijy an exi)aTise of firm white sand, which forms excellent bathing 
 ground; but immediately under, at the depth of from eighteen inches to 
 two feet, the mud of Fielding's days is found occurring as a dark-colored 
 impalpable silt.
 
 LECTURES ON GEOLOGY. 177 
 
 For from the imperial dome, to where the swain 
 Rears the lone cottaijc in the silent dale, 
 All feel the assault of Fortune's fickle t;alc; 
 Art, empii-e, earth itself, to change are doomed: 
 Earthquakes have raised to heaven the humble vale, 
 And gulfs the mountain's mighty mass entombed; 
 And where the Atlantic rolls, Avide continents have bloomed. 
 
 Regarded, too, as the record of, if I may so express my- 
 self, a party-colored time, these party-colored layers are of 
 no little interest. There forms in the recesses of the 
 Northumbrian coal-pits a party-colored clay, consisting of 
 gray and Llack layers, which, from a certain peculiarity to 
 which I shall immediately advert, bears the name of Sab- 
 bath-stone. The springs which ooze into the pits are 
 charged with a fine impalpable pipe-clay, which they 
 deposit in the pools and waters of the deserted workings, 
 and which is of a ])ale gray color approaching to white. 
 When the miners are at work, however, a light black dust, 
 struck by tlieir tools from the coal, and carried by cur- 
 rents of air into the recesses of the mine, is deposited 
 along with it ; and, in consequence, each day's Avork is 
 marked by a thin black layer in the mass, while each 
 night during which there is a cessation of labor, is repre- 
 sented by a pale layer, which exhibits the color natural to 
 the clay. And when a cross section of the substance 
 thus deposited comes to be made, every week of regular 
 employment is found to be represented by a group of six 
 black streaks closely lined off on a pale ground, and each 
 Sabbath by a broad pale streak interposed between each 
 group, — exactly such a space, in short, as a clerk, in keep- 
 ing tally, would leave between his fogots of strokes. In 
 this curious record a holiday takes its place among the 
 "working days, like a second Sabbath. "How comes this 
 week to have two Sabbaths?" inquired a gentleman to
 
 178 LECTURES ON GEOLOGY. 
 
 whom a specimen was shown at one of the pits. "That 
 blank Friday," replied the foreman, "was the day of the 
 races." — " And what," said the visitor, " means tliis large 
 empty space, a full fortnight in breadth and more?" — "O, 
 that space," rejoined the foreman, "shows the time of the 
 strike for wages : the men stood out for three weeks, and 
 then gave in." In fine, the Sabbath-stone of the Nor- 
 thumbrian mines is a sort of geologic register of the work 
 done in them, — a sort of natural tally, in which the sedi- 
 mentary agent keeps the chalk, and which tells when the 
 miners labor and when they rest, and whether they keep 
 their Sabbaths intact or encroach upon them. One would 
 scarce expect to find of transactions so humble a record in 
 the heart of a stone; but it may serve to show how very 
 curious that narrative might be, could we but read it 
 aright) which lies couched in the party-colored layers of 
 the Morayshire Wealden. All its many beds, green, 
 black, and gray, argillaceous and calcareous, record the 
 workings of nature, with her alternations of repose, in a 
 time of freqiient vicissitude, and amid its annals of chem- 
 ical and mechanical change embody in many an episo- 
 dical little passage its exhibitions of anatomical structure 
 and its anecdotes of animal life. 
 
 Before jJ^ssing on to the Oolite, as developed in Scot- 
 land, or rather to our Scotch deposits of the marine 
 Oolite, — for what we call our Wealden is, as I have 
 shown, merely an estuary or lacustrine Oolite, — let me 
 solicit your attention to a few points illustrative of what 
 may be termed the framework of our country. There are 
 two sets of conditions under which land may arise from 
 the ocean. Its hills and plateaus may be formed by the 
 subterranean forces violently thrusting them up, like vast 
 wedges, through the general crust of the earth, and high
 
 LECTURES ON GEOLOGY. 179 
 
 over the ocean level ; or it may be brought up to the light 
 and air en 7nasse by a general elevation over wide areas 
 of the unbroken crust itself; or land may again sink 
 under these two sets of conditions : it may sink in conse- 
 quence of a breaking up and prostration of its framework 
 to the average level of the crust, — of a striking back, 
 if I may so speak, of the protruded wedges; or it may 
 sink in consequence of a general depression over a wide 
 area of the portion of the crust on which its framework is 
 erected. Thus Scotland might disajjpear under the waves, 
 either by some violent earthquake convulsion that would 
 strike down its hills and table-lands to the general level 
 cJf the earth's crust, and of consequence wholly destroy ifS* 
 contour; or it might disappear through a gentle sinking 
 of the area that it occupies, which would leave its general 
 contour unchanged. Were there a depression to take place 
 where it now rises, of T5iit one foot in five hundred over 
 an area a thousand miles square, its highest mountain 
 summits would be buried beneath the sea, and yet the 
 contour of the submerged land would remain almost iden- 
 tically what it is, — its hills would retain the same relative 
 elevation over its valleys, and its higher table-lands over 
 its lower plains. Now, in the later ages of its history, — 
 in those ages, for instance, in which the ice-laden ocean of 
 the boulder-clay rose high along its hill-sides, and it ex- 
 isted as a wintry archipelago of islands, — there seems to 
 have taken place scarce any change in its framework : the 
 depressions through which it sank, and the elevations 
 through which it rose, seem to have been depressions 
 and elevations of area; and, whether under or over the 
 waves, it continued to retain its general contour. The 
 last great change Avhich affected its framework, and gave 
 to it a different profile in relation to the general surface of
 
 180 LECTURES ON GEOLOGY. 
 
 the globe from that which it had borne in the eai'Her ages, 
 — the change which thrust up its latest-born lines of 
 mountains like wedges through the earth's crust, — was 
 a change which took place a little posterior to that period 
 of its histoiy at which I am now arrived. We find that 
 its last lines of hills disturbed and bore up with them 
 deposits of the Lias and of the Oolite, but of no later 
 formations. The gigantic Ben Nevis and his Anakim 
 brethren of the same group were raising their heads 
 and shoulders through the earth's crust, to form the future 
 landmarks of our country, shortly after the period when 
 the river Lepidoids of the Wealden were disporting in 
 the same brackish tract with the Hybodont sharks of its 
 seas, and its fresh-water Chelonians and marine Plesiosauri 
 met and intermingled in the same neutral rocks of es- 
 tuary. 
 
 The last great paroxysm of upheaval among our Scot- 
 tish mountains seems to have operated in lines that trav- 
 ersed the country diagonally from nearly south-west by 
 south to north-east by north, — the line indicated by that 
 of the great Caledonian Valley. We find a northern 
 district of considerable extent ploughed in this direction 
 by the great parallel glens traversed by the Spey, the 
 Findhorn, the Nairn, and tlie Ness. The northern shore 
 of the Moray Frith, too, with that remarkable line of hills 
 which includes the Sntors of Cromarty, pertains to this 
 system, as also the higher mountain range which rises 
 along the coast of Sutherland, and to which the Ord Hill 
 of Caithness belongs. These lines of hills, wherever they 
 have come in contact — as along the shores of the Moray 
 Frith — witli beds of the Lias and Oolite, have disturbed 
 and tilted up, at a steep angle, their edges. The hill of 
 Eathie, in tlie neighborhood of Cromaity, — a hill of the
 
 LECTURES ON GEOLOGY. 181 
 
 series in which the two Sutors occur, — has at one place 
 borne up the Lower Lias on its flanks at an angle of eighty; 
 and among the rocks of the Northern Sutor there is a tall 
 precipice of the Old Red Sandstone, with an uptilted 
 deposit of the Lias at its base, whose abrupt, dizzy front, 
 once the haunt of the eagle, and still that of the blue 
 hawk, was evidently, ere the elevation of the series, part 
 of the horizontal platform on which the first Liassic stra- 
 tum had been deposited. What was a flat submarine bot- 
 tom then, is a steep ivy-mantled precijnce now. Across 
 the long deep valleys and mountain ridges of this last line 
 of upheaval in Scotland, — the line to which Ben Nevis, 
 Milfourveny, and the Ord Hill of Caithness belong, and 
 whose period of elevation a high Continental authority, 
 Elie de Beaumont, regards as identical with that of the 
 Mont Pilas and Cote d'Or of France, — we find a greatly 
 less continuous, because more interrupted and broken, set of 
 ridges, running in a nearly westerly direction. The friths 
 of Dornoch, Cromarty, and Beauly, with all the bays 
 of Munlochy and Urquhart, Loch Oich and Loch Eil, 
 which all strike westwards across the country from off the 
 great diagonal trench of the Caledonian Valley, indicate 
 the direction of this second and eai-lier line of upheaval. 
 I say earlier line. The hills of the diagonal Ben Nevis 
 line disturbed and broke up the Oolite, whereas the hills 
 of the transverse, or, as I may term it, Ben Weavis line, 
 disturbed and bore up with them nothing more modem 
 than the Old Red Sandstone. I have described the 
 northern part of the kingdom as consisting of a great 
 Primary nucleus, surroimded by strata, more or less 
 broken, of Old Red Sandstone, Lias, and Oolite.^ Let 
 
 1 To which is to be now added Silurian. 
 16
 
 182 LECTURES ON" GEOLOGY. 
 
 US now further conceive of that nucleus as a stony field, 
 that had been first ploughed across and fretted into deep 
 furrows and steep mountainous ridges, and then in an after 
 period ploughed diagonally, so as partially to efface the 
 former ploughing, so that only in the direction of the last 
 ploughing do the ridges and furrows remain tolerably 
 entire, — let us, I say, conceive of such a ploughed field, 
 and we will have a tolerably adequate conception, so far 
 as it goes, of the framewoi-k of at least the northern 
 portion of Scotland. In the southern part of the king- 
 dom there is yet another line of elevation exhibited, 
 whose direction from nearly north-east to south-west we 
 find indicated by the nearly parallel lines in which the 
 greater formations of the Lowland counties, from the clay- 
 states that flank the Grampians, to the Grauwackes of the 
 border districts, sweep across the country. I fear that the 
 homely illustrations which I have to employ in rendering 
 my subject com])rehensible, — such as wedges struck up- 
 wards from below, — a field first ploughed acx'oss and then 
 diagonally, — may have the effect of so reducing ray sub- 
 ject in your minds into a mere model, that, through the 
 necessary reduction, more may be lost in expansiveness of 
 feeling than gained by any substitution of clearness of 
 view. There can be little doubt that in the conceptions 
 of mind, as in the collocations of matter, the portable 
 means the small; and that Goethe exercised his wonted 
 shrewdness in remarking, that when the ancients spoke 
 of the unmeasurable earth and the illimitable sea, it was 
 with a profounder feeling than any now exercised by the 
 geographei- in a time when every school-girl can tell that 
 the world is round. You will, however, remember, that 
 though my illustrations are small, my subject is large; and 
 Buch of my audience as have sailed over the profound
 
 LECTURES ON GEOLOGY. 183 
 
 depths of Loch Ness, — depths greatly raore profound than 
 tliose of the German Ocean beyond, — and seen those 
 lines of russet mountains, so often capped with cloud, and 
 so often, even at midsummer, streaked with snow, — that 
 rise on either hand, and that inclose from sea to sea that 
 mighty trench which the old unsophisticated Highlander 
 learned to distinguish as the great Glen of Albyn, — when 
 they call up to memory the noble features of the scene, — 
 the long retiring vista on either hand, purple in the far 
 distance, and remember that that vast rectilinear hollow 
 forms but one of the plough furrows of my illustration, — 
 they will see that that with which I am in reality deal- 
 ing is the sublime of nature, and that even the details 
 of my subject, rightly appreciated, are not suited to loAver 
 our conceptions of the Avonderful Avorkings of old of Him 
 ■who, by processes which science is but now aspiring to 
 comprehend, "gathered the waters together into one place, 
 1,hat the dry land might appear," and laid the deep-seated 
 ^undation of the mighty hills. 
 
 Let us now pass to the Oolite proper, and its base the 
 Lias, as we find them developed in Scotland. They form 
 but a comparatively small portion of the surface of the 
 country, — not much more, it has been estimated, than 
 *iixty square miles; nor can I refer definitely to any 
 marked peculiarity of scenery in the districts in which 
 they occur. The Oolites of Sutherland extend westwards 
 and southwards from the Ord Hill of Caithness to the 
 village of Golspie, a distance of about sixteen miles; and 
 form, under the rugged line of hills against whose flanks 
 they recline, a green narrow strip of low country, that, 
 where not too deeply covered up by debris of the Primary 
 rocks, trans|)orted from the interior during the Pleistocene 
 period, is, for its extent, of great agricultural value, and
 
 184 LECTURES ON GEOLOGY. 
 
 bears on its cultured surface the rich fields and extensive 
 woods of Dunrobhi, tlie stately castle of the old earls of 
 Sutherland. Further to the west and south, along the 
 eastern shores of Cromarty and Ross, detached patclies of 
 the Lias occur, as at Shandwick, at the Noithern Sutor 
 of Cromarty, at the Southern Sutor, and at the Hill of 
 Eathie, — each patch occurring directly opposite, and lean- 
 ing against, one of the upheaved hills, which, as I have 
 already said, were undoubtedly the agents in raising and 
 bringing it to the surface. The Lias and Oolite also ap- 
 pear on the southern side of the Moray Frith, in the 
 counties of Moray and BaniF, but merely as outliers of 
 very limited extent, and sorely broken up or ground down 
 by the denuding Pleistocene agencies. On the western 
 coast of Scotland the Lias may be seen on the mainland 
 at Applecross, and on the sides of Loch Aline, opposite 
 the Sound of Mull ; while in the inner Hebrides, it forms, 
 with the Oolite, though greatly overflown by trap, the 
 base of the larger part of the island of Mull, of two of 
 the Small Isles, Eigg and Muck, of Raza and Scalpa, and 
 of large tracts of the eastern and northern half of Skye. 
 At Broadford, in the latter island, the Lias forms the 
 whole of the rich level islet of Pabba, Avhich, lying as 
 at anchor in its quiet bay, reminds one, from its prevail- 
 ing color and form, of one of the low, green steamboats 
 of the Clyde. Opposite Pabba, the Liassic deposit sweeps 
 across the mainland of Skye from sea to sea, along a flat 
 valley some two or three miles wide ; but Avhile the mi- 
 nute Liassic islet resembles, from the softness of its out- 
 line, an islet of England set down in a hill-enclosed bay 
 of the Scottish Highlands, there is nothing English in the 
 scenic character of the Liassic valley. It is a brown and 
 sombre expanse of marsh and mooi*, studded by blue,
 
 LECTURES ON GEOLOGY. 185 
 
 dreary lochaiis, interesting, however, to the botanist, as 
 the habitats of the rare Eriocaulon septangulare. The 
 waste is haunted, too, say the Highlanders, by Ludag, a 
 malignant goblin, not more known elsewhere in Europe 
 than the rare plant that in the last age used to be seen 
 at dusk hopping with immense hops on its one leg, — for, 
 unlike every other denizen of the supernatural world, it is 
 not furnished with two, — and that, enveloped in rags, 
 and with fierce misery in its hollow eye, has dealt heavy 
 blows, it is said, on the cheeks of benighted travellers. 
 Certainly a more appropriate spectre could scarce be sum- 
 moned to walk at nights over the entombed, remains of 
 the old monsters of the Lias than one-legged Ludag, the 
 goblin of the wastes of Broadford. Such, in brie^ is a 
 summary of our Oolitic deposits. They occupy, as I have 
 said, but a small portion of the surface of Scotland ; and, 
 though coal has occasionally been wrought in them, and 
 though they furnish in several localities supplies of lime 
 and of building stone, their economic importance is com- 
 paratively small. But a well-filled volume — the life- 
 long work of some laborious chronicler — may have no 
 economic importance in the lower and humbler sense, 
 and may yet form a valuable record of bygone transac- 
 tions and events suited to delight and instruct throughout 
 all generations. And it is thus with the Oolitic deposits 
 of Scotland. Their innumerable strata, closely wi-itten 
 " within and without " in a language in which every 
 character is an organism, form the leaves of a record in 
 which many of the marvellous existences that flourished 
 during what are geologically the middle ages of our coun- 
 try's history are Avell and wonderfully preserved. Instead 
 of dissipating your attention by describing at length the 
 fossils of its various deposits, I shall attempt giving you 
 
 16*
 
 186 LECTURES ON GEOLOGY. 
 
 a general idea of the whole under the ordinary division 
 of animal and vegetable, as they have come to my knowl- 
 edge during the researches of at least thirty years. 
 
 In one of its features Oolitic flora of what is now Scot- 
 land must have resembled its flora in the present, or rather 
 in the past age, ere our native pine-woods had yielded to 
 the axe. Trees of the fir or pine division of the Coniferae, 
 many of them of slow growth and large size, must have 
 formed huge forests in a province of the land of the Oolite 
 which extended from what is now the island of Mull to 
 the Ord Hill of Caithness. The Scuir of Eigg, a subaerial 
 mole of columnar pitchstone, four hundred feet in height, 
 and perched on the ridge of a tall hill, rests on the remains 
 of a prostrated forest, as some of our submarine moles rest 
 on foundations of piles. And of this forest all the trees 
 seem to have consisted of one species, — a conifer of the 
 Oolite now known to the fossil botanist as the JPinites 
 Eiggensis^ or Eigg pine. Branches and portions of the 
 trunks of a similar \}mQ are not unfrequent in the Lias of 
 Eathie and Koss ; and in shale-beds of the Lower Oolite 
 in the neighborhood of Helmsdale there occur in abun- 
 dance fossil trunks and branches, mingled with cones and 
 the narrow spiky leaflets characteristic of the family. I 
 have reckoned in the transverse section of a Helmsdale 
 pine-trunk about two feet in diameter, more than a hun- 
 dred annual rings. And from the rings and roots of some 
 of the others, its contemporaries, I found that curious 
 insight miglit be derived respecting the state and condi- 
 tion of vegetable life in the old Scotch woods of the 
 Oolite. In the first j^lace, the annual rings themselves 
 told me, wlien exposed to transmitted light in the micro- 
 scope, that the winters of that time gave vegetation as 
 decided a check as our winters now. The tender woody
 
 LECTURES UN GEOLOGY. 187 
 
 cells were first dwarfed and thickened in their formation 
 by the strengthening of the autumnal cold, and then for 
 a season they ceased to form altogether. But then the 
 spring came, and over the hard concentric line drawn by 
 the chill hand of winter they began to form themselves 
 anew in full-sized luxuriance ; and thus, year after year, 
 and for century after century, the process went on. Some 
 of these ancient pine-trees grew in rich sheltered hollows, 
 and acquired bulk so rapidly, that they increased their 
 diameter eight and a half inches in twenty years ; others 
 grew so slowly, that they increased their diameter only 
 two and a half inches in forty years. And it is a curious 
 circumstance, that in both those of slower and of more 
 rapid growth we find alternating grouj5s of broader and 
 narrower annual rings, indicating apparently grouj^s of bet- 
 ter and worse seasons. Lord Bacon remarks in one of his 
 Essays, — the Essay on the Vicissitude of Things, — that 
 it was a circumstance first observed in the Low Countries 
 (the provinces of the Netherlands), that there were cer- 
 tain meteorological cycles of seasons — groups of warmer 
 and groups of colder summers, and of more temperate and 
 of less temperate winters — which periodically came round 
 again. And we have seen not very successful attempts 
 made in our own times to measure these cycles, and reduce 
 them to a formula, from which the nature of the coming 
 seasons might be determined beforehand. But there can 
 be little doubt — whatever the cause or the order of their 
 occurrence — that alternations of groups of colder and 
 warmer, better and worse seasons, do occur ; and it seems 
 more than probable that, in obedience to some occult law, 
 as little understood in the present age as when its opera- 
 tions were first detected in the Netherlands, Scotland had 
 in the times of the Oolite, as certainly as now, its alter
 
 188 LECTURES ON GEOLOGY. 
 
 nating groups of chill and of genial summers, and of tem- 
 perate and severe winters. And the well-marked rings of 
 its fossil Coniferae remain to attest the fact. We can even 
 determine the kind of soil into which a certain proportion 
 of these ancient pines struck root. It was extremely shal- 
 low in some localities, and lay over a hard bottom. "We 
 find that some of the fossil stumps shot out their roots 
 horizontally immediately as they entered the earth, and 
 sent down no vertical prolongations of the trunk into the 
 subsoil, — an arrangement still common among the roots 
 of trees planted on a shallow stratum of soil resting on a 
 hard bottom. Further, we are still able to ascertain that 
 the hard bottom that underlay the soil in which some of 
 the Oolitic pines of Helmsdale grew was composed of Old 
 Ked flagstone, identical in its mineral composition and 
 organic remains with what is now known as Caithness 
 flag. 
 
 But let us trace the history of a single pine-tree of the 
 Oolite, as indicated by its petrified remains. This gnarled 
 and twisted trunk once anchored its roots amid the cran- 
 nies of a precipice of dark-gray sandstone, that rose over 
 some nameless stream of the Oolite, in what is now the 
 north of Scotland. The rock, which, notwithstanding its 
 dingy color, was a deposit of the Lower Old Red Sand- 
 stone, formed a member of the fish-beds of that system, 
 — beds that were charged then, as now, with numerous 
 fossils, as sti-ange and obsolete in the creation of the Oolite 
 as in tlie creation which at present exists. It was a firm, 
 undestructible stone, covered by a thin, barren soil ; and 
 the twisted rootlets of the pine, rejected and thrown back- 
 wards from its more solid planes, had to penetrate into its 
 narrow fissures for a straitened and mengro subsistence. 
 The tree grew but slowly : in considerably more than half
 
 LECTURES ON GEOLOGY. 189 
 
 a century it had attained to a diameter of little more than 
 ten inches afoot over the soil; and its bent and twisted 
 form gave evidence of the life of hardship to which it was 
 exposed. It was, in truth, a picturesque rag of a tree, that 
 for the first few feet twisted itself round like an overborne 
 wrestler struggling to escape from under his enemy, and 
 then struck out an abrupt angle, and stretched itself like 
 a bent arm over the stream. It must have resembled, on 
 its bald eminence, that pine-tiee of a later time described 
 by Scott, that high above " ash and oak," 
 
 " Cast anchor in the rifted rock, 
 And o'er the giddy chasm hung 
 His shattered trunk, and frequent flung, 
 Where seemed the cliffs to meet on high, 
 His boughs athwart the narrowed sky." 
 
 The seasons passed over it : every opening spring gave its 
 fringe of tenderer green to its spiky foliage, and every 
 returning autumn saw it shed its cones into the stream 
 below. Many a delicate fern sprang up and decayed 
 around its gnarled and fantastic root, single-leaved and 
 simple of form, like the Scolopendria of our caverns and 
 rock recesses, or fretted into many a slim pinnate leaflet, 
 like the minute maiden-hair or the graceful lady-fern. 
 Flying reptiles have perched amid its boughs ; the light- 
 winged dragon-fly has darted on wings of gauze through 
 the openings of its lesser twigs ; the tortoise and the lizard 
 have liybernated during the chills of winter amid the hol- 
 lows of its roots; for many years it formed one of the 
 minor features in a wild picturesque scene, on which hu- 
 man eye never looked ; and at length, touched by decay, 
 its upper branches began to wither and bleach white in 
 the winds of heaven ; when shaken by a sudden hurricane 
 that came roaring adown the ravine, the mass of rock in
 
 190 LECTURES ON GEOLOGY. 
 
 which it had been anchored at once gave way, and, bear- 
 ing fast jammed among its roots a fragment of the mass 
 which Ave still find there, and from which we read a por- 
 tion of its story, it was precipitated into the foaming tor- 
 rent. Dancing on the eddies, or lingering amid the pools, 
 or shooting, arrow-like, adown the rapids, it at length finds 
 its way to the sea ; and after sailing over beds of massive 
 coral, — the ponderous Isastrea and more delicate Tham- 
 7iastrea, — and after disturbing the Enaliosaur and Belem- 
 nite in their deep-green haunts, it sinks, saturated with 
 water, into a bed of arenaceous mud, to make its aj^pear- 
 ance, after long ages, in the world of man, — a marble 
 mummy of the old Oolite forests, — and to be curiously 
 interrogated regarding its character and history. 
 
 The pines of our Scotch Oolite — some of them, as I 
 have shown, or rather as my specimens show, of exceed- 
 ingly slow growth — are suggestive of a temperate, if not 
 severe climate. The family of their contemporaries, how- 
 ever, to which I must next refer as not less characteristic 
 of the flora of this ancient time than the coniferas them- 
 selves, is now to be found in a state of nature in only the 
 warmer regions of the earth, and can be studied in this 
 part of the world in but our conservatories and green- 
 houses. It is known to the botanist as the Cycadaceous 
 family ; and at least two of its genera, Cycas and Zamia, 
 we find well represented in the Oolitic deposits of Scot- 
 land. In the Zamia, a cylindrical, squat, scale-covered 
 pedestal is fringed along its upper edge by a ring of long 
 pinnate leaves, that radiate outwards like the spokes of a 
 wheel from the nave; and, placed on the centre of the 
 pedestal, there is, when the plant is in fruit, a handsome 
 cone. The tout ensemble is as if a pine-apple, with the 
 pot in which it grew, and with its leaves arranged like a
 
 LECTURES ON GEOLOGY. 191 
 
 ruff round its stem, formed altogether but one plant. The 
 Cycas is usually taller than Zamia; the leaves also, of 
 the compound pinnate character, are smaller and more 
 bushy; and it resembles, as a whole, a decapitated jialm, 
 with a coronal of fern bound atop, as if to conceal the 
 mutilation. With these Cycadacae there flourished in the 
 marshes of the period plants of a family still widely spread 
 over the various climatal zones, but which now attain to 
 any considerable size only within the tropics. I refer to 
 the Equisetaceae, or horsetail family, — slim, cone-crowned 
 plants, fi'inged with green verticillate leaves, or branches 
 rather, and which in this country ai'e rarely thicker than a 
 quill, or rarely exceed eighteen inches in height, but which 
 have been found in the intertropical swamps of South 
 America fifteen feet high, and three inches in circumfer- 
 ence at the lower part of the stem. In the Oolite of 
 Scotland, a well-marked, long-extinct species, the Eqidse- 
 tum columnare must have attained, judging from the 
 thickness of the stem, which is sometimes full three inches 
 in diameter, to at least thrice the size of its tropical con- 
 geners. As shown by its remains, which occur in the 
 lignite shales of Brora, it must have been a plant of con- 
 siderable elegance of form, encircled at each joint in some 
 of the specimens by torus-like mouldings grooved cross- 
 wise, traversed in the spaces between by longitudinal 
 markings, delicately punctulated, and gracefully feathered 
 from root to pointed top by its verticillate garlands of 
 spiky leaves. The LycopodiacejB or club-moss family, 
 existing in rather massier and more aboraceous forms than 
 now, though reduced in a greatly more than equal degree 
 from their gigantic congeners ot the Coal Measui-es, were 
 also abundant (as shown by the rocks of Helmsdale) in 
 the Oolitic floi'a of Scotland ; and with these there min-
 
 192 LECTURES ON GEOLOGY. 
 
 gled various genera, consisting of numerous species of 
 well-marked ferns. Ferns, indeed, so far as we yet know, 
 may be regarded as forming the base, and pines the apex, 
 of the terrestrial Oolitic flora; and between these two 
 extremes most of its other productions seem to have 
 ranged. The Cycadacete jDOSsess certain characters which 
 belong to both : they are, if I may so speak, fern-pines, 
 Avith, in some instances, a peculiarity of aspect which 
 seems also to ally them to the palms. Again, the Lyco- 
 l^odiaceae, intermediate between the mosses and the ferns, 
 may be described as fern-mosses, with a peculiarity of 
 aspect in some of the Oolitic species that seems to ally 
 them to the pines. And the Equisetaceae belongs to at 
 least the same sub-class as the ferns, — the Acrogens. 
 The Palmae, as shown by the English deposits, were also 
 present in the Oolitic flora: nor is it probable that a 
 species of vegetation which the old Yorkshire of the 
 Oolite possessed, the old Scotland of the Oolite should 
 have wanted ; though I have not yet succeeded in finding 
 the remains of palms in any of our Scotch deposits. 
 
 The animal productions of our country during this early 
 pei'iod were divided, like those of the present time, into 
 the four great Cuvierian divisions, all of which we still 
 find in a fossil state in our rocks. Corals akin to the trop- 
 ical forms, — some of them of great size, — with star-fishes 
 and sea-eggs, represent the radiata ; a fossil lobster which 
 occurs in the Lias of Cromarty somewhat meagrely repre- 
 sents the articulata. The shelled mollusca we find very 
 largely represented in almost all their classes and families, 
 li'om the high Cephalopods to the low Brachipods ; and in 
 this division the peculiar character of the Oolitic system is 
 more strongly imjsressed than even on its flora. Its corals, 
 though many of tliem of great size, as I have just said,
 
 LECTURES ON GEOLOGY. 193 
 
 and of elegant form, might almost pass for those of the 
 intertropical seas of tlie present day ; nor are its Crustacea 
 and insects, even wliere best preserved, as in the Oolites 
 of England, of a character -widely diiferent from those 
 which still exist. But by much the larger part of its 
 mollusca bear the stamp of a fashion that has perished. 
 It is chiefly, however, in its molluscs of the first class, — 
 the Cephalopods, — creatures of a high standing in their 
 division, and represented in the present day by the nauti- 
 lus and the cuttle-fish, that we recognize in its fullest extent 
 this extinct peculiarity of type and form. Its Brachipods, 
 chiefly terebratulte, not unfrequent in the Sutherland Ooli- 
 tes, and in the Lias of Cromarty and Skye, — its periwin- 
 kles, whelks, avicula?, pinnae, pectens, oysters, and mussels, 
 few of them wanting in any of our Scotch Liassic or Ooli- 
 tic deposits, and many of them very abundant, though all 
 specifically extinct, present us, though with a large admix- 
 ture of strange and exotic forms, with many other forms 
 with which, generically, at least, we are familiar. But 
 among the Cephalopods all is strange and unwonted ; and 
 their vast numbers — greater at this period of the world's 
 history than in any former or any after time — have the 
 effect of imparting their own unfamiliar character to the 
 whole moUuscan group of the Oolite. I need but refer to 
 two families of these, — the Belemnite family and the fam- 
 ily of the Ammonites ; both of them so remarkable, that 
 they attracted in their rocks the notice of the untaught 
 inhabitants of both England and Scotland, and excited 
 their imagination to the point at which myths and fables 
 are produced, long ere Geology existed as a name or was 
 known as a science. The Belemnites are the old thunder- 
 bolts of the north of Scotland, that, in virtue of their sup- 
 posed descent from heaven, were deemed all potent in 
 
 ]7
 
 194 LECTURES ON GEOLOGY. 
 
 certain cases of bewitchment and the Ammonites are 
 those charmed snakes of the mediaeval legend, 
 
 " That each one 
 "Was changed into a coil of stone. 
 When holy Hilda praj'ed." 
 
 The exact affinities of the Belemnite family have formed a 
 subject of controversy of late years among our highest 
 authorities, — men such as Professor Owen taking up one 
 side, and men such as Dr. Mantell the other. But there 
 can be little doubt that it more nearly approached to our 
 existing cuttle-fishes than to any other living animals; 
 while there is no question that its contemporary the Am- 
 monite is now most nearly represented, though of course 
 only approximately, by the nautilus. Tlie Belemnite ex- 
 isted in some of its species throughout all the formations 
 of the great Secondary division, but neither during those 
 of the Palaeozoic nor yet of the Tertiary divisions ; the 
 Ammonite, on the other hand, though in an extreme and 
 aberrant form, preceded it by several formations, but be- 
 came extinct at the same time, — neither Ammonite nor 
 Belemnite outliving the depo^tion of the Chalk. 
 
 The first great division of the animal kingdom, the 
 vertebrata, was represented in Scotland during the Oolitic 
 period by fishes and reptiles. Its fishes seem to have been 
 restricted to two orders, — that placoid order to which the 
 existing sharks belong, and that ganoid order, now well- 
 nigh worn out in creation, to which the Lepidosteus of 
 the North American lakes and rivers belongs, and to which 
 I incidentally referred in connection with tlie Lepidotus 
 of the WcaM. I Jiavc found in the island of Eigg beds 
 of a limestone composed almost entirely of fossil shells, 
 which were strewed over with the teeth of an extinct
 
 LECTURES ON GEOLOGY. 195 
 
 genus of sharks, the Hybodonts; and I have seen the 
 dorsal spines of the same pUxcoid division occasionally 
 occurring among the Oolites of Sutherland and the Lias- 
 of Eathie. And scales, cerebral plates, and in some in- 
 stances considerable portions of individuals of the ganoidal 
 species, glittering in the enamel to which they owe their 
 name, occur in all the Oolitic deposits of Scotland. Of 
 our Scottish reptiles of the Oolite we have still a good 
 deal to learn. I was fortunate enough in 1844 to find in 
 a deposit of Eigg, and again at Helmsdale in 1849, the 
 remains of several of its more characteristic Enaliosaurs, 
 or bepaddled re2:»tiles of the sea; at Helmsdale I found 
 vertebral joints of the Ichthyosaurus in a conglomerate 
 lower in the Oolite; and in Eigg, in a stratum composed 
 of littoral univalves, vertebral joints, phalanges, and por- 
 tions of the humerus and of the pelvic arch of Plesiosau- 
 rus, together with the limb-bones of crocodileans, and 
 fragments of the carapace of a tortoise. Previous, how- 
 ever, to even the earlier date of my discoveries, the tooth 
 of a Sauiian had been found in the Sutherlandshire Oolite 
 by Mr. (now Sir Roderick) Murchison, and the limb-bone 
 of a Chelonian with a sauroid vertebra, in the outlier of 
 the Morayshire Weald at Linksfield. My collection, how- 
 ever, though still very inadequate in this department, con- 
 tains, in quantity at least, and, I am disposed to think, in 
 variety also, some eight or ten times more of the reptilian 
 remains of Scotland, during the Secondary ages, than all 
 the other collections of the kingdom. They at least serve 
 to demonstrate that the Oolitic period in what is now our 
 country was, as in England and on the Continent, a period 
 of huge and monstrous reptiles, — that the bepaddled 
 Enaliosaurs, the strange reptilian predecessors of the Ce- 
 tacea, haunted our seas in at least two of their generic
 
 193 LECTURES OxNT GEOLOGY. 
 
 forms, — that of the Ichthyosaur and that of the Ple- 
 f<i<.)saur; that our rivers were frequented by formidable 
 crocodiles; and that tortoises of various perished species 
 liA'ed in our lakes and marshes, or, according to their na- 
 tures, disported on the drier grounds. Nor is it probable 
 that the other reptilian monsters of the time, the con- 
 temporaries of these creatures in England, would have 
 been wanting here. We may safely infer that flocks of 
 Pterodactyles — reptiles mounted on bat-like wings, and 
 as wild and monstrous in aspect and jjroportion as roman- 
 cer of the olden time ever feigned — fluttered through 
 the tall pine-forests, or perched on the cycadeae and the 
 ti ee-ferns ; that the colossal Iguanodon and gigantic Hy- 
 Iseosaurus browsed on the succulent equisetacejE of the 
 low meadows; that the minute Amphitherium, an insec- 
 tivorous mammal of the period, lodged among the ferns 
 on the drier grounds, where extinct grasshoppers chirped 
 throughout the long bright summer, and antique coleoptera 
 burrowed in the sand; and that far ofi" at sea there were 
 moments when the sun gleamed bright on the polished 
 sides of the enormous Cetiosaurus, as it rose from the bo1>- 
 tom to breathe. But I must close this part of my subject, 
 — the Scottish flora and fauna of the Oolite, — on which 
 my narrow limits permit me, as you see, to touch at merely 
 a few salient points, — with two brief remarks. First, 
 So rich was its flora, that its remains formed on the east 
 coast of Sutherland a coal, or rather lignite field, so con- 
 siderable that it was wrought for greatly more than a cen- 
 tury, — at one time to such effect, that during the twelve 
 years which intervened between 1814 and 1826, no fewer 
 than seventy thousand tons of coal were extracted from 
 one pit. Second, The strange union which Ave find in the 
 same beds of trees that seem to have laneruished under
 
 ^ LECTURES ON GEOLOGY. 197 
 
 chill and severe skies, witli plants, corals, and shells of a 
 tropical or semi-tropical character, need not be regarded 
 as charged with aught like conflicting evidence resj^ecting 
 the cliuiatal conditions of the time. Climate has its zones 
 marked out as definitely by thousands of feet on our hill- 
 sides as by degrees of latitude on the surface of the globe ; 
 and if the Scotland of the Oolitic period was, as is prob- 
 able, a mountainous country traversed by rivers, jjroduc- 
 tions of an intertropical, and of even a semi-arctic char- 
 acter, may have been not only produced within less than 
 a day's journey of each other, but their remains may have 
 been mingled by land-floods, as Ave find the huge corals of 
 Helmsdale blent with its slow-growing j^ines, among the 
 debris of some littoral bed. The poet's exquisite descrijD- 
 tion of Lebanon suggests, I am disposed to think, the true 
 reading of the enigma : 
 
 " Like a glory the broad sun 
 Hangs over sainted Lebanon, 
 Whose head in wintry grandeur towers, 
 
 And whitens with eternal sleet ; 
 While summer, in a vale of flowers, 
 
 Is sleeping rosy at his feet." 
 
 The mere lists of the botanist and zoologist are in them- 
 selves repulsive and un-ideaed; and yet the existences 
 which their arbitrary signs represent are the vital marvels 
 of creation, — the noble forests, fair shrubs, and delicate 
 flowers, and the many-featured denizens of the animal 
 world, so various in their forms, motions, and colors, and 
 so wondrous in their structure and their instincts. I have 
 been presenting you this evening with little else than a 
 dry list of the Scottish ^productions of the Wealden and 
 Oolitic ages, — a list necessarily imperfect, and all the more 
 unsuggestive from the circumstance that, as myriads of 
 
 17*
 
 198 LECTURES ON GEOLOGY. 
 
 ages had elapsed between the extinction of the races and 
 families which its signs represent, and their first applica- 
 tion as signs, so these signs, in their character as vocables, 
 belong to languages as dead as the organisms themselves. 
 The organisms were dead and buried, and converted into 
 lignite or stone, long ages ere there was language enough 
 in the world to furnish them with names; and now the 
 dead has been employed to designate the dead, — dead 
 languages to designate the remains of dead creations. 
 Could we but see the productions of our country as they 
 once really existed, — could we travel backwards into the 
 vanished past, as we can descend into the strata that con- 
 tain their remains, and walk out into the woods, or along 
 the sea-shores of old Oolitic Scotland, — we should be 
 greeted by a succession of marvels strange beyond even 
 the conceptions of the poet, or at least only equalled by 
 the creations of him, who, in his adventurous song, sent 
 forth the Lady Una to wander over a fairy land of dreary 
 wolds and trackless forests, whose caverns were haunts of 
 dragons and satyrs, and its hills the abodes 
 
 " Of dreadful beasts, that, when they drew to hande, 
 Half-tlying and half-floating, in their haste, 
 
 Did with their largeness measure o'er much lande, 
 And made wide shadow under bulksome waist, 
 
 As mountain doth the valley overcaste; 
 And trailing scaly tails did rear afore 
 
 Bodies all monstrous, horibill, and vaste." 
 
 Let us, however, ere we part for the evening, adventure a 
 short walk into the wilds of the Oolitic, in that portion of 
 space now occupied on the surface of the globe by the 
 north-eastern hills of Sutherland, where they abut on the 
 precipitous Ord. 
 
 We stand on an elevated wood-covered ridge, that on
 
 LECTURES ON GEOLOGY. 199 
 
 the one hand overlooks the blue sea, and descends on the 
 otlier towards a broad river, beyond which there spreads a 
 wide expanse of a mountainous, forest-covered country. 
 The higher and more distant hills are dark with pines; 
 and, save that the sun, already low in the sky, is flinging 
 athwart them his yellow light and gilding, high over 
 shaded dells and the deeper valleys, clifl^ and copse, and 
 bai'e mossy summit, the general coloring of the background 
 would be blue and cold. But the ray falls bright and 
 Avarm on the rich vegetation around us, — tree-ferns, and 
 tall club-mosses, and graceful palms, and the strangely 
 proportioned cycadace®, whose leaves seem fronds of the 
 bracken fixed upon decapitated stumps; and along the 
 banks of the river we see tall, intensely green hedges of 
 the feathered equisetaceae. Brown cones and withered 
 spiky leaves strew the ground; and scarce a hundred 
 yards away there is a noble Araucarian, that raises, sphere- 
 like, its proud head more than a hundred feet over its 
 fellows, and whose trunk, bedewed with odoriferous bal- 
 sam, glistens to the sun. The calm stillness of the air 
 makes itself faintly audible in the drowsy hum of insects ; 
 there is a gorgeous light-poised dragon-fly darting hither 
 and thither through the minuter gnat-like groupes; it 
 settles for a moment on one of the lesser ferns, and a small 
 insectivorous creature, scarce larger than a rat, issues 
 noiselessly from its hole, and creeps stealthily towards it. 
 But there is the whirr of wings heard overhead, and, lo! a 
 monster descends, and the little mammal starts back into 
 its hole. 'Tis a winged dragon of the Oolite, a carnivor- 
 ous reptile, keen of eye and sharp of tooth, and that to the 
 head and jaws of the crocodile adds the neck of a bird, the 
 tail of an ordinary mammal, and that floats through the air 
 on leathern wings resembling those of the great vampire
 
 200 LECTURES ON GEOLOGY. 
 
 bat. We have seen, in the minute, rat-like creature, one 
 of the two known mammals of this vast land of the Oolite, 
 
 — the insect-eating AmpliUherium. ; and in the flying 
 reptile, one of its strangely organized Pterodactyls. 
 
 But hark! what sounds are these? Tramp, tramp, tr;imp, 
 
 — crash, crash. Tree-fern and club-moss, cycas and zamia, 
 yield to the force and momentum of some immense reptile, 
 and the colossal Iguanodon breaks through. He is tall as 
 the tallest elephant, but from tail to snout greatly more 
 than twice as long ; bears, like the rhinoceros, a short 
 horn on his snout; and has his jaws thickly implanted 
 with saw-like teeth. But, though formidable from his 
 great weight and strength, he possesses the comparative 
 inoffensiveness of the herbivorous animals ; and, with no 
 desire to attack, and no necessity to defend, he moves 
 slowly onward, deliberately munching, as he passes, the 
 succulent stems of the cycadacea. The sun is fast sinking, 
 and, as the light thickens, the reaches of the neighboring 
 river display their frequent dimples, and ever and, anon 
 long scaly backs are raised over its surface. Its numerous 
 crocodileans are astir; and now they quit the stream, and 
 we see its thick hedge-like lines of equisetacefe open and 
 again close, as they rustle through, to scour, in quest of 
 prey, the dank meadows that line its banks. There are 
 tortoises that will this evening find their protecting armor 
 of carapace and plastron all too weak, and close their long 
 lives of centuries. And now we saunter downwards to the 
 shore, and see the ground-swell breaking white in the 
 calm against ridges of coral scarce less white. The shores 
 are strewed with shells of ])carl, — the whorled Ammonite 
 and the Nautilus; and aniid the gleam of ganoidal scales, 
 reflected from the green depths beyond, we may see the 
 phosphoric trail of the Belemnitc!, and its path is over
 
 LECTURES ON GEOLOGY. 201 
 
 shells of strange form and name, — the sedentary Giyphaea, 
 the Pern a, and the Plagiostoma. 
 
 But lo! yet another monster. A snake-like form, sur- 
 mounted by a crocodilean head, rises high out of the water 
 "within yonder coral ledge, and the fiery, sinister eyes peer 
 inquiringly round, as if in quest of prey. The body is but 
 dimly seen ; but it is short and bulky compared witli the 
 swan-like neck, and mounted on paddles instead of limbs; 
 so that the entire creature, wholly unlike anything which 
 now exists, has been likened to a boa constrictor threaded 
 through the body of a turtle. We have looked upon the 
 Plesiosaurus. And now outside the ledge there is a huge 
 crocodilean head raised ; and a monstrous eye, huger than 
 that of any other living creature, — for it measures a full 
 foot across, — glares upon the slimmer and less powerful 
 reptile, and in an instant the long neck and small head dis- 
 appear. That monster of the immense eye, — an eye so 
 constructed that its focus can be altered at will, and made 
 to comprise either near or distant objects, and the organ 
 itself adapted either to examine microscopically or to ex- 
 plore as a telescope, — is another be-paddled reptile of the 
 the sea, the Ichthyosaurus, or fish-lizard. But the night 
 comes on, and the shadows of the woods and rocks deepen: 
 there are uncouth sounds along the beach and in the forest ; 
 and new monsters of yet stranger shape are dimly dis- 
 covered moving amid the uncertain gloom. Reptiles, rep- 
 tiles, reptiles, — flying, swimming, waddling, walking ; — 
 the age is that of the cold-blooded, ungenial reptile ; and, 
 save in the dwarf and inferior forms of the marsupials and 
 insectivora, not one of the honest mammals has yet ap- 
 peared. And now the moon rises in clouded majesty ; and 
 now her red wake brightens in one. long strip of the dark 
 sea; and we may mark where the Cetiosaurus, a sort of
 
 202 LECTURES ON GEOLOGY. 
 
 reptilian whale, comes into view as it crosses the lighted 
 tract, and is straightway lost in the gloom. But the night 
 grows dangerous, and these monster-haunted woods were 
 not j)lanted for man. Let us return then to the safer and 
 better furnished world of the present time, and to our 
 secure and quiet homes.
 
 LECTURE FIFTH. 
 
 The Lias of the Hill of Eathie — The Beauty of its Shores — Its Deposits, how 
 formed — Their Animal Organisms indicative of successive Platforms of Exist- 
 ences — The Laws of Generation and of Death — The Triassic System — Its 
 Economic and Geographic Importance — Animal Footprints, but no Fossil 
 Organisms found in it — The Science of Ichnolngy originated in this fact — Illus- 
 trated by the appearance of the Compensation I'ond, near Edinburgh, in 1842 — 
 The Phenomenon indicated by the Footprints in the Triassic System — The Trias- 
 sic and Permian Systems once regarded as one, under the name of the New Red 
 Sandstone — The Coal Measures in Scotland next in Order of Succession to the 
 Triassic System — Differences in the Organisms of the two Systems — Extent 
 of the Coal Measures of Scotland — Their Scenic Peculiarities — Ancient Flora 
 of the Carboniferous Period — Its Fauna — Its Reptiles and Reptile Fishes 
 — The other Organisms of the Period — G reat Depth of the System — The Pro- 
 cesses by which during countless Ages it had been formed. 
 
 The Lias forms, as I have already had occasion to re- 
 mark, the base of the great Oolitic system. I dealt in my 
 last address Avith the productions, vegetable and animal, of 
 those loug ages of the world's history which the various 
 deposits of this system represent, and attempted a restora- 
 tion of some of its more striking scenes, as they mnst haA^e 
 existed of old, in what is now Scotland. But in glancing 
 once more at the Lias, we must pass from the living to the 
 dead, — from the vital myriads that once were, to the 
 cemetery that contains their remains. I shall select as my 
 example a single Liassic deposit of Scotland, but in several 
 respects one of the most remarkable, — that of Eathie, on 
 the sliores of the Moray Frith, about four miles from the 
 town of Cromarty. And in visiting it in its character as a 
 great burial-ground, — the final resting-place, not only of
 
 204 LECTURES ON GEOLOGY. 
 
 2:)erished individuals, but also of extinct tribes and races, 
 and in scanning its strangely sculptured monuments, rough- 
 ened with hieroglyphics, to which living nature furnishes 
 the key, we may perhaps be permitted to indulge in some 
 of those reflections which so naturally suggest themselves 
 in solitary churchyards, or among the tombs of the ancient 
 dead. 
 
 The hill of Eathie is a picturesque eminence of granitic 
 gneiss, largely mixed with beds of hornblende schist, which 
 extends, in a long precipitous ridge, some five or six hun- 
 dred feet in height, along the northern side of the Moray 
 Frith, and forms one of a primary chain of hills, which, in 
 their upheaval, uptilted deposits of the Lias and Oolite. 
 The deposit wdiich the hill Eathie disturbed is exclusively 
 a Liassic one : the upturned edge of the base of the forma- 
 tion rests against the bottom of the hill ; and we may trace 
 the edges of its various upper deposits for several hundred 
 feet outwards, bed above bed, until, apparently near the 
 top of the formation, we lose them in the sea. There is a 
 wild beauty on the shores of Eathie. A selvage of com- 
 paratively level ground, that occupies the space between 
 the rocky beach and an inflection of the hill, seems em- 
 bosomed in solitude ; the naked scaurs and furze-covered 
 slopes, where the fox and the badger breed, interpose their 
 dizzy fence between it and the inhabited portions of the 
 country above ; while the rough unfrequented shore and 
 wide-spreading sea form the secluding barriers below. The 
 only human dwellings visible are the minute specks of 
 white that look out in the sunshine from the dim and 
 diluted blue of the opposite coast; and we may see the 
 lonely frith broadening and widening as it recedes from 
 the eye, and opens to the ocean in a direction so uninter- 
 rujited by land, that the waves, which, when the wind
 
 LECTURES ON GEOLOGY. 205 
 
 blows from the keen north, first begin to breiik on the dis- 
 tant headlands, and then come running up the coast, like 
 white coursers, may have heaved their first undulating 
 movements under the polar ice. The scene seems such a 
 one as the anchorite might choose to wear out life in, fiir 
 fi'om the society of fellow-man ; and we actually find, in 
 exploring its bosky thickets of wild rose and sloe-thorn, 
 that some anchorite of the olden time did make choice of 
 it. A gray shapeless hillock of lichened stone, shaded by 
 luxuriant tufts of fern, still bears the name of the old 
 chapel; and an adjacent spring, on whose overhanging 
 sprays of ivy M'e may occasionally detect minute tags of 
 linen and woollen cloth, — the offerings of a long-derived 
 superstition, not quite extinct in the district, — is still 
 known as the Saint's Well. But wdio the anchorite was, 
 tradition has long since forgot ; and it was only last year 
 that I succeeded in recovering the name of the saint from 
 an old man, whose father had been a farmer on the land 
 considerably more than a hundred years before. The 
 chapel and spring had been dedicated, he said, to St. Ken- 
 nat, — a name which we need scarce look for in the 
 Romish Calendar, but which designated, it is probable, 
 one of our old Culdee saints. 
 
 The various beds of the Eathie deposit, — all, save the 
 lowest, which consists of a blue adhesive clay, — are com- 
 posed of a dark, finely laminated shale ; and, varying in 
 thickness from thirty feet to thirty yards, they are curi- 
 ously separated from each other by bands of fossiliferous 
 limestone. And so impalpable a substance are these 
 shales, that, when subjected to calcination, which is neces- 
 sary to extract the bitumen with which they are charged, 
 and which gives them toughness and coherency, they re- 
 solve into a powder, used occasionally, from its extreme 
 
 18
 
 206 LECTURES OJf GEOLOGY. 
 
 fineness, in the cleaning of polislied brass and copper. 
 They were laid down, it is probable, in circumstances similar 
 to those in which, as described by the late Captain Basil 
 Hall, extensive deposits are now taking place in the Yellow 
 Sea of China. "At sunset," says Captain Hall, in the 
 narrative of his voyage to Loo-Choo, "no land could be 
 perceived from the mast-head, although we were in less 
 than five fathoms water. And before the day broke next 
 morning, the tide had fallen a whole fathom, which brought 
 the ship's bottom within thi'ee feet of the ground. It was 
 soon afterwards discovered that she was actually sailing 
 along Avith her keel in the mud, which was sufficiently in- 
 dicated by a long yellow train in our wake. Some incon- 
 venience was caused by this extreme shallowness, as it re- 
 tarded our headway, and aflfected the steering ; but there 
 was in reality not much dangex', as it was ascertained, by 
 forcing long poles into the ground, that for many fathoms 
 below the surface on which the sounding lead rested, and 
 from which level the depth of water is estimated, the bot- 
 tom consisted of nothuig but mud formed of an impalp- 
 able powder, without the least particle of sand or gravel." 
 The Liassic deposit of Eathie must have been of slow de- 
 position. It consists of laminae as thin as sheets of paste- 
 board, which, of course, shows that there was but little 
 deposited at a time, and pauses between each deposit. 
 And, though a soft muddy surface could have been of it- 
 self no proper habitat for the sedentary animals, — serpulae, 
 oysters, gryphites, and terebratulae, — we can find farther, 
 that they did, notwithstanding, find footing upon it, by at- 
 taching themselves to the dead shells of such of the sailing 
 or swimming molluscs. Ammonites and Belemnites, as died 
 over it, and left upon it their remains; from which we in- 
 fer that the pauses must have been very protracted, seeing
 
 LECTURES ON GEOLOGY. 207 
 
 that they gave time sufficient for the Terebratulae, — shells 
 that never moA-ed from the place in which they were origi- 
 nally fixed, — to grow up to maturity. The thin leaves of 
 these Liassic volumes must have been slowly formed and 
 deliberately written ; for as a series of volumes, reclining 
 against a granite pedestal in the geologic library of nature, 
 I used to find jDleasure in regarding them. The limestone 
 bands, curiously marbled with lignite, ichthyolite, and 
 shell, formed the stiff boarding ; and the thin pasteboard- 
 like laminae between, — tens and hundreds of thousands in 
 number in even the slimmer volumes, — cqmposed the 
 closely written leaves. For never did characters or figures 
 lie closer in a page than the organisms on the surfaces of 
 these leaf-like laminae. Permit me to present you from my 
 note-book with a few readings taken during a single visit 
 from these strange pages. 
 
 We insinuate our lever into a fissure of the shale, and 
 turn up a portion of one of the laminae, whose surface had 
 last seen the light when existing as part of the bottom of 
 the old Liassic sea, when more than half the formation had 
 still to be deposited. Is it not one of the prints of Sower- 
 by's "Mineral Conchology" that has opened up to us? 
 Nay, the shells lie too thickly for that, and there are too 
 many repetitions of organisms of the same species. The 
 drawing, too, is finer, and the shading seems produced 
 rather by such a degree of relief in the figures as may be 
 seen in those of an embossed card, than by any arrangement 
 of lighter and darker color. And yet the general tone of 
 the coloring, though dinmied by the action of untold cen- 
 turies, is still very striking. The ground of the tablet is 
 of a deep black, while the colors stand out in various 
 shades, from opaque to a silvery white, and from silvery 
 white to deep gray. There, for instance, is a group of
 
 208 LECTURES ON GEOLOGY. 
 
 lai'ge Ammonites, as if drawn in white chalk ; tJiere^ a clus- 
 ter of minute bivalves resembling Pectens, each of which 
 bears its thin film of silvery nacre; the7'e, a gracefully 
 formed Lima in deep neutral tint; while, lying athwart 
 the page, like the dark hawthorn leaf in Bewick's well- 
 known vignette, there are two slim sword-shaped leaves 
 colored in deep umber. We lay open a portion of another 
 page. The centre is occupied by a large Myacites, still 
 bearing a warm tint of yellowish brown, and which must 
 have been an exceedingly brilliant shell in its day ; there 
 is a Modiola, a smaller shell, but similar in tint, though not 
 quite so bright, lying a few inches away, with an assem- 
 blage of dark gray Gryphites of considerable size on the 
 one side, and on the other a fleet of minute Terebratulae, 
 that had been borne down and covered up by some 
 fresh deposit from above, when riding at their anchors. 
 We turn over yet another page. It is occupied exclu- 
 sively by Ammonites of various sizes, but all of one 
 species, as if a whole argosy, old and young, convoyes and 
 convoyed, had been Avrecked at once, and sent disabled 
 and dead to the bottom. And here we open yet another 
 page more. It bears a set of extremely slender Belem- 
 nites. They lie along and athwart, and in every possible 
 angle, like a heap of boarding-pikes thrown carelessly 
 down a vessel's deck on the surrender of the crew. Here, 
 too, is an assemblage of bright black plates, that shine like 
 pieces of japan work, the cerebral plates of some fish 
 of the ganoid order ; and here an immense accumulation 
 of minute glittering scales of a circular form. We apply 
 the microscope, and find every little interstice in the page 
 covered with organisms. And leaf after leaf, for tens and 
 hundreds of feet together, repeats the same strange story." 
 The great Alexandrian library, with its unsummed tomes
 
 LECTURES ON GEOLOGY. 20*J 
 
 of ancient literature, the accumulation of long ages, was 
 but a poor and meagre collection, scarce less puny in bulk 
 than recent in date, when compared with this vast and 
 wondrous library of the Scotch Lias. 
 
 Now, this Eathie deposit is a crowded burying-ground, 
 greatly more charged with remains of the dead, and more 
 thoroughly saturated with what was once animal matter, 
 than ever yet was city burying-ground in its most unsani- 
 tary state. Every limestone band or nodule, yields, when 
 struck by the hammer, the heavy fetid odor of corruption 
 and decay; and so charged is the laminated shale with an 
 animal-derived bitumen, that it flames in the fire as if " 
 it had been steeped in oil, and yields a carburetted hydro- 
 gen gas scarce less abundantly than some of our coals 
 of vegetable origin. The fact of the existence, through- 
 out all the geological ages, of the great law of death, is 
 a fact which must often press upon the geologist. Almost 
 all the materials of his history he derives from cenotaphs 
 and catacombs. He finds no inconsiderable portion of 
 the earth's crust composed of the remains of its ancient 
 inhabitants, — not of dead individuals merely, but also 
 of dead species, dead genera, nay, of even dead creations ; 
 and here, where the individual dead lie as thickly on the 
 surface of each of many thousand layers as leaves along 
 the forest glades in autumn, — here, where all the species 
 and many of the genera are dead, nay, where the Avhole 
 creation represented by its multitudinous organisms is 
 dead, — the great problem which this law of death pre- 
 sents comes upon the explorer in its most palpable and 
 urgent form. The noble verses of James Montgomery, 
 somewhat exagerative in their character when addressed 
 to a molehill, become as remarkable for their sober pro- 
 priety as for their beauty when employed here : 
 
 18*
 
 210 LECTURES ON GEOLOGY. 
 
 " Tell me, thou dust beneatli my feet, 
 Thou dust that once hadst breath, — 
 Tell me how many mortals meet 
 In this small hill of death? 
 
 By wafting winds and flooding rains, 
 
 From ocean, earth and sky. 
 Collected, here the frail remains 
 
 Of slumbering millions lie. 
 
 The mole that scoops, with curious toil, 
 
 Her subterranean bed, 
 Thinks not she ploughs so rich a soil, 
 
 And mines among the dead. 
 
 But 0! where'er she turns the ground. 
 
 My kindred earth I see ; 
 Once every atom of this mound 
 
 Lived, breathed, and felt like me. 
 
 Like me, these elder-born of clay 
 
 Enjoyed the cheerful light. 
 Bore the brief burden of a day, 
 
 And went to rest at night. 
 
 Methinks this dust yet heaves with breath, 
 
 Ten thousand pulses beat : 
 Tell me, in this small hill of death 
 
 How many mortals meet." 
 
 What does this inexorable law of death mean, or on 
 what principle does it depend ? In our own species it has 
 a moral significancy, — " Death reigned from Adam," and 
 though a pardonable mistake, no longer insisted on by 
 at least theologians of the higher class, the same moral 
 character, as a reflex influence, has been made to attach to 
 it in its inevitable connection with the inferior animals. 
 But in them, it seems to have no moral significancy. 
 
 Bacon makes a shrewd distinction, in one of his Essays, 
 between "death as the wages of sin," and death as "a 
 tribute due to nature;" and we can now fully appreciate
 
 LECTURES OX GEOLOGY. 211 
 
 the value of the distinction. For we now know that 
 while, as the wages of sin, it has reigned from but the 
 fall of Adam, it has reigned as a tribute due to nature 
 throughout the long lapse of the geologic ages from the 
 first beginnings of life upon our planet. What, then, does 
 this inexorable law of death mean ? and on what principle 
 does it depend ? 
 
 It was in mei-e cobweb toils that those Sadducees who 
 believed " not in angel, neither in spirit," endeavored to 
 entangle our Saviour, when they propounded to him the 
 case of the woman with the seven husbands, and de- 
 manded whose wife of the seven she was to be in the 
 Resurrection. But there was a jH-ofundity in the reply, 
 which the theologians of nearly two thousand years have, 
 I am disposed to think, failed adequately to comprehend. 
 "The children of this world marry and are given in mar- 
 riage," he said, "but the children of the Resurrection 
 neither many nor are given in marriage, neither can they 
 die any more." Now there seems to be a strictly logical 
 sequence between the two distinct portions of this pro- 
 position, — the enunciation that the denizens of the state 
 after death do not many, and the enunciation that they 
 do not die, which for eighteen centuries there was not 
 science enough in the world adequately to appreciate. 
 The mamage provision was simply a provision tanta- 
 mount to the original injunction, not of paradise merely, 
 but of every preceding period in which there were organi- 
 zations of matter possessed by the vital principle : " In- 
 crease and multiply, and replenish the earth." And all 
 geology presses upon us the conviction, so powerfully 
 enforced by the Liassic deposit at Eathie, that, from the 
 very nature of things, the law of generation and the law 
 of death, wherever space is limited, cannot be dissociated.
 
 212 LECTURES ON GEOLOGY. 
 
 Each of the multituclmous leaves of the Lias formed in 
 succession an upper surface, or j)ln.tforin, on which, for a 
 certain period of time in the world's history, living and 
 sentient creatures pursued the several instincts of their 
 natures, and then ceased to exist. And so immense, in 
 many instances, was the crowd, that, had the existence 
 of two platforms been restricted to the occupancy of only 
 one platform, they would have lacked footing. A dense 
 crowd of living men may find ample standing-room in an 
 ancient city churchyard, occupying, as they do, a difierent 
 stratum of space from that occupied by the dead; but 
 were the dead to revive and arise, it would be impossible 
 that the living could find in it the necessary standing- 
 room any longer. They would be jostled from their 
 places fiir beyond the limits of the inclosing wall. And 
 let us remember, that "the great globe itself which we 
 inherit " is all one vast burying-ground ; nor is it to one 
 stratum that the densely piled remains of its dead are 
 restricted, nor to one hundred, nor to one thousand, nor 
 yet to one hundred thousand strata. Even in this dejiosit 
 of the Eathie Lias, the successive platforms of the dead 
 may be reckoned up by thousands and tens of thousands ; 
 and it would be more possible that a fertile field should 
 have growing upon it at once the harvests of ten thou -and 
 succeeding autumns, than that any one of the platforms 
 should have living upon it at once the existences of all the 
 innumerable platforms above and below. The great law 
 " increase and multiply " gave to each platform its count- 
 less crowds ; and to make room for the continuous opera- 
 tion of tliis law, the other great law of death came into 
 action, and so the generations of succeeding periods found 
 space to pursue their various instincts on platforms com- 
 posed in no small part of the perished generations fi'om
 
 LECTURES ON GEOLOGY. 213 
 
 which they had sprung. Throughout the whole incalcula- 
 ble past of our planet, — throughout all its unmeasured and 
 unraeasurable periods, — the laws of production and decay 
 have gone inseparably together ; they were twin stars on 
 the horizon, tinged by the complementary colors, and so 
 inseparably associated, that the appearance of the one 
 always heralded the rise of the other. And to my mind 
 at least, it does seem demonstrative of the full-orbed and 
 perfect wisdom of the Divine Master of the Theolo- 
 gians, that He, with tliat quiet simplicity which Pascal so 
 well designates the characteristic style of Godhead, and 
 with a logic too profound to be appreciated at the time, 
 should have coupled together the twin laws of production 
 and decay, as equally inadmissible into that future state in 
 which the life of man is to be no longer 
 
 " Summed up in birthdays and in sepulchres." 
 
 " The children of the resurrection neither marry nor are 
 given in man-iage, neither can they die any more." 
 
 From the Oolite, with its Liassic base, we pass on to 
 the Triassic system, — a deposit less characteristically de- 
 veloped in England than on the Continent, but of much 
 economic importance, from those vast beds of rock-salt 
 which, in Britain, at least, are exclusively restricted to 
 this system ; and of considerable geographic importance, 
 from its great lateral extent. In Scotland^ it occupies 
 rather more than a hundred square miles of surface, chiefly 
 in Dumfriesshire, along the northern shores of the Solway, 
 
 ^ Tliere is good reason to believe that the red rocks overlying the coal 
 of Cumberland, the red sandstones of Corncockle Muir, near Dumfries, 
 the Ayrshire red sandstones, and those of the Isle of AiTan, are all of the 
 Permian, not Triassic, epoch. See " Siluria," new edition, p. 351.— 
 W. S. S.
 
 214 LECTURES ON GEOLOGY. 
 
 and in the line of boundary between the two kingdoms, 
 where it can boast, among its other celebrities, of the 
 famous village of Gretna Green, and the whole of Gretna 
 parish. In England it is chiefly remarkable, in a scenic 
 point of view, for its extreme flatness : its main feature is 
 a want oi features. It was, however, at one time, noto- 
 rious for its ponds and marshes, consequents of the imper- 
 fect drainage incident to flat low sm-faces when of great 
 extent; and in Scotland, though so much more limited in 
 area, it bears this character still. No fossil organisms have 
 yet been found in this deposit in Scotland : it contains, 
 however, in abundance, traces of the ancient inhabitants, 
 even more curiously imprinted on the stone than if they 
 had left in it the remains of their framework ; and is 
 interesting as the field in which, from the sedulous study 
 of these, and undeterred by the skepticism of some of our 
 highest authorities, the late Dr. Duncan, of Ruthwell, laid 
 the first foundations of that curious and instructive de- 
 partment of geologic science since known as Ichnology. 
 The strange reptiles of this ancient time, in passing over 
 the tide-uncovered beaches of the district, left their foot- 
 steps imprinted in the yielding sand ; and in this sand, no 
 longer yielding, but hardened long ages ago into solid 
 rock, the footsteps still remain. And with truly wonder- 
 ful revelations, — revelations of things the most evanescent 
 in themselves, and of incidents regarding which it might 
 seem extravagant to expect that any record should remain, 
 do we find these strange markings charged. They even 
 tell us how the rains of that remote age descended, and 
 how its winds blew. 
 
 Let us see whether we cannot indicate a few of at least 
 the simpler principles of this department of science. The 
 artificial sheet of water situated among the Pentlands, and
 
 LECTURES ON GEOLOGY. 215 
 
 known as the Compensation Pond, was laid dry, during 
 the w^arm summer of 1842, to the depth of ten fathoms ; 
 and as a lake bottom ten fathoms from the surface, is not 
 often seen, I A'isited it, in the hope of acquiring a few 
 ficts that might be of use to me among the rocks. What 
 first struck me, in surveying the brown sun-baked bottom 
 from the shore, was the manner in which it had cracked, 
 in the drying, into irregularly jiolygonal partings, and that 
 the ripple-markings with which it was fretted extended 
 along only a narrow border, where the water had been 
 shallow enough to permit the winds or supei-ficial currents 
 to act on the soft clay beneath. As I descended, I found 
 the surface between the partings indented with numerous 
 well-marked tracks of the feet of men and animals, made 
 while the clay was yet soft, and now fixed in it by the 
 drying process, like the mark of the stamp in an ancient 
 brick. And some of these tracks were charged with 
 little snatches of incident, which they told in a style 
 remarkably intelligible and clear. At one place, for in- 
 stance, I found the footprints of some four or five sheep. 
 They struck out towards the middle of the hollow, but 
 turned upwards at a certain point, in an abrupt angle, 
 towards the bank they had quitted, and the marks of 
 increased speed became palpable. The prints, instead of 
 being leisurely set down, so as to make impressions as 
 sharp-edged as if they had been carved or modelled in the 
 clay, were elongated by being thi'own out backwards, and 
 the strides were considerably longer than those in the 
 downward line. And, bearing direct on the retreating 
 footprints from the opposite bank, and also exhibiting 
 signs of haste, I detected the track of a dog. The details 
 of the incident thus recorded in the hardened mud were 
 complete. The sheep had gone down into the hollow
 
 21G LECTURES ON GEOLOGY. 
 
 shortly after the retreat of the waters, and while it was 
 yet soft; and the dog, either acting upon his own judg- 
 ment, or on that of the shepherd, had driven them back. 
 A little firther on I found the prints of a shoed foot of 
 small size. They passed onwards across the hollow, the 
 steps getting deeper and deeper as they went, until near 
 the middle, where there were a few irregular steps, shorter, 
 deeper, and more broken than any of the others; and 
 then the marks of the small shoes altogether disappeared, 
 and a small naked foot of cori'esponding size took their 
 place, and formed a long line to the opposite bank. In 
 this case, as in the other, the details of the incident were 
 clear. Some urchin, in venturing across when the mud 
 was yet soft and deep, after wading nearly half the way 
 shod, had deemed it more prudent to wade the rest of 
 it barefoot than to bemire his stockings. In each case 
 the incident was recorded in peculiar characters ; and to 
 read such characters aright, when inscribed upon the 
 rocks, forms part of the proper work of the ichnologist. 
 His key, so far at least as mere incident is concerned, is 
 the key of circumstantial evidence ; and very curious 
 events, as I have said, — events which one would scarce 
 expect to find recorded in the strata of ancient systems, — 
 does it at times serve to unlock. 
 
 In some remote and misty age, lost in the deep obscu- 
 rity of the unreckoned eternity that hath passed, but 
 which we have learned to designate as the Triassic period, 
 a strangely formed reptile, unlike anything which now 
 exists, paced slowly across the ripple-marked sands of a 
 lake or estuary.^ It more resembled a frog or toad than 
 
 1 Reptiles arc known to liave existed from the period of the Old Red 
 Sandstone, where their tracks have lately been discovered. The reptiles 
 of the Coal are of the Batrachian type; the Permian reptiles are allied to
 
 LECTURES ON GEOLOGY. 217 
 
 any animal with which we are now acquainted ; but to 
 the batrachian peculiarities it added certain crocodilian 
 features, and in size nearly rivalled one of our small High- 
 land oxen. The prints it made very much resembled 
 those of a human hand ; but, as in the frog, the hinder 
 paws were fully thrice the size of the fore ones ; and there 
 was a gigantic massiveness in the fingers and thumb, which 
 those of the human hand never possess. Onward the crea- 
 ture went, slowly and deliberately, on some unknown 
 errand, prompted by its instincts; and as the margin of 
 the sea or lake, lately deserted by the water, possessed the 
 necessary plasticity, it retained every impression sharply. 
 The wind was blowing strongly at the time, and the 
 heavens were dark with a gathering shower. On came 
 the rain ; the drops were heavy and large ; and, beaten 
 aslant by the wind, they penetrated the sand, not perpen- 
 dicularly, as they would have done had they fallen during 
 a calm, but at a considerable angle. But such was the 
 weight of the reptile, that, though the rain-drops sank 
 deeply into the sand on every side, they made but com- 
 paratively faint impressions in its footprints, where the 
 compressive effect of its tread rendered the resisting mass 
 more firm. "We have here, in a single slab," says Dr. 
 Buckland, in referring, in his address to the Geological 
 Society for 1840, to these very footprints, and their ad- 
 juncts, — "we have here, in a single slab, a combination 
 of proofs as to meteoric, hydrostatic, and locomotive phe- 
 nomena, which occurred at a time incalculably remote, in 
 the atmosphere, the water, and the movements of animals, 
 from which we infer, with the certainty of cumulative 
 circumstantial evidence, the direction of the wind, the 
 
 Batrachians and Monitors; wliilc the reptiles of the Trias are Labyrintho- 
 dont. — W. S.S. 
 
 19
 
 218 LECTURES ON GEOLOGY. 
 
 depth and course of the water, and the quarter towards 
 which the animals were passing. The latter is indicated 
 by the direction of the footsteps which form the track; 
 the size and curvatui-e of the ripple-marks on the sand, 
 now converted into sandstone, show the depth and direc- 
 tion of the current ; while the oblique impressions of the 
 rain-droi^s register the point from which the wind was 
 blowing at or about the time when the animals were 
 passing."^ There is another scarce less curious or less 
 minutely recorded incident inscribed on a slab of the 
 same formation, figured and described by Sir Roderick 
 Murchison. It is impressed by the footprints of some 
 betailed batrachian, greatly less bulky than the other, that 
 went Avaddling along much at its leisure, like the sheep in 
 the nursery rhyme, "trailing its tail behind it," There 
 is a double track of footprints on the slab, — those of 
 the right and left feet ; in the middle, between the two, 
 lies the long groove formed by the tail, — a groove con- 
 tinuous, but slightly zig-zagged, to indicate the waddle. 
 The creature, half-way in its course, lay down to rest, hav- 
 ing apparently not much to do, and its abdomen formed 
 a slight hollow in the sand beneath. Again rising to its 
 feet, it sprawled a little, and the hinder part of its body, 
 in getting into motion, fretted the portion of the surface 
 that furnished what we may term the fulcrum of the move- 
 ment, into two wave-like curves. Here, again, are we 
 furnished, from the most remote antiquity, with a piece 
 of narrative of a kind Avhich assuredly we could scarce 
 expect to find enduringly recorded in the rocks. Various 
 reptiles have left curious passages of their history of this 
 
 1 The Lahyi-intlwdon Buchiandi (Lloyd), formerly believed to be a Trias- 
 sic reptile, is now ranked ;is belonjjini; to the Pcrniian fauna. See Baiii- 
 say. Quart. Jour. Geol. Soc , Vol. 11. p. 198. — W. S. S.
 
 LECTURES ON GEOLOGY. 219 
 
 kind inscribed on the sandstones of Dumfi-iesshire ; and 
 as Sir William Jardine, the proprietor of some of the 
 quarries, has set himself to the work of illustration, the 
 geologist may soon hope to be put in possession of a mon- 
 ograph at once worthy of the subject and of so distin- 
 guished a naturalist.^ The footprints first observed by 
 Dr. Duncan Avere chiefly those of tortoises ; but there also 
 exist in the rock numerous tracks of the huge batrachians 
 of the period, with traces of a small animal, scarce larger 
 than a rat; and of a nameless, nondescript creature, whose 
 footprints might at first glance almost be mistaken for 
 those of a horse, but the marks of whose toes have been 
 traced, in some of the impressions, outside the ring of 
 the apparent hoo£^ And this is all we yet know of these 
 reptilian Triassic inhabitants of Scotland. Robinson Cru- 
 soe has gone down to the sea-shore, and seen, much to his 
 astonishment, the print of a savage foot in the sand. 
 
 According to an old, but not very old, style of nomencla- 
 ture, derived from mineralogical character not yet wholly 
 obsolete, the two systems, Triassic and Permian, used to 
 be included under one general head, as the New Red 
 Sandstone, or the Bunter Sandstone of Werner and Jame- 
 son. And certainly the mere mineralogist might find it 
 no easy matter to draw a line between them. Up to a 
 certain point in the ascending scale there occur on the 
 Continent strata of a Red Sandstone, known as the Lower 
 Bunter ; and immediately over it, a Red Sandstone known 
 as the Upj^er Bunter.^ They lie conformably to each 
 
 1 See Sir William Jardine's work on the "Ichnology of Annandale." 
 
 2 Chdichnus Titan and Gigas Jardine. — W. S. S. 
 
 3 The Bunter sandstein and Bnnter schiefer; of which the Bunter sand' 
 stein is now ranked as lowest, Trias, and the Bunter schiefer as upper, 
 Permian. — W. S. S.
 
 220 LECTURES ON GEOLOGY. 
 
 other, as if they had been deposited in immediate succes- 
 sion in a still sea : there are no traces of physical convul- 
 sion; the earthquake and the tornado had slept at the 
 time : there was no devastating inundation of molten fire, 
 nor overwhelming wave of translation ; — 
 
 " It was not in the battle; no tempest gave the shock: " 
 
 and yet that undisturbed horizontal line marks where one 
 creation ended and another began. It was held at one 
 time that there was not a single organism, vegetable or 
 animal, common to the two great divisions to which these 
 sandstone beds belong ; but there now seems to rest some 
 doubt on the point. In an insulated district of France, 
 plants of the Coal Measures have been found in a deposit 
 containing Belemnites ; and it is held that the Belemnite 
 belongs exclusively to the great Secondary division. But 
 the specific standing of these Belemnites still remains to 
 be determined : it is possible they may not be Secondary 
 forms ; and it has been suggested by M. Michelin, a dis- 
 tinguished French geologist, that generically the Belem- 
 nite may not be of the premised importance in reference 
 to the age of these Tarentaise beds. " He is inclined," we 
 find him saying, " to consider it an instance of the occur- 
 rence of the Belemnite form in the Carboniferous period, 
 rather than of the continuance of the same species of 
 plants through several successive epochs." 
 
 But, leaving it to the future researches of geologists to 
 determine whether there be any, and, if so, how many, 
 organisms common to the Secondary and Palaeozoic divis- 
 ions, a very slight acquaintance with fossils is sufficient to 
 show that between the types of organic nature in these 
 two great divisions there exist differences and distinctions 
 of the broadest and most palpable kind. In passing up-
 
 LECTURES ON GEOLOGY. 221 
 
 wards from the Triassic to the Permian, we seem to pass, 
 not merely from one dynasty to another, but, if I may dare 
 employ such a term, from one dispensation to another. 
 So broad are the differences, that they affect whole classes 
 of the animal kingdom. In the class of fishes, for instance, 
 an entire change takes place in the form of the tail. There 
 are a few ichthyic families in the present day, such as the 
 sharks and sturgeons, that have unequally-lobed tails, from 
 the circumstance that a prolongation of the vertebral col- 
 umn runs into the upper lobe ; whereas in perhaps nine- 
 teen-twentieths of all the existing families, the vertebral 
 column stops short, as in the osseous fishes common at our 
 tables, a little over the lobes, to form for them a medial 
 basis, and the lobes themselves are equal. And this equal- 
 lobed, or, as it is termed, homocercal condition, is the pre- 
 vailing one, not only in the j^resent time, but in all the 
 Tertiary and in all the Secondary ages, up till the close of 
 the Triassic system. And then, sudden as the shifting of 
 a scene, or as one of the abrupt transitions of a dream, we 
 find, immediately on entering the great Palaeozoic division, 
 an entire change. The unequal-lobed or heterocercal tail 
 becomes not only the jDrevailing, but the only form, save 
 in a few exceptional cases, as in that of the Coccosteus of 
 the Old Red Sandstone, where there were no lobes at all, 
 or as in that of its contemporary the Diplopterus^ where 
 the lobes strike out laterally from a prolongation of the 
 column. In short, the equally-lobed tail ceases with the 
 Trias, to reappear no more, and the unequally-lobed tail 
 takes its place. Similar changes manifest themselves in 
 other divisions and classes of the animal kingdom. Waiv- 
 ing for the present the question raised by the French geol- 
 ogist, M. Michelin, in Britain at least the Belemnite, so 
 abundant in the Secondary formations, and so characteris- 
 
 19*
 
 222 LECTURES ON GEOLOGY. 
 
 tic of them, has no place among the formations of the 
 Palaeozoic period. Save, too, in a few rare and somewhat 
 equivocal species, the equally characteristic Ammonite dis- 
 appears.^ We take leave also of the scarce less character- 
 istic Gryphites, of the Trigonia, Plagiostoma, and Perna, 
 with several other well-marked types of shell ; but we find 
 their places amply occupied by types exclusively Palaeo- 
 zoic. The Orthoceratites, straight, conical, chambered 
 shells, anticipated, we see, the place of the Belemnites; 
 the Goniatites, that of the Ammonites proper ; the Beller- 
 ophon and the Euomphalus, unseen in any other period, 
 fall into the general group, and add to the peculiarity of 
 its aspect; with a whole array of unwonted forms among 
 the brachiopoda, such as Spii'ifers, Producta, Atrypa, and 
 Pentamerus, etc., etc. But it was perhaps in the vegetable 
 world that the Palaeozoic ages most remarkably differed 
 from those of the subsequent periods of the geologist, 
 whether Secondary, Tertiary, or Recent. We read in the 
 older poets, of enchanted forests ; but the true enchanted, 
 forests, stranger, in their green luxuriance, than poet ever 
 yet fancied, and where the botanist, surrounded by irre- 
 ducible shapes that would take no place in his systems, 
 might well deem himself in a wild dream, were the forests 
 of the Coal Measures. 
 
 The Coal Measures of Scotland occujjy about two thou- 
 sand square miles of surface, and, though much overflown 
 by igneous rock, and occasionally broken through by 
 patches of Old Red Sandstone, run diagonally across the 
 country, from sea to sea, in a tolerably well-defined belt, 
 nearly parallel to the line of tlie southern flank of the 
 Grampians. Throughout their entire extent they owe 
 
 1 These views require imicli modification. See Sir C. Lyell's " Supple- 
 ments," 18.'57. — W. S. S.
 
 LECTURES ON GEOLOGY. 223 
 
 their scenic peculianties to the trap ; but where least dis- 
 turbed, as in the Dalkeith coal-field, they are of an incon- 
 spicuous, low-featured character, and chiefly remarkable 
 for their rich fields, as to the east of Edinburgh, between 
 the Arthur Seat group of hills and the Garlton hills near 
 Haddington ; or for their romantic dells and soft pastoral 
 valleys, such as Dryden Dell, or the valley of Lasswade, 
 or, to enumerate two other well-known rej^resentative 
 localities in one stanza, borrowed from Macneil, 
 
 " Roslin's gowany braes sae bonny, 
 Crags and water, woods and glen; 
 Roslin's banks, unpeered by ony, 
 Save the Muse's, Hawthornden." 
 
 The coal-fields owe some. of their more characteristic fea- 
 tures, especially in the sister kingdom, to man. The tall 
 chimneys, ever belching out smoke ; the thickly-sown en- 
 gine-houses, with the ever-recurring clank of the engines, 
 and the slow-measured motion of their outstretched arms 
 seen far against the sky; the involved fretwork of rail- 
 ways, connected with some main arterial branch, along 
 which the trjiveller ever and anon marks the frequent 
 train sweejDing by, laden with coals for the distant city ; 
 the long flat lines of low cottages, the homes of the poor 
 colliers; and here and there, where the ironstone bands 
 occur, a group of smelting furnaces ; — all serve to mark 
 the Coal Measures, and to distinguish them from every 
 other system. And such — striking off" the peculiarities 
 of the trap, which has no necessary connection Avith the 
 Carboniferous system, but is common, in some one j^art of 
 the world or another, to all the systems — are some of the 
 features, natural and superinduced, of this most important, 
 in an economic point of view, of all the geologic forma-
 
 224 LECTURES ON GEOLOGY. 
 
 tions. They are, as I have said, of no very prominent 
 character. The poet Delta describes, in a fine stanza, the 
 scenei-y around and to the east of Edinburgh. But though 
 the area which the landscape includes contains one of our 
 most considerable coal-basins, — a basin many square miles 
 in extent, — it does not furnish him with a single descrip- 
 tive reference. Almost all those bolder and more charac- 
 teristic features of the scene which his pencil exquisitely 
 touches and relieves, it owes to the igneous rocks. 
 
 " Traced in a map the landscape lies, 
 
 In cultured beauty stretching wide; 
 There Pentland's green acclivities; 
 
 There ocean with its azure tide; 
 There Ai'thui' Seat, and, gleaming through 
 
 Thy southern wing, Dunedin blue; 
 While in the orient, Lammer's daughters, 
 
 A distant giant range are seen ; 
 North Berwick Law, with cone of green. 
 
 And Bass amid the waters. " 
 
 The ancient scenery of the Coal Measures would be 
 greatly more difficult to trace. As we recede among the 
 extinct creations farther and farther from the present time, 
 the forms become more strange, and less reducible to 
 those compartments to which we assign known classes and 
 existing types. Our more solid principles of classification 
 desert us, and Ave are content to substitute instead, remote 
 analogies and distant resemblances. We say of one family 
 of plants that they somewhat resemble club-mosses, shot 
 up in bulk and height into forest trees ; and of another 
 family, that they would be not very unlike the horsetails 
 of our morasses, did horsetails rival in size larches of some 
 twenty or thirty years' growth. In referring to yet other 
 families, we can avail ourselves — so outre are their forms
 
 LECTURES ON GEOLOGY. 225 
 
 — of no resemblance at all: we can simply figure and 
 describe, and draw our illustrative comparisons, if we em- 
 ploy such, rather from the departments of art than of 
 nature. It is possible that, were some of our higher bot- 
 anists — our Balfours, Browns, and Grevilles — permitted 
 to range for a day over the broad plains of Jupiter, or 
 araid the bright sunshiny vales of Mercury or Venus, even 
 they might be but able to tell us, on their return, of gor- 
 geous floras, that defied all their old rules of classification, 
 and which could be illustrated from that of our own 
 planet only by distant resemblances and remote analogies. 
 And assuredly such would be the case, could they, through 
 the exercise of some clairvoyant faculty, be enabled to 
 journey for millions and millions of years into the remote 
 past, and to spend a few enchanted hours amid the dense 
 and sombre thickets of a Carboniferous forest. Shall I 
 venture on communicating to this audience a snatch of 
 personal history, illustrative of the mode in which I myself 
 arrived, many years ago, at my earliest formed concep- 
 tions regarding the old flora of the Coal Measures ? 
 
 The first perusal of "Gulliver's Travels" forms an era in 
 the life of a boy, if the work come in his way at the right 
 time ; and I was fortunate enough to secure my first read- 
 ing of it at the mature age of eight years. For weeks, 
 months, years after, my imagination was filled with the 
 little men and little women, and with at least one scene 
 laid in the country of the very tall men, — the scene in 
 which Gulliver, after wandering amid grass that rose 
 twenty feet over his head, lost himself in a vast thicket 
 of barley forty feet high. I became the owner, in fancy, 
 of a colony of little men ; I had little men for inhabiting 
 the little houses Avhich I built, for tilling ray apron- 
 breadth of a garden, and for sailing my little ship ; and,
 
 226 LECTURES ON GEOLOGY . 
 
 coupling with the men of LiUiput the scene in Brobidgnag, 
 I often set myself to imagine, when playing truant all 
 alone on the solitary slopes or amid the rocky dells of 
 Driemiorie, how the little creatures, who were sure always 
 to accompany me on these occasions, would be impressed 
 by the surrounding vignette-like scenes and mere pictur- 
 esque productions, exaggerated on hill and in hollow, by 
 their own minuteness, into great size. I have imagined 
 them threading their way through dark and lofty forests 
 of bracken fifty feet high, or admiring on the hill-side 
 some enormous club-moss, that stretched out its green 
 hairy arms over the soil for whole roods, or arrested at the 
 edge of some dangerous and dreary morass by hedges 
 of gigantic horsetail, that bore atop their many-windowed, 
 club-like cones, twenty feet over the dank surface, and 
 that shot forth at every joint their green verticillate leaves 
 in rings huge as coach-wheels. And while I thus thought, 
 or rather dreamed, for my Lilliputian companions, I be- 
 came for the time a Lilliputian myself, — saw the minute 
 in nature as if through a magnifying glass, — roamed in 
 fancy under ferns that had shot up into trees, — and saw 
 the dark cones of the equisetaceae stand up over their 
 spiky branches some six yards or so above head. But 
 these day-visions belonged to an early period : dreams 
 of at least a severer, if not more solid cast, dispossessed 
 the little men and women of the place they had occupied; 
 and I had learned to think of the wondrous tale of Swift 
 as one of the most powerful but least genial of all the 
 satires which the errors and perversions of poor humanity 
 have ever provoked, Avhen in the year 1824 I formed my 
 first practical acquaintance with the flora of the Coal 
 Measures. I was engaged as a stone-cutter, a few miles 
 ftom Edinburgh, in making some additions, in the old
 
 LECTURES ON GEOLOGY. 227 
 
 English style, to an ancient mansion-house ; and the stone 
 in which I wrought, — a curiously variegated sandstone, 
 derived from a quarry since shut uj^, — was, I soon found, 
 exceedingly rich in organic casts and impressions. They 
 were exclusively vegetable. Often have I detected in the 
 rude block jjlaced before me, to be fashioned into some 
 moulded transom or carved mullion, fi-agments of a sculp- 
 ture which I might in vain attempt to n\'Bl, — the forked 
 stems of Lepidodendra, fretted into scales that, save for 
 theif greater delicacy and beauty, might have reminded 
 the antiquary of the sculptured corslet of scale-armor 
 on the effigies of some ancient knight; the straight- 
 stemmed Calamite, fluted from joint to joint, like the 
 shaft of some miniature column of the Grecian Doric; 
 the Sigillaria, also a fluted column, but of a more mere- 
 tricious school than that of Greece, for it was richly 
 carved between the flutings ; the Stigmaria, fretted over, 
 with its eye-lit holes curiously connected by delicately- 
 waved lines ; and occasionally the elaborately ornate 
 TJlodendron, with its rows of circular scars, that seemed 
 to have been subjected to the lathe of an ornamental 
 turner, and its general surfice fretted over with what 
 seemed to be nicely sculptured leaves, such as we some- 
 times see on a Corinthian torus. It was not easy, more 
 than a quarter of a century ago, when Sir Roderick Mur- 
 chison was still an officer of dragoons, Sir Charles Lyell 
 prosecuting the study of English law, and Dr. Buckland 
 still engaged with his theory of the Flood, which he had 
 given to the world only the previous year, — it was not 
 easy, I say, for a working man to have such questions 
 solved as these fossils of the Coal Measures served to 
 raise. But they tcere, at length, in some measure solved. 
 I was taught to look to those forms of the existing flora
 
 228 LECTURES ON GEOLOGY. 
 
 of our country that most resembled the forms of its flora 
 during the Carboniferous period. And, strange to tell, 
 I found I had just to fall back on my old juvenile imag- 
 inings, and to form my first approximate conceptions of 
 the forests of the Coal Measures by learning to look at 
 our ferns, club-mosses, and equisetacese, with the eye of 
 some wandering traveller of Lilliput, lost amid their entan- 
 glements, like Gulliver among those of the fields of Brob- 
 dignag. When sauntering, after the work of the day was 
 over, along the edge of some wood-embosomed streamlet, 
 where the horsetail rose thick and rank in the danker 
 hollows, and the fern shot out its fronds from the drier 
 banks, I had to sink in fimcy, as of old, into a manikin 
 of a few inches, and to see intertropical jungles in the 
 tangled grasses and thickly interlaced equisetacese, and 
 tall trees in the herbaceous plants and the shrubs. 
 
 But many a wanting feature had to be supplied, and 
 many an existing one altered. Amid forests of arbora- 
 ceous ferns, tall as our second-class trees, there stood 
 up gigantic club-mosses thicker than the body of a man, 
 and from sixty to eighty feet in height ; more than a hun- 
 dred and fifty species of smaller ferns, and about one third 
 that number of smaller species of club-mosses, clothed the 
 oj^ener country ; and along the frequent marshes and lakes 
 that covered vast tracts of its flat sui-face, or the sluggish 
 rivers that winded through it, there flourished huge 
 thickets of equisetacese, of from twelve to fourteen difierent 
 species, tall, some of them, as the masts of pinnaces, and 
 thick and impenetrable as the fairy hedge that surrounded 
 the palace of the sleeping beauty. But among these 
 forms of the A'cgetable world, that, at least through the 
 blue steaming vapor of so dank a land, seem but the 
 more familiar forms of our iochans and hill-sides many
 
 LECTURES ON GEOLOGY. 229 
 
 times magnified, there arise strange floral shapes, among 
 which we can recognize no existing type. The Uloden- 
 dron, bearing along its carved trunk, on two of its sides, 
 rectilinear strips of cones, like rows of buttons on the 
 dress of a boy, and the ornately tatooed Sigillaria, lined 
 longitudinally, and w^ith its thickly-planted vertical rows 
 of leaves bristling from its stem and larger boughs, resem- 
 ble no vegetable productions which the earth now yields. 
 The landscape, too, has its intertropical forms, — what 
 seem gigantic Cacti, with thickets of canes, and a few 
 species of palms. And, where here and there a flat hil- 
 lock rises a few yards over the general level, we see 
 groups of noble Araucarians raising their green tops a 
 hundred and fifty feet over the plain. And yet, rich as 
 the flora of the period may seem in individuals, and 
 though it cumbers the soil with a luxuriance witnessed in 
 our own times only among the minuter forms, it is, in all 
 save size and bulk, a poor and low flora, after all. The 
 Pines and Araucarians form its only forest-trees. We fail 
 to meet on its plains a single dicotyledonous plant on 
 which a herbivorous mammal could browse. Its Lycopo- 
 daceae are covered over with catkin-like cones ; there are 
 cones on its Ulodendra, cones on its Equisetaceae, cones 
 on its Araucarians, cones on its Pines ; but not a single 
 fruit have we yet found good for the use of man. Kor, 
 after the first impression of novelty has passed away, is 
 there much even to gratify the sight. The marvel of 
 oraately-carved trunks and well-balanced fronds soon palls 
 on the sense ; and the prevalence of those spiky recti- 
 linear forms in the scene which Wordsworth could regard 
 as such deformities in landscape, and which James Gra- 
 hame so deprecates in his " Georgics," " lies like a load on 
 the weary eye." Nature labors in the production of huge 
 
 20
 
 230 LECTURES ON GEOLOGY. 
 
 immaturities ; neither man, the monarch, nor his higher 
 subjects, the mammals, have yet appeared; and it is all 
 too palpable that that garden has not yet been planted, 
 out of the ground of which there shall grow " every tree 
 that is pleasant to the sight and good for food." 
 
 Some of the gigantic forms of these jDrimeval forests we 
 can only vaguely and imperfectly illustrate by the dwarf 
 productions of our present moors and morasses ; and some 
 of them we fail to connect, by the links of general resem- 
 blance, with aught in the vegetable kingdom that now 
 lives. Regarded as a whole, the flora of the Carboniferous 
 age seems as remote in its analogues from that which now 
 exists, as remote in the period during which it flourished. 
 There are, however, at least two families of plants which 
 bear, not a loose and general, but a minute and thorough 
 resemblance, to families which also existed during the 
 great Secondary and Tertiary periods, and which still con- 
 tinue to occupy a large space among the recent vegetable 
 forms. And these are the Fern and the Pine families. 
 All the species have become extinct over and over again ; 
 but the families, and many of the genera, are ever repro- 
 duced ; and, so far as we know, this earth never possessed 
 a terrestrial flora that had not its ferns and its pines. In 
 all the other divisions and classes of the organic world 
 there are also favorite families, such as the Tortoises among 
 reptiles, the Cestracions among fishes, the Nautilus among 
 Cephalopodes, and the Terebratula among Brachipods. 
 There are few geologic formations in which either the 
 remains or the footprints of Tortoises have not been de- 
 tected; there seems never to have been an ocean that had 
 not its Cestracion ; the Nautilus lived in every age from 
 the times of the Lower Silurian deposits down to the pres- 
 ent day ; and, after disinterring specimens of fossil terebra-
 
 LECTURES ON GEOLOGY. 231 
 
 tula from our Grauwackes, our Mountain Limestones, our 
 Oolites, and our Chalk Flints, we may cast the drag in the 
 deeper lochs of the Western Highlands, and bring up the 
 living animals, fast anchored by their fleshy cables, to 
 stones and shells. We can scarce glance over a group 
 of fossils of the two earlier divisions, the Secondary and 
 the Palceozoic, which we do not find divisible into two 
 classes of types, — the types which still remain, and the 
 types which have disappeared. But why the one set of 
 forms should have been so repeatedly called into being, 
 while the other set was suiFered to become obsolete, we 
 cannot so much as surmise. In visiting some old family 
 library that has received no accession to its catalogue for 
 perhaps more than a century, one is interested in marking 
 its more vivacious classes of works — its ShaksjDcares, 
 Robinson Crusoes, and Pilgrim's Progresses — in their 
 first, or at least, earlier editions, ranged side by side with 
 obsolete, long-forgotten volumes, their contemporaries, 
 with whose unfamiliar titles we cannot connect a single 
 association. And exactly such is the class of fiicts with 
 which the geologist is called on to deal. He finds an 
 immense multiplication of editions in the case of some 
 particular type of fish, plant, or shell ; and in the case of 
 other types, no after instance of republication, or repub- 
 lication in merely a few restricted instances, and during 
 a limited terra. But while it is always easy to say why, 
 in the race of editions, the one class of writings should 
 have been arrested at the starting-post, and the other 
 class should go down to be contemporary with every after 
 production of authorship until the cultivation of letters 
 shall have ceased, the geologist finds himself wholly una- 
 ble to lay hold of any critical canon through which to 
 determine why, in the organic world, one class of types
 
 232 LECTURES ON GEOLOGY. 
 
 should be so often republished, and another so perempto- 
 rily suppressed. This far, however, we may venture to 
 infer, from finding the two classes under such a marked 
 diversity of dispensation, that creation must have been a 
 result, not of the ojJeration of mere law, wiiich would have 
 dealt after the same fashion with both, but a consequence 
 of the exercise of an elective will ; and that as amid im- 
 mense variety of eftbrt and fertility of invention there 
 are yet certain features of style, and a certain recurrence 
 of words and phrases, that enable us to identify a great 
 author, and to recognize a unity in his works that bespeaks 
 the unity of the producing mind, so ought these connect- 
 ing links and common features of widely-separated, and, 
 in the main, dissimilar creations, to teach us the salutary 
 lesson that the Author of all is One, and that, in the exer- 
 cise of his unrestricted sovereignty and of his infinite wis- 
 dom, he chooses and rejects according to his own good 
 pleasure. 
 
 From the plants of the swamps and forests of the Coal 
 Measures we j^ass on to its fauna, terrestrial and aquatic; 
 — a fauna winch, altliough less picturesque than its won- 
 drous flora, filled with all manner of strange shapes, seems 
 to have borne a corresponding character in uniting great 
 numeric development to a development comparatively litn- 
 ited in classes and orders; and with respect also to the 
 extreme antiqueness of many of its types. The prevailing 
 forms of both flora and fxuna belong equally to a fashion 
 that has perished and passed away. 
 
 It was held, up till a very recent period, that there had 
 existed no reptiles during the Carboniferous ages. Man 
 has been longer and more perseveringly engaged among 
 the Coal Measures than in any of the other formations ; 
 and, long ere geology existed as a science, what used to
 
 LECTURES ON GEOLOGY. 233 
 
 be termed its figured stones, — plants, shells and fishes, — 
 were, in consequence, well known to collectors, — a class 
 of people sent into the world to labor instinctively as pio- 
 neers in the physical sciences, without knowing why. I 
 have seen jirints of some of these figured stones of two 
 centuries' standing, and have succeeded in recognizing as 
 old acquaintance the Spirifers and Ferns which had sat for 
 their pictures to artists who knew nothing of either. Dur- 
 ing the last sixty years there have been many collections 
 made of the Carboniferous fossils, and many coal-fields 
 intelligently examined, but not a trace of the reptile de- 
 tected. It was not nntil Sir Charles Lyell's second visit 
 to the United States, five years ago, or rather not until 
 tbe publication of his second series of travels, three years 
 after, that it was known to European geologists that the 
 coal-fields of Pennsylvania, in the United States, had, like 
 the Trias ^ of the south of Scotland and of the sister king- 
 dom, their Cheirotherium, of, however, not only, as might 
 be anticipated, a diflferent species, but of even a different 
 genus, from that of the newer formation, though not less 
 decidedly reptilian in its character. And about the same 
 time, the remains of a reptile since known as the Arche- 
 gosaurus were found in a coal-field in Rhenish Bavaria. 
 The Archegosaurus seems to have been a strange-looking 
 creature, — half saurian, half batrachian, of comparatively 
 small size, with two staring eyes set close together in the 
 middle of a flat triangular skull, and furnished with limbs 
 terminating in distinct toes, but so slim and weak, "that 
 they could have served," says Von Meyer, " only for swim- 
 ming or creeping." ^ It is stated in the "Lake Superior" 
 
 1 Permians. — W. S. S. 
 
 2 The Archegosauri are related to the Batrachians and Sauroid fishes, 
 according to Owen, " Sihiria," new edition, p. 3a3. — W. S. S. 
 
 20*
 
 234 LECTURES ON GEOLOGY, 
 
 of Agassiz, that in a shallow expanse of the river into 
 which the lake falls, skirted by flat forest-covered banks, 
 and in which a long series of dreary mud-flats are covered 
 by from a few inches to a few feet of water, there occurs a 
 large gill-furnished salamander (Menobranchus), which the 
 Indians call the " walking fish," and which even to them is 
 a great curiosity. It swims wherever there is sufficient 
 depth of water, and creeps over the mud-flats where there 
 is not ; and, compared with the swift and powerful Lepi- 
 dosteus, a reptile-fish of the same stream, it is a stupid, 
 sluggish, inert creature, safe only in its uselessness and the 
 repulsiveness of its appearance. And, judging from the 
 feebleness of its limbs, and the shortness of its ribs, which 
 resemble, says Professor Owen, those of the half-lunged, 
 half-gilled Proteus, such seems to have been the chai-acter 
 of the Archegosaurus. Its contemporary, the American 
 Cheiratherium, as shown by its well-defined footprints, 
 must have been a stronger limbed and larger reptile, — a 
 batrachian heightened by a dash of the crocodile ; and, 
 though probably often a dweller in the water, the only 
 vestiges of it which remain show that it must have occa- 
 sionally stepped out of its river or lake, to take an airing 
 on the banks. Such is nearly the sum total of our knowl- 
 edge regarding the reptiles of the Carboniferous period.^ 
 Like mammals in the preceding Secondary ages, they 
 formed so inconspicuous a feature of the fauna of the 
 time, that until very recently it escaped notice, and so 
 was not recognized as a feature at all. So far as we yet 
 
 1 Lord Enniskillen possesses a fossil reptile allied to the Cheriotherium 
 from the Yorkshire coal-fields, the Parabatrachus Colei (Owen). A Laby- 
 rinthodont reptile, Baphates planiceps (Owen), has been found in the Nova 
 Scotia coal-fields. Also footmarks of sauroid reptiles have been discovered 
 in Scotland by Mr. Hugh Miller, and in the Forest of Dean by Mr. C 
 Bromby. — W. S. S.
 
 LECTURES ON GEOLOGY. 235 
 
 know, the great Secondary division, in which reptiles, both 
 in size and number, received their fullest development, had 
 but few genera of mammals, — a small pouched animal, 
 and small insectivorous ones : so far as we yet know, the 
 great Palaeozoic division, in which fishes, both in size and 
 number, received their fullest development, had but its 
 two genera of reptiles, both allied, apparently, to the hum- 
 ble batrachian order. The reigning dynasty of the one 
 period, though the mammal was present, was not that of 
 the mammal, but of the reptile : the reigning dynasty of 
 the other period, though the reptile was jDresent, was not 
 that of the reptile, but of the fish. 
 
 The fishes of the Coal Measures, in especial the reptile 
 fishes, were in truth very high types of their class. I have 
 already incidentally said, that with the humble Menobran- 
 chus or salamander of the great North American lakes 
 and their tributaries, there is a true reptile fish associated ; 
 — an order of creatures of which, so far as is yet known, 
 there exists in the present creation only a single genus. 
 It would almost seem as if the Lepidosteus had been 
 spared, amid the wreck of genera and sj^ecies, to serve us 
 as a key by which to unlock the marvels of the ichthyol- 
 ogy of those remote periods of geologic history appropri- 
 ated to the dynasty of the fish. This wonderful creature 
 is covered by scales, not of a horny substance, like those 
 of the fish common at our tables, but of solid bone, enam- 
 elled, like the human teeth, on their outer surfaces. Its 
 own teeth are planted in double rows of unequal size, the 
 larger being of a reptilian, the smaller of an ichthyic char- 
 acter; and the front teeth of the lower jaw are received, 
 as in the alligators, into sheath-like cavities in the upper 
 jaw, — another reptilian trait. Its vertebral column, wholly 
 unlike that of other fishes, each of whose vertebrae con-
 
 236 LECTURES ON GEOLOGY. 
 
 sists of a double cup, is formed of vertebrae one end of 
 which consists of a cup and another of a ball, — a charac- 
 teristic of the snake ; it possesses true gills, like all other 
 fishes ; but then it also possesses a peculiar form of cellular 
 air-bladder, opening into the throat by a glottis, which, 
 according to Agassiz, our highest authority, performs res- 
 piratory functions. The Lepidosteus, says Sir Charles 
 Lyell, in describing, in his second series of travels in the 
 United States, an individual which he had seen, in sailing 
 across Lake Solitary, leap like a trout or salmon over the 
 surface, in pursuit of its prey, — " the Lepidosteus, whose 
 hard shining scales are so strong and difficult to pierce 
 that it can scarcely be shot, can live longer out of the 
 water than any other fish of the United States, having a 
 large cellular swimming-bladder, which is said almost to 
 serve the purpose of a real lung." Further, we find Agas- 
 siz stating, in his " Lake Superior," that the Lepidosteus is 
 one of the swiftest of fishes, darting like an arrow through 
 the waters, and overcoming with facility even the rapids 
 of the Niagai'a. He adds further, that when at the latter 
 place, there was a living specimen caught for him, — the 
 first living specimen he had ever seen ; and that " to his 
 great delight, as well as to his utter astonishment, he saw 
 this fish moving its head upon its neck freely, right and 
 left, and upwards, as a saurian, and as no other fish in cre- 
 ation does." The true native Yankee has a mode wholly 
 his own, and somewhat redolent of the revolver and the 
 bowie-knife, of describing the peculiar immunities and 
 high standing of the Lepidosteus, or, as he fimiliarly terras 
 it, the gar-pike. " The gar-pike is," he says, " a happy 
 fellow, and beats all fish-creation : he can hurt everything, 
 and nothing can hurt him." And such is the living type
 
 LECTURES ON GEOLOGY. 237 
 
 of what was the prevailing and dominant family of the 
 fauna of the Coal Measures. 
 
 The great size and marvellous abundance of those rep- 
 tile fishes of the Carboniferous period may well excite 
 wonder. One ironstone band in the neighborhood of 
 Gilmerton has furnished by scores, during the last few 
 years, jaws of the Rhizodus Hihherti and its congeners, of 
 a mould so gigantic, that the rei^tile teeth which they 
 contain are many times more bulky than the teeth of the 
 largest crocodiles. Teeth and scales of the same genus 
 are also abundant among the limestones of Burdiehouse ; 
 — some of the teeth much worn, as if they had belonged 
 to very old individuals and some of the scales, which 
 were as largely imbricated as those of the haddock or 
 salmon, full five inches in diameter. The broken remains 
 of a Burdiehouse specimen now in the museum of the 
 Royal Society of Edinburgh are supposed by Agassiz to 
 have formed part of one of the largest of true fishes, — a 
 fish which might be appropriately described in the sub- 
 Hme language applied in Job to Leviathan. If the gar- 
 pike, a fish from three to four feet in length, can make 
 itself so formidable, from its great strength and activity, 
 and the excellence of its armor, that even the cattle and 
 horses that come to drink at the water's side are scarce 
 safe from its attacks, what must have been the character 
 of a fish of the same reptilian order, from thirty to forty 
 feet in length, furnished with teeth thrice larger than 
 those of the hugest alligator, and ten times larger than 
 those of the bulkiest Lepidosteus, and that was covered 
 from snout to tail with an impenetrable mail of enamelled 
 bone? "Canst thou play with Leviathan as with a bird? 
 Canst thou fill his skin with barbed irons, or his head with 
 fish-spears? Who can open the doors of his face? His
 
 238 LECTURES ON GEOLOGY. 
 
 teeth are terrible round about; bis scales are his pride, 
 shut up together as a close seal. In his neck remaineth 
 strength ; his heart is as firm as a stone, yea, as hard as a 
 piece of the nether millstone. The sword of him that 
 layeth at him cannot hold; the spear, the dart, nor the 
 habergeon. He esteemeth iron as straw, and brass as 
 rotten wood." 
 
 In the same waters as the formidable and gigantic 
 Holoptychean genus there lived a smaller but still very 
 formidable reptile fish, now known as the Megalichthys^ 
 — a fish whose body was covered w^ith enamelled quad- 
 rangular scales, and its head with enamelled plates, both 
 of so exquisite a polish, that they may still be occasionally 
 seen in the shale of a coalpit, catching the rays of the 
 sun, and reflecting them across the landscape, as is often 
 done by bits of highly-glazed earthernware or glass. It 
 was accompanied by another and still smaller, but very 
 handsome, and scarce less highly enamelled, genus of the 
 sauroid class, — the Diplopterus. And if, after the lapse 
 of so many ages, their armor still retains a polish so high, 
 we may be well assured that brightly must it have glit- 
 tered to the sun when the creatures leaped of old into the 
 air, like the Lepidosteus of Lake Solitary, after some 
 vagrant ephemera or wandering dragon-fly ; and brightly 
 must the reflected light have flashed into the dark recesses 
 of the old overhanging forest that rose thick and tangled 
 over the lake or river side. The other ichthyic contempo- 
 raries of these fishes wei'e very various in size and aspect. 
 About half their number belonged to the same ganoidal 
 or bone-covered order as the Holoptychius and Mega- 
 lichthys, and the other half to that placoidal order repre- 
 sented in our existing seas by the sharks and rays. The 
 lakes, rivers, and estuaries abounded, perhaps exclusively,
 
 LECTURES ON GEOLOGY. 239 
 
 in ganoids, sucli as the Palceoniscus, a small, handsome, 
 well-proportioned genus, containing several species, — the 
 Etcrynotus, a rather longer and deeper genus, formed 
 somewhat in the proportions of the modern bream, — and 
 the Acanthodes^ an elongated, spined, small-scaled genus, 
 formed in the proportions of the ling or conger eel. On 
 the other hand, the seas of the period, abundant also in 
 ganoids, were tenanted by numerous and obsolete families 
 of sharks, amply furnished both with razor-like teeth ia 
 their jaws for cutting, and millstone-like teeth on their 
 palates for crushing, — furnished, some of them, with 
 barbed stings, like the sting-rays, — and whose dorsal fins 
 were armed with elaborately carved spines. The only 
 representative of any of these genera of marine placoids 
 which still exists, is the Cestracion, or Port-Jackson shark, 
 a placoid of the southern hemisphere. 
 
 We know that over the rivers and lakes inhabited by 
 the ganoidal fishes of this period there fluttered several 
 species of iusects mounted on gauze wings, like the Ephe- 
 meridae of the present day. At least one of their number 
 must have been of considerable size ; a single wing pre- 
 served in ironstone, though not quite complete, is longer 
 than the anterior wing of one of our largest dragon-flies, 
 and about twice as broad ; and, as its longitudinal nervures 
 are crossed at nearly right angles by transverse ones, it 
 must have resembled, when attached to the living animal, 
 a piece of delicate net-work. In the woods, and among 
 the decaying trunks, there harbored at the same time 
 several species of snouted beetles, somewhat akin to the 
 diamond beetles of the tropics ; and with these, large, 
 many-eyed scoqiions. The marshes abounded in minute 
 crustaceans, of, however, a low order, that bore their gills 
 attached to their feet, and breathed the more freely the
 
 240 LECTURES ON GEOLOGY. 
 
 more merrily they danced ; and tlie seas contained the 
 last of the trilobites. I have ah-eady referred incidentally 
 to the shells. The fresh waters contained various forms 
 of Unio, somewhat similar to the pearl mussels of our 
 rivers ; the profounder depths of the sea had their brachi- 
 pods, — Spirifers and Producta; while molluscs of a higher 
 order — Orthoceratites, some of them of a gigantic size. 
 Nautilus, and Goniatite, — swam above. Corals of strange 
 shapes were abundant : there were several species of 
 Tubilipora, which more resembled the organ-pipe coral 
 than aught else that still exists; with great numbers of 
 a horn-shaped coi-al, Turbinolia, with its point turned 
 downwards, like that of a Cornucopia, and with an animal 
 somewhat akin to the sea-anemone, expanded, flower-like, 
 from its upper end. With these, too, there were grouped 
 delicately branched corals, mottled with circular cells ; and 
 minutely elegant Fenestrella, that seemed reduced editions 
 of the sea-fan. An antiquely-formed sea-urchin, whose 
 spines were themselves roughened with minute spines, as 
 the more delicate branches of a sweet brier are roughened 
 with thorns, crept slowly among these zoophytes by its 
 many cable-like tentacula ; while forests of Crinoidea 
 Avaved in the tide, and sent abroad their many arms from 
 the ledges overhead. Tliese forests of Crinoidea or 
 stone-lilies formed one of the leading characteristics of 
 the sea-bottoms of the period. We may conceive of them 
 as thickets of flexible-jointed stems rooted to the rocks, 
 and with a variously-formed star-fish fixed on the top of 
 each stem. Some of the stems were branched, some 
 simple ; in some the petals or rays were richly palmated ; 
 in others, plain and star-like; in some, what might be 
 deemed the calyx of the flower, but which was in reality 
 the stomach of the animal, was round and polished; in
 
 LECTURES ON GEOLOGY. 241 
 
 others, ornately carved into regular geometrical figures. 
 But, however various in their appearances, they were all 
 sedentary star-fishes, that, poised on their tall, cane-like 
 stems, sent abroad their arms into the waters of the old 
 Carboniferous ocean, in quest of food. The minute joints 
 of the stem, perforated in the middle by a circular passage, 
 and fretted by thick-set rays radiating from the centre, 
 seem to have attracted notice in an early age, and are 
 known in legendary lore as the beads of St. Cuthbert. 
 Dr. Mantell states that he has found quantities of these 
 perforated ossicula, which had been worn as ornaments, 
 in tumuli of the ancient Britons. And you will remem- 
 ber that in " Marmion," the nuns of St. Hilda, who lived 
 in a Liassic country, rich in Ammonites, had their stories 
 regarding the snakes which their sainted patroness had 
 changed into stone ; and that they were curious to know, 
 in turn, from the nuns of Lendisferne, who lived in a Car- 
 boniferous district, rich in encrinites, the true story of the 
 beads of St. Cuthbert. 
 
 " But fain St. Hilda's nuns would learn, 
 If on a rock bj' Lendisferne, 
 St. Cuthbert sits, and toils to frame 
 The sea-bom beads that bear his name. 
 Such tales had Whitby's fishers told, 
 And said they mij^ht his shape behold, 
 
 And hear his anvil sound. 
 
 A deadened clang, a huge dim form, 
 
 Seen but and heard, when gathering storm 
 
 And night were closing round." 
 
 Certainly, if he fabricated all the beads, he must have 
 been one of the busiest saints in the Calefidar. So amaz- 
 ingly abundant were the lily encrinites of the Carbon- 
 iferous period, that there are rocks in the neighborhood 
 
 21
 
 242 LECTURES ON GEOLOGY. 
 
 of Edinburgh of considerable thickness and great lateral 
 extent, composed almost exclusively of their remains. 
 
 The depth of the Carboniferous system has been well 
 described as enormous. Including the Mountain Lime- 
 stone, which is a marine deposit of the same period, and 
 which must be regarded as forming a member of the Coal 
 Measures, there are districts of England in which, as esti- 
 mated by Mantel), it has attained the vast thickness of 
 ten thousand feet. In our own immediate neighborhood 
 it does not, as estimated by a high authority, Mr. Charles 
 Maclaren, quite equal half that depth. Our Carboniferous 
 system, including the Roslyn and Calciferous sandstones, 
 he describes, in his " Geology of Fife and the Lothians," 
 as about four thousand five hundred feet in thickness, — a 
 thickness, however, which more than equals the height of 
 Ben Nevis over the level of the sea. That coal-basin 
 which extends along the flat, richly cultivated plain which 
 stretches from the south-eastern flanks of Arthur Seat 
 to the Garlton Hills in Haddingtonshire, considerably 
 exceeds three thousand feet in depth ; and, could it be 
 cleared out to the bottom of the Calciferous sandstones, 
 and divested of the hundred and seventy beds of which 
 it consists, as we have seen the deep hollow of the Com- 
 pensation Pond divested of its water, it would form by 
 far the profoundest valley in Scotland. Of the beds by 
 which it is occupied, it is estimated that about thirty are 
 coal, varying from several feet to but a few inches in thick- 
 ness ; and wo now know, that though some of the coal- 
 seams wei'c formed of drifted plants and trees deposited 
 in the sandy bottom of some great lake or inland sea, by 
 much the greater number are underlaced by bands of an 
 altered vegetable soil, thickly tx*aversed by roots ; and 
 that, as in the case of many of our larger mosses, the
 
 LECTURES ON GEOLOGY. 243 
 
 plants which entered into their composition must have 
 grown and decayed on the spot. And of course, when 
 the plants were growing, the stratum in which they occur, 
 though subsequently buried beneath plummet sound, or 
 at least thousands of feet, must have formed a portion 
 of the surface of the country either altogether subaerial, or, 
 if existing as a swamp, overlaid by a few inches of water. 
 We have evidence of nearly the same kind in the ripple- 
 markings, which are so abundant throughout all the shales 
 and sandstones of the Coal Measures, from top to bottom, 
 and which are never formed save where the water is shal- 
 low. Stratum after stratum in the whole ten thousand 
 feet included in the system, where it is mostly largely 
 developed, must have formed in succession the surface 
 either of the dry land or of shallow lakes or seas ; one 
 bed must have sunk ere the bed immediately over it could 
 have been deposited ; and thus, throughout an extended 
 series of ages, a process must have been taking place on 
 the face of the globe somewhat analogous to that which 
 takes place during a severe frost in those deeper lakes of 
 the country that never freeze, and in which the surfoce 
 stratum, in consequence of becoming heavier as it becomes 
 colder than the nether strata, is forever sinking, and thus 
 making way for other strata, that cease to be the surface 
 in turn. This sinking process, though persistent in the 
 main, must have been of an intermittent and irregular 
 kind. In some instances, forests seem to have grown on 
 vast platforms, that retained their level unchanged for 
 centuries, nay, thousands of years together ; in other cases 
 the submergence seems to have been sudden, and to such 
 a depth, that the sea rushed in and occupied wide areas 
 where the land had previously been, and this to so consid- 
 erable a depth, and for so extended a period, that the
 
 244 LECTURES ON GEOLOGY. 
 
 ridges of coral which formed, and the forests of Encrinites 
 which grew, in these suddenly hollowed seas, composed 
 thick beds of marine limestone, which we now find inter- 
 calated with coal-seams and lacustrine silts and shales. 
 There seem, t90, to have been occasional upward move- 
 ments on a small scale. The same area which had been 
 occupied first by a forest, and then by a lake or sea, came 
 to be occupied by a forest again ; and, though of course 
 mere deposition might have silted up the lake or sea to 
 the level of the water, it is not easy to conceive how, with- 
 out positive upheaval for at least a few feet, such surfaces 
 at the Avater-level should have become sufliciently consol- 
 idated for the production of gigantic Araucarians and 
 Pines. But the sinking condition was the general one ; 
 platform after platfonn disappeared, as century after cen- 
 tury rolled away, impressing upon them their character 
 as they passed ; and so the Coal Measures, where deepest 
 and most extensive, consist, from bottom to top, of these 
 buried platforms, ranged like the sheets of a work in the 
 course of printing, that, after being stamped by the press- 
 man, are then placed horizontally over one another in a 
 pile. Another remarkable circumstance, which seems a 
 direct result of the same physical conditions of our planet 
 as those ever-recurring subsidences, is the vast horizontal 
 extent and persistency of these platforms. The Appalla- 
 chian Coal formation in the United States has been traced 
 by Professor Henry Rogers over an area considerably 
 more extensive than that of all Great Britain ; and yet 
 there are some of its beds that seem continuous through- 
 out. The great Pittsburg coal-seam of this field — a 
 seam wonderfully uniform in its thickness, of from eight 
 to twelve feet — must have once covei-ed a surface of 
 ninety thousand square miles. And this characteristic of
 
 LECTURES ON GEOLOGY. 245 
 
 persistency, united to a great extent, in the various plat- 
 forms of the Coal Measures, and of ever-recurring sub- 
 sidence and depression, which accumulated one surface 
 platform over another for hundreds and thousands of feet, 
 belongs, I am compelled to hold, to a condition of things 
 no longer witnessed on the face of the globe. The earth 
 has still its morasses, its deltas, its dismal swamps ; it has 
 still, too, its sudden subsidences of surface, by w^hich tracts 
 of forest have been laid under water; but molasses and 
 deltas cover only very limited tracts, and sudden sub- 
 sidences are at once very excej^tional and merely local 
 occurrences. Subsidence during the Carboniferous ages, 
 though interrupted by occasional periods of rest, and occa- 
 sional paroxysms of upheaval, seems, on the contrary, to 
 have been one of the fixed and calcvilable processes of 
 nature ; and, from apparently the same cause, persistent 
 swamps, and accumulations of vegetable matter, that equal- 
 led continents in their extent, formed one of the common 
 and ordinary features of the time. 
 
 My subject is one on which great diversity of opinion 
 may and does prevail. But, while entertaining a thorough 
 respect for the judgment and the high scientific acquire- 
 ments of geologists who hold that the earth existed at 
 this early period in the same physical conditions as it does 
 now, I must persist in believing that these conditions 
 were in one important respect essentially different ; I must 
 persist in believing that our planet was greatly more plastic 
 and yielding than in these later times ; and that the mol- 
 ten abyss from which all the Plutonic rocks were derived, 
 — that abyss to whose existence the earthquakes of the 
 historic period and the recent volcanoes so significantly 
 testify, — was enveloped by a crust comparatively thin. 
 Like the thin ice of the earlier winter frosts, that yields 
 
 21*
 
 246 LECTURES ON GEOLOGY. 
 
 under the too adventurous skater, it could not support 
 great weights, — table-lands such as now exist, or moun- 
 tain chains ; and hence, apj^arently, the existence of vast 
 swampy plains nearly level with the sea, and ever-recur- 
 ring periods of subsidence, wherever a course of deposi- 
 tion had overloaded the surface. The yet further fact, 
 that as we ascend into the middle and earlier Palaeozoic 
 periods, the traces of land become less and less frequent, 
 until at length scarce a vestige of a terrestrial plant or 
 animal occurs in entire formations, seems charged with a 
 corroborative evidence. I shall not say that in these 
 primeval periods 
 
 " A shoreless ocean tumbled round the globe," 
 
 for the terrestrial plants of the Silurians show that land 
 existed in even the earliest ages in which, so far as the 
 geologist knows, vitality was associated with matter ; but 
 it would seem that only a few insulated parts of the 
 earth's surface had got their heads above water at the 
 time. The thin and partially consolidated crust could not 
 bear the load of great continents; nor were the "moun- 
 tains yet settled, nor the hills brought forth." It would 
 seem that not until the Cai'boniferous ages did there exist 
 a period in which the slowly-ripening planet could exhibit 
 any very considerable breadth of land ; and even then it 
 seems to have been a land consisting of immense flats, 
 unvaried, mayhap, by a single hill, in which dreary swamps, 
 inhabited by doleful creatures, spread out on every hand 
 for hundreds and thousands of miles, and a gigantic and 
 monstrous vegetation formed, as I have shown, the only 
 prominent featm-e of the scenery. Burnett held that the 
 earth, previous to the Flood, was one vast plain, without 
 hill or valley, and that Paradise itself, like the hlomen
 
 LECTURES ON GEOLOGY. 247 
 
 garten of a wealthy Dutch burgomaster, was curiously 
 laid out upon a flat. We would all greatly prefer the 
 Paradise of Milton : 
 
 " A happy rural seat of various views, 
 Where lawns and level downs, whitened with flocks 
 Grazing the tender herb, were interposed 
 With palmy hillocks and irrageous vales 
 Luxuriant; and where murmuring waters fell 
 Do^vn the steep hills dispersed, or in blue lakes 
 Embraced the fringed banks, with myrtle crowned." 
 
 It was during the times of the Coal Measures that Burnett 
 would have found his idea of a perfect earth most nearly 
 realized, in at least general outline ; but even he would 
 scarce have deemed it a paradise. Its lands were lands in 
 which, according to the Prophet, there " could no man 
 have dwelt, nor son of man passed through." From some 
 tall tree-top the eye would have wandered, without rest- 
 ing-place, over a wilderness of rank, unwholesome morass, 
 dank with a sombre vegetation, that stretched on and 
 away from the foreground to the distant horizon, and for 
 hundreds and hundreds of leagues beyond ; the woods 
 themselves, tangled, and dank, and brown, would, accord- 
 ing to the poet, have " breathed a creeping horror o'er the 
 frame;" the surface, even where most consolidated, would 
 have exhibited its frequent ague-fits and earth-waves; and, 
 after some mightier earthquake had billowed the landscape, 
 dashing together the crests of tall trees and gigantic 
 shrubs, there would be a roar, as of many waters, heard 
 from the distant outskirts of the scene, and one long wall 
 of breakers seen stretching along the line where earth and 
 sky meet, — stretching inwards, and travelling onwards 
 with yet louder and louder roar, — Calamite and Uloden- 
 dron, Sigillaria and Tree-fern, disappearing amid the foam.
 
 248 LECTURES ON GEOLOGY. 
 
 — until at length all would be submerged, and only here 
 and there a few Araucalrian tops seen over a sea without 
 visible shore. Such was the character, and such were the 
 revolutions, of the land of the Carboniferous era, — a land 
 that seems to have been called into being less for the sake 
 of its own existence than for that of the existences of the 
 future. 
 
 X
 
 LECTURE SIXTH. 
 
 Remote Antiquity of the Old Red Sandstone — Suggestive of the vast Tracts of 
 Time with which the Geologist has to deal — Its great Depth and Extent in 
 Scotland and England — Peculiarity of its Scenery — Reflection on first dis- 
 covering the Outline of a Fragment of the Asterolepis traced on one of its 
 Rocks — Consists of Three Distinct Formations — Their Vegetable Organisms 
 — The Caithness Flagstones, how formed — The Fauna of the Old Red Sand- 
 stone — The Pterichthys of the Upper or Newest Formation — The Cephalaspis 
 of the Lower Formation — The Middle Formation the most abundant in Or- 
 ganic Remains — Destruction of Animal Life in the Formation sudden and 
 violent — The Asterolepis and Coccosteus — The Silurian the Oldest of the 
 Geologic Systems —That in which Animal and Vegetable Life had their earliest 
 beginnings — The Theologians and Geologists on the Antiquity of the Globe — 
 Extent of the Silurian System in Scotland — The Classic Scenery of the Coun- 
 try situated on it — Comparatively Poor in Animal and Vegetable Organisms — 
 The Unfossiliferous Primary Rocks of Scotland — Its Highland Scenery formed 
 of them — Description of Glencoe — Other Highland Scenery glanced at — 
 Probable Depth of the Primary Stratified Rocks of Scotland — How deposited 
 — Speculations of Philosophers regarding the Processes to which the Earth 
 owes its present Form — The Author's Views on the subject. 
 
 I INCIDENTALLY mentioned, when describing the Oolitic 
 productions of our country, that the shrubs and trees of 
 this Secondary period grew, on what is now the east coast 
 of Sutherland, in a soil which rested over rocks of Old 
 Red Sandstone, and was composed mainly, like that of the 
 county of Caithness in the present day, of the broken de- 
 bris of this ancient system. We detect fragments of the 
 Old Red flagstones still fast jammed among the petrified 
 roots of old Oolitic trees ; we find their water-rolled peb- 
 bles existing as a breccia, mixed up with the bones of huge 
 Oolitic reptiles and the shells of extinct Oolitic molluscs j
 
 250 LECTURES ON GEOLOGY. 
 
 we even find some of its rounded masses incrusted over 
 with the corals of the Oolite : the masses had existed in 
 that remote age of the world as the same gray indurated 
 blocks of stone that we find them now ; and busy Mad- 
 reporites, — Isastraea and Thamnastrsea, — whose species 
 have long since perished, built up their stony cells on the 
 solid foundations which the masses furnished. Nay, within 
 the close compressed folds of these flagstones lay their 
 many various fossils, — glittering scale, and sharp spine, 
 and cerebral buckler, — in exactly the same state of keep- 
 ing as now ; and had there been a geologist to take ham- 
 mer in hand in that Oolitic period, when the spikes of the 
 Pinites JEiggensis were green upon the living tree, and the 
 Equisetiim columnare waved its tall head to the breeze, 
 he would have found in these stones the organisms of a 
 time that would have seemed as remote then as it does in 
 the present late age of the world. We may well apply to 
 this incalculably ancient Old Red system what Words- 
 worth says of his old Cumberland beggar — 
 
 " Whom from his childhood had he known, that then 
 He was so old, he seemed not older now." 
 
 This glimpse, through the medium of the high antiquity 
 of the Oolite, of an antiquity vastly higher still, — that of 
 the Old Red Sandstone, — may well impress us with the 
 enormous extent of those tracts in time with which the 
 geological historian is called on to deal. There are some 
 of the lesser planets that seem to the naked eye quite as 
 distant as many of those fixed stars whose parallax the 
 astronomer has failed to ascertain ; but when they come 
 into a state of juxtaposition, and the moveless star is seen 
 dimly through the atmosphere of the moving planet, we 
 are taught how enormous must be those tracts of space
 
 LECTURES ON GEOLOGY. 251 
 
 which intervene between them, and keep them apart. 
 And it is thus with the periods of the geologist. Even 
 the comparatively near are so distant, that the remote 
 seem scarce more so ; but the dead and stony antiquity of 
 one system, seen as if through the living nature of another, 
 enables us, in at least some degree, to appreciate the vast- 
 ness of those cycles by which they were separated. It is 
 farther interesting, too, thus to find one antiquity curiously 
 inlaid, as it were, in another. We feel as if, amid the an- 
 cient relics of a Pompeii or a Herculaneum, we had stum- 
 bled on the cabinet of some Roman antiquary, filled with 
 bronze and granite memorials of the first Pharaohs, or of 
 the old hunter king who founded Nineveh; — things that 
 in times which we now deem ancient had been treasured 
 up as already grown venerably old. 
 
 The Old Red Sandstone underlies the Coal Measures, 
 and is, in Scotland at least, still more largely developed 
 than these, both in depth and lateral extent. In Caithness 
 and Orkney, one of the three great formations of which it 
 consists has attained to a thickness that equals the height 
 of our highest hills over the sea.^ The depth of the entire 
 system in England has been estimated by Sir Roderick 
 Murchison at ten thousand feet ; and as these ten thousand 
 feet include three formations so distinct in their groups of 
 animal life that not a sjjecies of fish has been found com- 
 mon to both higher and lower, it must represent in the 
 history of the globe an enormously protracted period of 
 time. 
 
 The scenery of the Old Red Sandstone we find much 
 affected to the south of the Grampians, like that of the 
 Coal Measures, by the presence of the trap rocks; but in 
 
 1 The Caithness flag-stones and their ichthyolites constitute, according 
 to Sir R. Murchison, the central portion of the Old Red group. — W. S. S.
 
 252 LECTURES ON GEOLOGY. 
 
 the north, where there is no trap, it bears a character 
 decidedly its own. It is remarkable for rectilinear ridges, 
 elongated for miles, that, when they occur in semi-Highland 
 districts, where the primary rocks have been heaved into 
 wave-like hills, or ascend into boldly-contoured mountains, 
 constitute a feature noticeable for the contrast which it 
 forms to all the other features of the scene. In approach- 
 ing the eastern coast of Caithness from the south, the 
 voyager first sees a mountain country, — the land piled up 
 stern and high, — the undulations bold and abrupt. He is 
 looking on the Highlands of Sutherlandshire. All at once, 
 however, the aspect of the landscape changes ; — the bro- 
 ken and wavy line suddenly descends to a comparatively 
 low level, and, wholly altering its character, stretches away 
 to the north, straight as a tightened cord, or as if described 
 by a ruler. Caithness, thus seen in profile, reminds one of 
 a long, thin proboscis, or mesmerized arm, stretched stiffly 
 out from the Highlands to the distant Orkneys. In sailing 
 upwards along the Moray Frith, the line which defines 
 seawards the plain of Easter Ross, from the Hill of Nigg 
 to the low rocky promontory of Tarbat, topped by its 
 lighthouse, presents nearly the same rectilinear character. 
 Another long straight line which meets the eye on enter- 
 ing the bay of Cromarty, stretches westwards from the hill 
 of granitic gneiss immediately over the town, and runs for 
 many miles into the interior, along the bleak ridge of the 
 Black Isle. Yet another rectilinear line may be seen run- 
 ning on the south side of the Moray Frith, from beyond 
 the Moor of Culloden, which it includes, to the eastern 
 end of Loch Ness. And in all these instances the rectili- 
 near ridges are composed of Old Red Sandstone. On 
 some localities on the seaboard of the country, the system 
 is much traversed by friths and bays, and what in Caith-
 
 LECTURES OX GEOLOGY. 253 
 
 bess and Orkney are termed goes^ — narrow inlets in the 
 line of faults, along which the waves find straight passage 
 far into the interior. From the Hill of Nigg, the centre of 
 an Old Red Sandstone district, the eye at once commands 
 three noble friths, all scooped out of the deposit, — the 
 Frith of Cromarty, the Dornoch Frith, and the upper 
 reaches of the Moray Frith. It commands, too, what is 
 scarce less a feature of the Old Red system, — the rich 
 corn-bearing plains of Moray and of Easter Ross ; and from 
 the union which the prospect exhibits of two elements dis- 
 sociated elsewhere in the country, — the rich softness of a 
 Lowland scene, with numerous arms of the sea, character- 
 istic elsewhere, as on the western coast, of a Highland one, 
 — it forms a landscape unique among the landscapes of 
 Scotland. But perhaps the most striking scenic peculiari- 
 ties of the Old Red Sandstone are to be found in its rock- 
 pieces. The Old Man of Hoy, with its mural rampart of 
 precipices, not unfurnished with turret and tower, and wide 
 yawning portals, and that rise a thousand feet over the 
 waves ; the tall stacks of Cannisbay, ornately Gothic in 
 their style of ornament, with the dizzy chasms of the 
 neighboring headland, in which the tides of the Pentland 
 Frith forever eddy and boil, and the surf forever roars ; 
 and the strangely fractured precipices of Holburn Head, 
 where, through dark crevice and giddy chasm, the gleam 
 of the sun may be seen reflected far below on the gi-een 
 depths of the sea, and, venerable and gray, like some vast 
 cathedral, a dissevered fragment of the coast descried rising 
 beyond, — are all rock-scenes of the Old Red Sandstone. 
 When I last stood on the heights of Holburn, there was a 
 heavy surf toiling far below along the base of the over- 
 hanging wall of clifi" which lines the coast; and deep under 
 my feet I could hear a muffled roaring amid the long, cor- 
 
 22
 
 254 LECTURES ON GEOLOGY. 
 
 ridor-like caves into which the headland is hollowed, and 
 which, opening to the light and air far inland, by narrow 
 vents and chasms, send np at such seasons, high over the 
 blighted sward, clouds of impalpable sjjray, that resemble 
 the smoke of great chimneys. As I jDeered into one of 
 these profound gulfs, and dimly marked, hundreds of feet 
 below, the upward dash of the foam, gray in the gloom ; 
 as I looked, and experienced, with the gaze, that mingled 
 emotion natural amid such scenes which Burke so well 
 analyzes as a consciousness of great expansiveness and 
 dimension, associated with a sense of danger, — my eye 
 caught, on the verge of the precipice, the outline of part 
 of an old reptile fish traced on the rock. It was the cra- 
 nial buckler of one of the hugest ganoids of the Old Red 
 Sandstone, — the Asterolepis. And there it lay, as it had 
 been deposited, far back in the bypast eternity, at the bot- 
 tom of a muddy sea. But the mud existed now as a dense 
 gray rock, hard as iron ; and what had been the bottom of 
 a Palaeozoic sea had become the edge of a dizzy preciijice, 
 elevated more than a hundred yards over the surf The 
 world must have been a very different world, I said, when 
 that creature lived, from what it is now. There could have 
 been no such precipices then. A few flat islands comprised, 
 in all probability, the whole dry land of the globe ; and 
 that emotion of which I have just been conscious, is it not 
 something new in creation also? The deep gloom of these 
 perilous gulfs, these incessant roarings, these dizzy preci- 
 pices, the sublime roll of these huge waves, — are they not 
 associated in my mind with a certain dim idea of danger, 
 — a feeling of incipient teiTor, which, in all God's creation, 
 man, and man only, is organized to experience ? Is it not 
 an emotion which neither the inferior animals on the one 
 hand, nor the higher sj^iritual existences on the other, can
 
 LECTURES ON GEOLOGY. 255 
 
 in the least feel, — an emotion dependent on the union of 
 a living soul with a fragile body of clay, easily broken ? 
 
 The Old Red Sandstone consists, as I have said, of three 
 great formations, furnished each, in Scotland at least, with 
 its peculiar group of fossils. In the upper division — that 
 which rests immediately under the Carboniferous system 
 — a few straggling plants of the Coal Measures have been 
 occasionally found; but, so far as I know, no 2:>lant jieculiar 
 to itself. In the middle {loioer) division we find traces of 
 a peculiar but very meagre flora. I detected about ten 
 years ago, among the gray micaceous sandstones of For- 
 farshire, a fucoid furnished with a thick, squat stem, that 
 branches into numerous divergent leaflets or fronds of a 
 slim, grass-like form, and which, as a whole, somewhat 
 resembles the scourge of cords attached to a handle with 
 which a boy whips his top. And Professor Fleming de- 
 scribes a still more remarkable vegetable organism of the 
 same formation, which, to employ his own well-selected 
 words, "occuis in the form of cii'cular flat patches, com- 
 posed each of numerous smaller contiguous circular pieces, 
 altogether not unlike what might be expected to result 
 from a compi-essed berry, such as the bramble or rasp." ^ 
 •In the lowest [middle) division of the Old Red traces of 
 land plants become very rare. Many years ago, at Crom- 
 arty, I detected, in one of its oldest fossiliferous beds, a 
 fragment of a cone-bearing tree, remarkable as being the 
 oldest piece of wood ever found, that, when subjected to 
 the microscope, exhibits the true ligneous structure ; and 
 I possess a small specimen from Skaill, in the mainland of 
 Orkney, also detected in one of the lower beds, which 
 
 ^ Parka decipiens. See "Testimony of the Rocks," latest edition. For 
 notice of a Lepidodendron occurring in the Forfarshire sandstone, see like, 
 wise " Testimony of the Rocks," page 445 — 7. — L. M.
 
 256 LECTURES ON GEOLOGY. 
 
 formed, apparently, a portion of some nameless fern ; but 
 the other vegetable remains of the lower {iniddle) division, 
 though sufficiently abundant in some localities to give a 
 fissile chai'acter to the rock in which they occur, are, with 
 one doubtful exception, all marine. They were the weeds 
 of a widely extended sea, in which land was at once very 
 unfrequent and of very limited extent. In the neighbor- 
 hood of Thurso my attention has been attracted for sev- 
 eral years past by a curious apjDcarance among the flag- 
 stones of the district, — there enormously developed, — 
 which I am disposed to regard as indications of the exist- 
 ence of vast mud flats of the Old Red Sandstone, that 
 occasionally showed their surfaces above water for perhaps 
 weeks and months at a time, but which were, in every 
 instance, submerged ere they acquired coverings of terres- 
 trial vegetation. The flagstones, now known very exten- 
 sively over Europe as the Caithness flag of commerce, 
 must have been deposited at the bottom of a shallow sea, 
 in the form of beds of arenaceous mud, largely charged 
 with organic matter. They abound in minute ripple- 
 markings, which could have been formed only a few feet, 
 or at most a few fathoms, under the surface ; and between 
 these ripjiled bands, for a series of beds together, there 
 occur bands which had been evidently subjected to a dry- 
 ing process, so that, as happens with the bottom of a 
 muddy pool laid dry during the summer droughts, they 
 cracked into irregularly polygonal divisions ; and as, when 
 again submerged, a sudden deposition filled up the cracks, 
 we can still trace these marks of desiccation as distinctly 
 in the stone as if they had been made by the sun of the 
 previous week. Hall, of Leicester, spoke, in one of his 
 illustrations, of "a continent of mud;" and it would seem 
 that in the earlier ages of the Old Red Sandstone, conti
 
 LECTURES ON GEOLOGY. 257 
 
 nents of mud were not mere figures of speech, but that, 
 over dark-hued and shallow seas, mud-banks of vast extent 
 occasionally raised their flat dingy backs, and remained 
 hardening in the hot sun until their oozy surfaces had 
 cracked and warped, and become hard as the sun-baked 
 brick of eastern countries ; and that then, ere the seeds 
 of terrestrial plants, floated from some distant island, or 
 wafted in the air, had found time to strike root into the 
 crevices of the soil, some of the frequent earth-tremors 
 of the age shook the flat expanse under the water out of 
 which it had arisen, and the waves rippled over it as 
 before. The features of a scene so tame and unattractive 
 — features which none of the poets, save perhaps the 
 truthful Crabbe, would have ventured to portray — will 
 not strike you as very worthy of preservation. There is 
 certainly not much to excite or gratify the fancy in a scene 
 of wide yet shallow seas, here and there darkened by for- 
 ests of algae, and here and there cumbered by archipelagos 
 of flat, verdureless islands of mud that harden in the sun ; 
 but, regarded as embryo and rudimentary land, even these 
 mud-banks may be found to possess their modicum of 
 interest. And we know that in the shallows of that 
 muddy sea, the Creator wrought with all his wonted wis- 
 dom and inexhaustible fertility of resource, in the produc- 
 tion of a dynasty of fishes of very extraordinary form, but 
 high type, and which manifested exquisite faculties of 
 adaptation to the circumstances in which they were placed. 
 In glancing at the fauna of the Old Red Sandstone, let 
 us imagine three great platforms from which the sea has 
 just retired, leaving them strewn over with its spoils, — 
 chiefly fishes. These platforms represent the three great 
 periods of the system ; and in each do we find the group 
 specifically, and in several instances generically, distinct. 
 
 22*
 
 258 LECTURES ON GEOLOGY. 
 
 In the upper or newer platform — that immediately under 
 the Coal Measures — there occur several species of Holoj)- 
 tychius, all of them of smaller dimensions than the giant 
 of the Carboniferous system, but, in proportion to their 
 bulk and size, even 7nore strongly armed. With the Ho- 
 loptychius there was associated a fish of the same Cela- 
 canth family, the Bathriolepis, and sevei-al curious fishes 
 of what is known as the Dipterian family, such as the 
 Stagonolepis^ and Glyptolepis. It contains also at least 
 three species of Pterichthys. One of these, the Pterich- 
 thys mc(jor, which occurs in the upper sandstones of 
 Moray, is of greater size than any of the others its con- 
 temporaries, or than any of the older species ; as if, in at 
 least point of bulk, the creature received its fullest devel- 
 opment just when on the eve of passing away.^ This 
 strange Pterichthyan genus first appears at the base of the 
 Old Red Sandstone, and disappears with its upper beds. 
 It is peculiarly and characteristically the distinctive organ- 
 ism of the system, for in no other system does it occur ; 
 and it has a yet further claim on our notice here, from the 
 extreme singularity of its construction. "It is impossi- 
 ble," says Agassiz, in his great work on fossil fishes, " it 
 is impossible to find anything more eccentric in the whole 
 
 1 The Stagonolepis is now under examination as to whether it is to be 
 ranked as tish or reptile. Sir R. Murchisou mentions this in his last 
 address to the Leeds British Association, as still undetermined. — L. M. 
 
 2 Associated with this large Pterichthys are now found not only the 
 Telerpeton Elginense, a small tortoise, but footprints of larger reptiles, 
 some only of greater size than the Telerpeton, others considered to ap- 
 proach more nearly in bulk and conformation to some of those of the 
 succeeding eras. When I lately visited the Museum at Elgin, I was grat- 
 ified by seeing sandstone slabs bearing the traces of each of these ; but I 
 was told that the best specimens had been sent to London for examination. 
 It is probable that they will have been lawfully named and "surnamed by 
 the savaiUs ere the next edition of this work is ready for the press. — L. M.
 
 LECTURES ON GEOLOGY. 259 
 
 creation than this genus. The same astonishment which 
 Cuvier felt on examining for the first time the Plesio- 
 sauri, I myself experienced when Mr. Hugh Miller, the 
 original discoverer of these fossils, showed me the speci- 
 mens which he had collected from the Old Red Sandstone 
 of Cromarty." And we find Humboldt refemng, in his 
 "Cosmos," to this strange Pterichthyan genus in nearly 
 the same terms. This, I suspect, is no place for strict ana- 
 tomical demonstration ; and so, instead of elaborately 
 describing the Pterichthys, I shall merely attempt sketch- 
 ing its general outlines by the aid of a few simple illus- 
 trations. When, in laying open the rock in which it lies, 
 the under part is pi'esented, as usually happens, we are 
 struck with its resemblance to a human figure, with the 
 arms expanded, as in the act of swimming, and the legs 
 transformed, as in the ordinary figures of the mermaid, 
 into a tapering tail. On further examination, we ascertain 
 that the creature was cased in a complete armature of 
 solid bone, but that the armor was of different construc- 
 tion over the different parts. The head was covered by a 
 strong helmet, perforated in front by two circular holes, 
 through which the eyes looked out. The chest and back 
 were protected by a curiously constructed cuirass, formed 
 of plates ; and the tail sheathed in a flexible mail of osse- 
 ous scales. The arms, which were also covered with 
 plates, were articulated rather to the lower part of the 
 head than to the shoulders; and this by what at first 
 appears to be simply a ball-and-socket joint, Hke that of 
 the human thigh, but which, on further examination, proves 
 to be of a more complex character, as we find a pin-like 
 protuberance from the socket finding, in turn, a socket in 
 the ball. The abdomen of the creature was flat ; the dor- 
 sal portions strongly arched ; and not in our Gothic roofs,
 
 260 LECTURES ON GEOLOGY. 
 
 constructed on strictly mathematical principles, do we 
 discover more admirable contrivances for combining in the 
 greatest degree lightness with strength, than in the arch 
 of osseous plates which protected the Pterichthys. Nay, 
 we find in it the two leading peculiaiities of the Gothic 
 roof anticipated, — the contrivance of a series of ribs that 
 radiate from certain centres, and the contrivance of the 
 groin. The helmet was united to the cuirass by a curious 
 and yet very simple joining, that united the principle of 
 the dovetail of the carpenter to that of the keystone of 
 the architect. Farther, the creature, with its inflexible 
 cuirass and its flexible tail, and with its two arms, that 
 combined the broad blade of the paddle with the sharp 
 point of the spear, might be regarded, when in motion, 
 as a little subaqueous boat, mounted on two oars and a 
 scull. And such was the Pterichthys, — the characteristic 
 organism of the Old Red Sandstone. I may remark, in 
 connection with this fish, — a remark, however, which 
 bears equally on all its ganoidal contemporaries, — that 
 the development of its dermal or skin-skeleton, compared 
 with that of its internal one, was singularly great. In the 
 present creation, with but a few exceptions, such as the 
 Pangolin and Armadilla among quadrupeds, the crocodiles 
 and tortoises among reptiles, and the Lepidosteus and 
 Polyopterus among fishes, the dermal skeleton is but very 
 slenderly represented. In our own species, for instance, 
 it is represented by but the teeth, the hair, and the nails ; 
 and were there no other portions of us to survive in the 
 fossil state, each of the male animals among us would be 
 represented by but ten toe and ten finger nails, one set of 
 teeth, a periwig, and a pair of whiskers. But so complete, 
 on the other hand, was the development of the dermal 
 skeleton among the fishes of the Old Red Sandstone, that,
 
 LECTURES ON GEOLOGY. 261 
 
 though in many instances no other parts of them survive, 
 we find their outlines complete in the rock from head to 
 tail. Dermal plates of enamelled bone represent the head ; 
 dermal scales, also of enamelled bone, lie ranged side 
 by side, like tiles on a roof, in the lines in which they 
 originally covered the body; and thickly-set enamelled 
 rays of bone indicate the place and outline of the fins. 
 As a set-off, however, against this great development of 
 dermal skeleton in the ganoids of the Old Red Sandstone, 
 their internal skeletons were exceedingly slight, and in 
 whole families entirely cartilaginous. 
 
 The middle {loicer) platform of the Old Red Sandstone 
 has for its characteristic organism the Cephalaspis, or 
 Buckler-head, — a curiously formed, bone-covered fish, 
 with a thin triangular body, and crescent-shaped head, 
 somewhat resembling in outline a shoemaker's cutting- 
 knife. It had for its contemporaries several fishes armed 
 with dorsal spines, of which only the spines remain, and 
 of a gigantic Crustacean, akin, as shown by some of its 
 plates, to our existing lobsters, but which in some speci- 
 mens must have exceeded four feet in length. 
 
 It is, however, on the lower (iniddle) platform of the 
 system that we find its organic remains at once most 
 abundant and most characteristic. The flagstones of 
 Caithness and Orkney, and the nodule-bearing beds of 
 Ross, Cromarty, and Moray, contain more fossil fish than 
 all the other formations of not only Scotland, but of Great 
 Britain, fi-om the Tertiary deposits down to the Mountain 
 Limestone. There are strata in which they lie as thickly 
 as herrings on our better fishing banks in autumn, when 
 the fisherman's harvest is at its best ; and, strange to say, 
 not unfrequently do the fish of a whole platform give evi- 
 dence, both in their state of keeping and in theii' con-
 
 262 LECTURES ON GEOLOGY. 
 
 toi'ted attitude, that they all died at once, and died by vio- 
 lent death. We see them still presenting over wide ai"eas 
 the stiff curved outline — a result of the unequal contrac- 
 tion of the muscles — which, as in the case of recently 
 netted herrings, marks that dissolution had been sudden. 
 We find, too, that their remains did not suffer from the 
 predatory attacks of other fishes: it would seem as if 
 all the finny inhabitants of wide tracts of sea had been 
 at once cast dead to the bottom, so that not an individual 
 survived, to prey upon the remains of his deceased neigh- 
 bors. It was the first remark of Agassiz, when introduced 
 to a collection of fossil-fish from Orkney, — "All these fish 
 died by violent death," — a remark which he again and 
 yet again repeated when introduced to the Old Red ich- 
 thyolites of Cromarty and Morary. We have already 
 seen that the oldest plant-covered land of which the geol- 
 ogist finds distinct and certain trace in this country was a 
 land subject to incessant fluctuations of level, and to sud- 
 den and disastrous invasions of the sea; and that, though 
 suited for the production of a rank and luxuriant flora, 
 whose numerous denizens lived without consciousness and 
 died without suffering, or for animals fitted to enjoy the 
 present without thought or fear of the future, and to whom 
 life, so long as they lived, was pleasure, and death merely 
 a ceasing to be, we conclude that it could have been no 
 fitting home for creatures of a higher order, whosie nature 
 it is to look before and behind tliem, — before them with 
 hope or with fear, behind them with satisfaction or regret. 
 And these strange platforms of sudden death — of no rare 
 occurrence in the marine depths of the Old Red Sand- 
 stone — show that the sea in these early times was not less 
 subject to disastrous catastrophe than the land, — that that 
 order of nature which we now terra its fixed order, and
 
 LECTURES ON GEOLOGY. 263 
 
 on whose permanency oar minds have been framed to cal- 
 culate, was, if I may venture the expression, enacted, but 
 not enforced, and so the breaches of it were scarce more 
 exceptional than the observance, — that life, greatly more 
 emphatically than now, was the least certain of all things, 
 — and that both in sea and on the land the young and 
 immature earth, like an inexperienced and careless nurse, 
 was ever and anon overlaying and smothering its off- 
 spring. 
 
 Among the various ichthyic families and genera of 
 the Lower and Middle Old Red Sandstone, — Acanths, 
 Dipterians, Coelacanths, and Cephalaspians, — I shall refer 
 to only two, and that in but a few brief words ; the one 
 remarkable for its great size, the other for its extraordinary 
 organization. The Astei'olepis seems to have been one of 
 at once the earliest and bulkiest of the ganoids. Cranial 
 bucklers of this creature have been found in the flagstones 
 of Caithness large enough to cover the front skull of an 
 elephant, and strong enough to have sent back a musket- 
 bullet as if from a stone wall. The Asterolepis must have 
 at least equalled in size the largest alligators ; and there 
 were several j^oints in which it must have resembled that 
 genus of reptiles. Its head was covered with strong osse- 
 ous plates, ornately fretted by star-like markings, and its 
 body by closely imbricated and delicately-carved osseous 
 scales. But it is chiefly in its jaws that we trace a rep- 
 tilian relationship to the alligators. The alligators among 
 existing reptiles, and the Lepidostei among existing rep- 
 tile-fishes, are remarkable for a peculiar organization of 
 tooth and maxillary, through which certain long teeth in 
 the anterior part of the nether jaw are received into cer- 
 tain scabbard-like hollows in the anterior part of the 
 upper jaw. The hollows receive the teeth when the
 
 264 LECTURES ON GEOLOGY. 
 
 mouth is shut, as the scabbard receives the sword. Now, 
 in the Asterolepis this reptilian j^eculiarity was not re- 
 stricted to a small group of the anterior teeth, but per- 
 vaded the entire jaw. Beside each of the creature's rep- 
 tile teeth, in both jaws, there was a deep pit, which 
 received the reptile tooth opposite ; and thus, when the 
 animal closed its formidable mouth, the jaws would have 
 been locked together by their long teeth and deep recip- 
 ient hollows, as the crenellated jaws of a fox-trap lock into 
 each other when we release the spring. The other ich- 
 thyolite of the Old Red Sandstone to which I shall refer 
 is the Coccosteus, — a ganoid that, so far as we yet know, 
 was restricted to this formation. Like the Ptei'ichthys, 
 with which it has been classed, it was provided with a 
 helmet and cuirass of bony 2>late ; but its caudal portion 
 seems to have been naked, — a peculiarity of which we 
 find no other example among the ganoids of this early 
 time. The Coccosteus was, howevei', chiefly remarkable 
 for the form of its jaws.^ More than ten years ago I ven- 
 tured to state, in the first edition of a little work on the 
 Old Red Sandstone, that the jaws of this ancient fish 
 seemed, like those of some of the crustaceans, and of some 
 of the insects, to have possessed a horizontal action. 
 Aware, however, that I was on dangerous ground, I exer- 
 cised, in making the statement, some little share of Scotch 
 caution: the thing was, I stated, too anomalous to be 
 regarded as proven by the evidence of the specimens yet 
 found ; and I mentioned it, I said, with but the view of 
 directing attention to it. It was a question, I thought, 
 worthy of being entertained, and so I craved that it shauld 
 be entertained, and specimens carefully examined. But 
 
 1 Tlic Coccosteus possessed also true bony vertebratse. See " Siluria," 
 p. 504, new edition. — W. S. S.
 
 LECTURES ON GEOLOGY. 265 
 
 specimens were not examined, at least no specimens that 
 threw any light on the subject; and my very modified 
 statement respecting it was written down a blunder on 
 the very higliest authority, I kept, however, a steady 
 eye on the rocks, as the real authorities in the case ; and, 
 deeming myself bound as a geologist to observe carefully 
 and record truthfully whatever they revealed, but as not 
 in the least responsible for the anomalies of the revela- 
 tion, I persisted in quietly collecting their evidence in a 
 suite of fossils, which has now fully convinced our first 
 comparative anatomists that there was an anomaly in the 
 structure of the jaws of this ancient fish, unique among 
 the vertebrata; and that, in calling to it the attention of 
 the scientific world, I was in the right, not in the wrong. 
 The under jaws contained two distinct sets of teeth ; the 
 one set or group in the line of the symphysis, the other 
 set or group on the upj^er edge of the jaw, and placed on 
 such diflferent planes, that they could not possibly have 
 been brought into action by the same movement of the 
 condyles. And there are on the table specimens which 
 show, that while the group in the customary place, the 
 upper edge of the under jaw, were made to act against 
 a group placed in the nether edge of the upper one by the 
 usual vertical action, the groups so strangely placed in 
 the symphysis, if brought into action at all, must have 
 acted against each other through a lateral motion alto- 
 gether unique. The jaws of the Coccosteus are interest- 
 ing in another point of view, as being perhaps the oldest 
 portions of any internal skeleton that have presented their 
 structure to the microscope. And it is surely not unin- 
 teresting to see the osseous substance, destined to i:)erform 
 so important a part in the animal economy, presenting in so 
 early an age its distinguishing characteristics ; in especial 
 
 23
 
 266 LECTURES ON GEOLOGY. 
 
 those arterial haversion canals through which the ancient 
 blood must have flown for its nourishment, and those 
 numerous corpuscles of life-points from which its organi- 
 zation began, and which continued to remain open as the 
 sheltering cells in which its vitality resided. Was it im- 
 possible, in the nature of things, we ask, that life could be 
 equally diffused over hard and rigid earth built up into 
 this new animal substance, bone? and was it therefore 
 merely sown over it in hollow microscopic points? Is 
 bone rather a thing strongly garrisoned by vitality, than 
 itself vital? Direct questions cannot always, in the present 
 imperfect state of our knowledge, receive answers equally 
 direct ; and these are questions to wliich our first physiol- 
 ogists might hesitate to reply. But we may at least safely 
 infer, from the thorough identity of the osseous material 
 throughout all ages, that it was a material compounded at 
 all times by the same Architect, according to a prede- 
 termined recipe ; that it is He who built up the corpuscles 
 and arranged the canals in that ancient jaw which so 
 excites our curiosity, that now maketh in the human 
 subject "the bones to grow;" and that, in his eternal 
 purposes, the existences of the most ancient times may be 
 woven into the tissue of one great plan, with all that now 
 exists, and with all that shall exist in the future. ■ 
 
 In retiring into the remote past, and descending from 
 formation to formation as we retire, we have now reached 
 i that great Silurian group of rocks in Avhich, so far as the 
 geologist yet knows, fossils first ajjpear, and which repre- 
 sents a period of incalculable vastncss, in which life, ani- 
 mal and vegetable, seems to have had its earliest begin- 
 nings on our planet. Enormous as is the depth of some 
 of the other systems, — such as the Old Red and the Car- 
 boniferous systems, — they shrink into moderate dimen-
 
 LECTURES ON GEOLOGY. 267 
 
 sions when we compare them with the truly vast Sihirian 
 deposit. It was estimated only a few years ago, that the 
 entire depth of all the fossiliferous strata did not much 
 exceed six miles : it is now found by the geologists of the 
 Government survey, that the Lower Silurian strata of 
 North Wales are of themselves about five miles in depth, 
 while the Upper Silurian, as estimated by Sir Roderick 
 Murchison, are about a mile more. Many of the beds, 
 too, of both the Upper and Lower divisions must have 
 been of exceedingly slow deposition, — formed far from 
 land, and at the bottom of deep seas : nay, there are Silu- 
 rian Limestones that can scarce be regarded as deposits 
 at all, seeing that every calcareous particle of which they 
 are composed was at one time associated with animal life, 
 as the joints of crinoidea, the calcareous framework of 
 corals, or the shells of molluscs, all of which 'lived and 
 died upon the spot that the rocks now occup)^ And 
 rocks of this character, when of any considerable thick- 
 ness, must have been very many years in the forming. 
 The sagacious Chalmers saw and taught, at the beginning "7 
 of the present century, that "the writings of Moses do ' 
 not fix the antiquity of the globe : " "if they fix anything' 
 at all," he said, " it is only the antiquity of the species." 
 But there were few among either teachers or pupils who 
 saw so clearly as Chalmers ; and when the geologist first 
 began to demand a long tale of years for the production 
 of all the stony volumes of his record, it was, like the 
 long price wKich the ancient sibyl demanded for all her 
 volumes, very decidedly refused him. Instead, however, 
 of bating in the demand, or acquiescing in the denial, the 
 geologists have been ever and anon returning, sibyl-like, 
 to drive harder and yet harder bargains, and even to ask, 
 as they do now, as much for a single volume as thev form-
 
 268 LECTURES ON GEOLOGY. 
 
 erly asked for the whole; but their library, unlike that 
 offered in sale to the old Roman, is undergoing no diminu- 
 tion in bulk ; on the contrary, its volumes increase in 
 number as the demand made for each is raised. But it 
 is at least something to be made to feel, by means of these 
 time-marks in the remote distance, that eternity is not a 
 mere idle name, which at times children employ in their 
 catechisms, but a great and awful fact; and that its un- 
 measurable amplitude of duration closes as completely 
 around the systems of the geologist in time, as the infinity 
 of extension closes around the systems of the astronomer 
 in space. It is one of the revealed characteristics of the 
 Adorable Creator, that " from everlasting to everlasting 
 he is God." 
 
 On the western coasts of Koss and Sutherland, on a 
 general basement of broken primary hills of no great alti- 
 tude, we find the ( Cambrian) deposit occurring as a series 
 of noble mountains, now entirely insulated from each other, 
 and that yet give evidence, in their lines of nearly horizon- 
 tal strata, that they once formed parts of a continuous bed, 
 which, ere the operation of the denuding agencies, had 
 overlaid, to the depth of from two to three thousand feet, 
 the gneiss and quartz deposits below. They now exist, 
 however, as a group of magnificent pyramids, compared 
 with which those of Egypt are but the toy erections of 
 children ; and yet, from the rectilinear character of their 
 abrupt and mui-al precipices, coursed as if with tears of 
 ashlar, — from their general regularity of form, their utter 
 bareness of vegetation, and their rich, warm color, which 
 contrasts as strongly with the cold gray tints of the rocky 
 platform on which they rest, as the warm color of our 
 fresher public buildings with the cold gray of our paved 
 streets or squares, — they seem rather works of human
 
 LECTURES ON GEOLOGY. 269 
 
 contrivance than productions of Nature. Seen from the 
 west in a clear summer evening, when. the red level light 
 falls on the still redder stone, but at a sufficient distance 
 to admit of those softening influences of the atmosphere 
 which mellow the harsher reds into crimson and purple, 
 there is a gorgeous beauty in these pieces of Nature's 
 masonry which it is scarce possible to exaggerate in de- 
 scrij^tion. Beneath and in front we see a tumbling sea of 
 craggy hills, which even the warm gleam of sunset scarce 
 relieves from their sober tint of neutral gray; while rising 
 over them abrupt and bold, and lined with their horizontal 
 bars, appear the noble pyramids in their rich vestures of 
 regal purple, — the monuments of an antiquity compared 
 with which that of Nineveh and Babylon belong to the 
 morning hours of a day not yet come to its close.^ 
 
 But it is peculiarly in the southern Silurian portions of 
 the kingdom that "scarce a mountain lifts its head un- 
 sung." Yarrow, Ettrick, St. Mary's Loch, Leader Haughs, 
 Tweedside, — especially along those upper reaches of the 
 river where it mirrors, in its calmer pools, the classic ruins 
 of Melrose and Dryburg, and the young woods of Abbots- 
 ford, — the Galawater, Teviotdale, Lamraermuir, Galloway,, 
 and Nithsdale, the springs of the Doon, the hills that 
 rise over the source of Dee, and the "moors and mosses 
 many" where tlie "Stinchar flows," — are all to be sought 
 and found in the Silurian region of Scotland. It will 
 scarce do now to estimate the scenic merit associated with 
 these names at its actual value. The words of sober truth 
 
 1 The above description of the scenery of the West Highlands is, in 
 fact, that of the Silurian, althoufrh written before Sir Roderick Murchison 
 discovered his error in laj'ing down these mountains as Old Red. It is 
 inserted here to fill up the hiatus in description which would else occur. 
 — L. M. 
 
 23*
 
 270 LECTURES ON GEOLOGY. 
 
 would seem, according to Wordsworth, " strange words of 
 slight and scorn," — 
 
 " What 's Yarrow but a river bare. 
 That glides the dark hills under? 
 There are a thousand such elsewhere, 
 As worthy of our wonder." 
 
 EA-en the indomitable good nature of Sir Walter was 
 scarce proof against what he deemed the disparaging, but, 
 I doubt not, truthful, estimate of Washington Irving. 
 "Our ramble," says this accomplished writer, in his "Ab- 
 botsford," "took us on the hills, commanding an extensive 
 prospect. 'Now,' said Scott, 'I have brought you, like the 
 pilgrim in the "Pilgrim's Progress," to the top of the 
 Delectable Mountains, that I may show you all the goodly 
 regions hereabouts. Yonder is Lammermuir and Smal- 
 holrae ; and there you have Galashiels, and Torwoodlee, 
 and Galawater; and in that direction you see Teviotdale 
 and the braes of Yarrow, and Ettrick stream winding 
 along, like a silver thread, to throw itself into the Tweed.' 
 He went on thus to call over names celebrated in Scottish 
 song, and most of which had recently received a romantic 
 interest from his own pen. In fact, I saw a great part of 
 the border country spread out before me, and could trace 
 the scenes of those poems and romances which had in a 
 manner bewitched the world. I gazed about me for a time 
 with mute surprise, I may almost say with disappointment. 
 I beheld a mere succession of gray, waving hills, line be- 
 yond line, as far as my eye could reach, monotonous in 
 their aspect, and sp destitute of trees, that one could almost 
 see a stout fly walking along their profile ; and the far- 
 famed Tweed appeared a naked stream, flowing between 
 bare hills, without a tree or thicket on its banks. I could 
 not help giving utterance to my thoughts. Scott hummed
 
 LECTURES ON GEOLOGY. 271 
 
 for a moment to himself, and looked grave. He had no 
 idea of having his muse complimented at the expense of 
 his native hills. ' It may be partiality,' said he, at length ; 
 * but to my eye these gray hills, and all this wild border 
 country, have beauties peculiar to themselves. I like the 
 very nakedness of the land : it has something bold, and 
 stern, and solitary about it.' " Yes ; there is no question 
 that, had not the poets thought so, they could not have 
 sung so honestly and warmly, and, of consequence, so 
 successfully : 
 
 " The poet's lyre, to fix his theme, 
 Must be the poet's heart;" 
 
 and so let us with a good grace acquiesce in their decision. 
 The border land, with its Silurian groundwork, has its 
 peculiar beauties ; and no one could portray them at once 
 so graphically and so discriminatingly as Scott himself 
 Take, for instance, the passage in "Guy Mannering," where 
 he describes his hero, Brown, and the redoubtable Dandy 
 Dinmont, approaching Charlieshope after the rencontre 
 with the gipsies on Bewcastle Moor. " Night was now 
 falling, when they came in sight of a pretty river, winding 
 its way through a pastoral country. The hills were greener 
 and more abrupt than those which Brown had lately passed, 
 sinking their grassy sides at once upon the stream. They 
 had no pretensions to magnificence of height, or to roman- 
 tic shapes, nor did their smooth swelling slopes exhibit 
 either rocks or woods; yet the view was wild, solitary, 
 and pleasingly rural. No inclosures, no roads, almost no 
 tillage : it seemed a land where a patriarch would have 
 chosen to feed his flocks and herds." This is faithful de- 
 scription, at once beautiful and characteristic ; and such of 
 my audience as remember the exquisite landscape of the
 
 272 LECTURES OX GEOLOGY. 
 
 " Enterkin " of our countryman Harvey, as exhibited at the 
 Koyal Institution here, in — if I remember aright — the 
 year 1846, with its gray rocks, its green swelling hills of 
 softish outline, and its recluse and houseless valley of deej)- 
 est loneliness, will be convinced, as I am, that where there 
 is in the mind a certain prominent requisite present, the 
 region of the Silurians is as available for the purposes of 
 the painter as for those of the poet, — that one requisite 
 being the not very definable and many-sided faculty repre- 
 sented by the single magic word genius. 
 
 The Silurians of Scotland, though of veiy considerable 
 depth, are greatly less rich in organic remains than the 
 contemporary deposits of England and the Continent. 
 Vast beds of gray slaty rock, hundreds of feet in thickness, 
 seem to have been formed at the bottom of profound seas 
 beyond the zero line of animal or vegetable life. And even 
 in the cases in which organisms of both kingdoms were 
 present, we find their remains very imperfectly preserved.-' 
 The flora of the system in Scotland is represented merely 
 by a few dark-colored carbonaceous beds, which occasion- 
 ally pass into an impure anthracite or blind coal, and which 
 are probably identical in their origin with the anthracite 
 schists of Scandinavia, regarded by Sir Roderick Murchi- 
 son as the remains of large forests of algae and fuci, which 
 originally existed in the Silurian seas, and which, from 
 their perishable nature, have lost all trace of their original 
 forms. In the ashes of an anthracite of our Scottish Silu- 
 
 1 As mentioned in the preface, it is stated bj- Sir Rodericic Murchison, in 
 his Leeds address to the British Association, that twenty species of Silu. 
 rian fossils have been discovered by Mr. Peacli in a limestone band above 
 the Silurian confrlomcratc of the Western Hijrhlands, determined by Mr. 
 Salter, and carefully examined by Sir Roderick himself. They are Maclu- 
 rea, Murchisonia, Cephileta, and Orthoceras, with an Orthis, etc. — L. M.
 
 LECTURES OX GEOLOGY. 273 
 
 rians, which occurs near Traquair, Professor Nicol, of 
 Cork, observed, under the microscope, tubular fibres un- 
 questionably vegetable, but which he thought indicative of 
 vegetation of a higher class than our existing algae. There 
 is, however, a flimily of marine plants now represented on 
 our coasts by a single species, which had, I am inclined to 
 think, its representatives at a very early period in our seas ; 
 and which, had it existed during the Silurian ages, could 
 have furnished the tubular cells. I refer to the Zostera, or 
 grass- wrack, a plant of the pond-weed family, which, unlike 
 any of the algae, has true roots, true flowers, true seeds, 
 tough fibrous stems, and grass-like leaves, traversed by 
 parallel veins, and that yet lives in the sea among lamina- 
 rice and floridice, far below the fall of our lowest stream- 
 tides. It is worthy of notice, too, that the Zostera marina, 
 our recent British species, when driven ashore on parts of 
 our coasts at certain seasons. — as it always is, in great 
 abundance, — decomposes into a substance much resem- 
 bling peat, that, unlike the brown pulpy mass into which 
 the algae in similar circumstances resolve, retains distinct 
 trace of the vegetable fibre. It is further noticeable, that 
 some of the vegetable remains of the Old Red Sandstone 
 — the oldest specimens furnished by our Scottish flora that 
 present aught approaching distinctness of outline — exhibit 
 several traits that remind us of the leaves of gigantic 
 Zostera. The vegetable impressions of some of the Caith- 
 ness flagstones have rectilinear edges, and are traversed by 
 parallel lines, scarce less strongly marked than the ridges 
 of the Calamite ; but, from the extreme thinness of the 
 impression left in the rock, they seem rather the veins of 
 leaves than the fluted markings of stems. It is quite pos- 
 sible, therefore, that though the anthracite beds of our 
 Scottish Silurian system give evidence of the existence of
 
 274 LECTURES ON GEOLOGY. 
 
 a higher vegetation than that of the algpe, it may have 
 been a marine vegetation notwithstanding. No terrestrial 
 plant has yet been detected in the Silurians of either Eng- 
 land or Scotland : the flora of the time, within at least the 
 area of the British islands, seems to have been a poverty- 
 stricken flora of the sea, consisting mainly of Fuel and 
 Algae, and including as its highest forms a species or two 
 of Zostera, or, as is more probable, of some extinct analo- 
 gous fomily. 
 
 The Silurian fauna in Scotland consisted also, so far 
 as we can now judge from the broken remains, of but a 
 few marine forms. In the Silurian deposits of England 
 fishes appear; but in our Scotch Silurians we find nothing 
 higher than a Trilobite or a cephalopodous mollusc. 
 The Trilobite was perhaps the most characteristic organic 
 form of the system. It occurred, also, though in types 
 specifically distinct, in the Old Red Sandstones of England 
 and the Continent; and I have found well-marked spec- 
 imens even in the Mountain Limestone of this neigh- 
 borhood, — the formation in which the family finally dis- 
 appears ; but it was in the Silurian system that it received 
 its fullest development, both in size and number; and 
 portions of at least five species have been detected in 
 the Silurian deposits of Scotland. The Trilobite was a 
 many-jointed crustacean, which since the close of the Car- 
 boniferous pei'iod, has had no adequate representative in 
 creation, but whose nearest allies we have now to seek 
 among the minute Entomostraca, especially among the 
 genus Branchipus, — little insect-like creatures, occasion- 
 ally found in stagnant pools, furnished with fin-like legs, 
 fitted for swimming, but not for walking with, and that, 
 spending happy lives, darting hither and thither through 
 the upper reaches of the water, now swim along the sur-
 
 LECTURES ON GEOLOGY. 275 
 
 face on their backs, and now on their abdomens. The 
 Trilobites, like the Entomostraca, seem to have been 
 furnished with merely membranaceous, oar-like limbs, and 
 must have led a purely aquatic life as swimmers, — at one 
 time oaring their way, back below, along the surface of 
 the sea, at another, back above, along the bottom. But 
 some of these Entomostraca of the Old Silurian ocean 
 were, compared with their modern representatives, of 
 great size. The Homalonotus delphinocephalus had a car- 
 apace as large as that of an ordinary market crab, and the 
 Asaplms tyrannus and Isotehis megistos were each of 
 them as large animals, though different in their propor- 
 tions, as ordinary market-lobsters. But it seems to have 
 been characteristic of both the flora and fauna of these an- 
 cient times, that many of their characteristic forms should 
 unite great size to a humility of organization restricted 
 in the present ages to forms comparatively minute. The 
 Trilobites of the Silurian system, like the Club-mosses and 
 Equisetaceae of The Coal Measures, were of a Bi-ogdig- 
 nagian cast ; and, regarded as Entomostraca, we must hold 
 
 — to return to a former illustration — that we look upon 
 them with eyes sharpened by an experience acquired 
 among the productions of Lilliput. So fir as we yet 
 know, the higher contemporaries of the Trilobite in Scot- 
 land were chambered shells of two well-marked genera, 
 
 — that of the Orthoceratite, a long, straight, horn-shaped 
 shell ; and that of the Lituite, which may be described 
 as an Orthoceratite curled up into a scroll. And, asso- 
 ciated with these, we find some of the low brachio- 
 podous molluscs of the more ancient types, such as Lep- 
 teme, Orthes, and Spirifers. But by far the most char- 
 acteristic organisms of our Scottish Silurians belonged 
 to a low zoophitic family, allied by some of their afiin-
 
 276 LECTURES ON GEOLOGY. 
 
 ities, in some of their genera, to the sea-pens, and by cer- 
 tain other affinities, in some of their other genera, to the 
 Sertularia. They are known to the geologist by the gene- 
 ral name of Graptolites. The Sertularia, compound, plant- 
 like animals, that resemble miniature bushes in spring, 
 just as the buds are bursting into leaf, are attached al- 
 ways, by their seeming roots, to rocks, shells, or sea- 
 weed, and so require a hard bottom; whereas the sea- 
 pens, compound, feather-like Zoophites, Avhose every fibre 
 contains its rows of living creatures, affect soft muddy 
 bottoms, in which they may be found sticking by their 
 quill-like points, like arrows in the soft sward around a 
 target. I have seen them brought up by scores on the 
 lines of the fisherman, out of a muddy ravine in the Mo- 
 ray Frith, that sinks abruptly from beside the edge of a 
 hard submarine bank, to the depth of thirty fathoms ; and 
 have often admired their graceful, quill-like forms, and 
 their delicate hues, that range from pink to crimson, and 
 from crimson to purple. And, judging from the character 
 of those gray carbonaceous deposits in which the Grap- 
 tolites of our Silurian rocks most abound, it is probable 
 that they also were mud-loving animals, and more resem- 
 bled in their habitats, if not in their structure, the sea- 
 pens than the Sertularia. It is a curious circumstance 
 that, in the group at least, the Graptolites of Scotland are 
 more obviously allied to the Graptolites of the vast Silu- 
 rian deposits of Canada and the United States, than to 
 those of the Silurians of England. With this curious 
 zoophite we take farewell, in Scotland, of life and organ- 
 ization, and the i*ecord of the palasontologist closes. The 
 remains of no plant or of no animal have been detected in 
 this country underlying the rocks in which the oldest 
 Graptolites occur.
 
 LECTURES ON GEOLOGY. 277 
 
 Beneath the Silurian deposits of Scotland there rest, 
 to an enormous thickness, what, witli the elder geologists, 
 I shall persist in terming the primary deposits^ consisting, 
 in the descending order, of clay-slates, mica-schists, quartz- 
 rocks, primary limestones, and the two varieties of gneiss, 
 — the granitic and the schistose.^ In retaining the old 
 name, I must, however, be regarded as merely holding that 
 these rocks were actually the first-formed rocks of what 
 is now Scotland, — that the gneiss teas gyieiss, and the 
 slate was slate, ere ever our oldest fossilifero'us formations 
 began to be deposited, or the organisms which they contain 
 had lived or died. Into the question raised regarding the 
 form in which they were deposited, or the condition of 
 our planet during the period of their deposition, I do not 
 at present enter. On tlie other point, however, — the com- 
 parative antiquity of these unfossiliferous rocks in Scot- 
 land, — the evidence seems very conclusive ; the base of 
 some of the oldest deposits in which we find organisms 
 inclosed consists of broken, and in most cases water- 
 rolled, fragments of the gneisses, quartz-rocks, clay-slates, 
 and mica-schists of the primary regions of the country.^ 
 These primary regions are of great extent. The gneiss 
 region contains nearly ten thousand square miles of sur- 
 face ; the mica-schist, fully three thousand ; and the quartz- 
 rock and clay-slate united, about fourteen hundred miles 
 more. Comprising almost all the Highlands of Scotland, 
 with the greater part of two of our Lowland counties, 
 Banffshire and Aberdeen, their entire area, if we add about 
 fifteen hundred miles additional of granite and primary 
 
 1 HTi<rh Miller evidently more than suspected the history of the 
 geology of the north and northwest of Scotland, as developed by Mr. 
 Peach and Sir Roderick Murchison in 18-38. — W. S. S. 
 
 3 See Murchison's " Siluria," 2d edition, App. 553, 554, and 556. 
 
 24
 
 278 LECTURES ON GEOLOGY. 
 
 porphyry, does not fall sliort of sixteen thousand square 
 miles. It would be a bold and perilous task for one who 
 has in some degree apjireciated those sublimely impres- 
 sive word-paintings of the Highlands which have added so 
 largely to the well-earned celebrity of your distinguished 
 President, and which seem invested with the very atmos- 
 phere of our hills, or who has seen with admiration and 
 delight not only the very features, but all the poetry, 
 of our noble mountain scenery, glowing from the canvas 
 of Macculloch and of Hill, — it would, I say, be a perilous 
 t-isk under the recollection of achievements such as theirs, 
 to attempt a dull analysis of the geologic principles on 
 which the peculiarities of our Highland landscape depend. 
 I would feel as if I were bringing you from the studio 
 of some heaven-taught sculptor, crowded with shapes of 
 manly beauty and femiuine loveliness, to lecture, amid the 
 melancholy rubbish of a dissecting room, on the articula- 
 tions and proportions of the bones, and the form and 
 position of the muscles. I shall venture, therefore, on 
 merely a few desultory remarks, and shall request you, in 
 order to lighten them as much as possible, to accompany 
 me, first, in a sort of mesmeric expedition to the western 
 extremity of Glencoe ; at which, after having journeyed 
 us only the clairvoyant can journey, let us now deem our- 
 selves all safely arrived, and just set out on our way back 
 again by the Loch Lomond road. In the course of our 
 journey we shall pass, in the ascending order, over all the 
 great Primary formations.^ 
 
 1 According to a (lia<;ram which I have had the honor of receiving from 
 the luind of Sir Roderick Murchison, ilhistrating his latest explorations in 
 the north, there are two distinct gneisses, — an older and a younger; the 
 first underlying the Cambrian conglomerate and Silurian fossil-bearing 
 band of the west; the other or younger giiciss forming part of the central
 
 LECTURES ON GEOLOGY. 279 
 
 Let US first mark the character of the Glen, — not less 
 famous for the severe and terrible sublimity of its natural 
 features, than for that dark incident in its histor}^ which 
 associates in such melancholy harmony Avith the terrible 
 and the severe. We are in a region of primary porphyry, 
 — in the main a dark-colored rock, though it is one of its 
 peculiar traits, that in the coarse of a few yards it some- 
 times changes its hue from dark green to black or a deep 
 neutral tint, and from these again to chocolate color, to 
 brick red, or to iron gray. But the prevailing hues are 
 dingy and sombre; and hence, independently of the brown 
 heath and ling, and those deep shadows which always 
 accompany steep rocks and narrow ravines, a sombre tone 
 in the coloring of the landscape. "When, however, for a 
 few days the atmosphere has been dry and the sky serene, 
 the dark rocks seem in many parts as if strewed over with 
 an exceedingly slight covering of new-follen snow, — the 
 effect of the weathering of a thin film of the compact feld- 
 spar, which forms the basis of the porphyry into a white 
 l)orcelanic earth. It is, however, in the form of the rocks 
 that we detect the more striking peculiarities of the por- 
 phyritic formation. They betray their igneous origin in 
 their semi-columnar structure. Every precipice is scarred 
 vertically by the thick-set lines which define the thin irreg- 
 ular columns into which the whole is divided ; and as the 
 columnar arrangement is favorable to the production of 
 tall steep precipices, deep narrow corries, and jagged and 
 peaked summits, the precipices on either side are tall and 
 steep, the corries are deep and narrow, and the summits 
 
 nucleus, and underlying: the Old Red Sandstone conglomerates and ascend- 
 ing fossiliferous series of the east. Of course, the Cambrian will contain 
 fragments of the older, and the Old Red conglomerate fragments of the 
 younger gneiss. — L. M.
 
 280 LECTURES ON GEOLOGY. 
 
 cire sharp, spine-like and uneven. A hill of primary por- 
 phyry, where not too much pressed upon by its neighbor 
 hills, as trees pi-ess upon one another in a thick wood, so 
 that each checks the development of each, generally affects 
 a pyramidal form ; and we find fine specimens of the reg- 
 ulai-ly pyramidal hill in the upper part of the valley, just 
 as we enter on the open moor. I may mention, ere we 
 quit Glencoe, that the more savagely sublime scenery of 
 Scotland is almost all porphyritic. There is only one 
 other rock — hypersthene — which at all equals the pri- 
 mary porphyry in this respect ; and hypersthene is of com- 
 paratively rare occurrence in Scotland. It furnishes, how- 
 ever, one very noble scene in the Isle of Skye : the stern 
 and solitary valley of Corriskin, so powerfully described in 
 the " Lord of the Isles," is a hypersthene valley. 
 
 Emerging from Glencoe, we enter upon a scene that, 
 in simple outline, abstracted from the dingy tone of the 
 coloring, and the bleak and scanty vegetation common to 
 both, contrasts Avith it more strongly than j^erhaps any 
 other in Scotland. We have quitted the porphyritic re- 
 gion, and entered upon a region of granite and gneiss. 
 Looking back from that most solitary of Scottish inns, 
 King's House, we find that we can determine with much 
 exactness, from the form of the hills, where the porphyry 
 ends and the granite or gneiss begins. The last of the 
 porphyritic hills is a noble pyramid, broken into dizzy piec- 
 ipices, and lined vertically, like some of our semi-columnar 
 traps ; whereas the first of the granitic hills, placed imme- 
 diately beside it, with but a narroAV valley between, is of 
 rounded outline, — a mere hummock magnified into a 
 mountain, and wrapped round by a continuous cawl of 
 brown heath. On the other hand, we see the granite rol- 
 ling out into a moory jjlain, — one of the dreariest in Scot-
 
 LECTURES ON GEOLOGY. 281 
 
 land, — and forming a basin for a long, flat-shored loch, 
 whose brown waters do not reflect a single human dwel- 
 ling. Granite, however, does not always pi-esent features 
 so little attractive. It is, in truth, a many-charactered 
 rock. In general, the feldspar, which enters so largely into 
 its comj^osition, contains a considerable per centage of 
 potash, and so decomposes readily ; and hence the rounded 
 forms of many of our granite hills and boulders. It affects, 
 too, on the large scale, though unstratified, a tabular ar- 
 rangement, and sometimes exists, as in this instance, and 
 in those dreary parts of the lowlands of Aberdeen where 
 the patrimony of the redoubtable Sir Dugald Dalgetty lay, 
 as extensive and usually very barren plains. But in other 
 parts it has little or no potash in its composition ; and 
 forming, in these circumstances, one of the most durable 
 of rocks, its peaks and j^recipices stand up, as in Goatfell 
 in Arran, with all the porphyritic sharpness of outline, 
 unweathered for ages, or present, as in Ben Macdui and 
 its Titanic compeers, features at once bold, broad, and sub- 
 limely impressive. Humboldt, generally so correct in his 
 "Views of Nature," seems to have seized on the granite in 
 but one of its aspects. " All formations," we find him say- 
 ing, " are common to every quarter of the globe, and as- 
 sume the like forms. Everywhere basalt rises in twin 
 mountains and truncated cones ; everywhere trap porphyry 
 presents itself to the eye under the form of grotesquely- 
 shaped masses of rock ; while granite terminates in gently 
 rounded summits." 
 
 We pursue our journey, and enter on a great gneiss dis- 
 trict. And in its swelling hills, rolled, like pieces of plain 
 drapery, into but a few folds, and in its long withdrawing 
 valleys, more imposing from an element of simple extent 
 than fi-om aught peculiarly striking in their contour, we 
 
 24*
 
 282 LECTURES ON GEOLOGY. 
 
 recognize the staple scenery of the Scotch Highlands, — 
 the scenery of ten thousand square miles. A gneiss hill 
 is usually massive, rounded, broad of base, and withal some- 
 what squat, as if it were a mountain well begun, but in- 
 terdicted somehow in the building, rather than a finished 
 mountain. It seems almost always to lack the upper stories 
 and the pinnacles. It is, if I may so express myself, a hill 
 of one heave; whereas all our more imposing Scottish hills, 
 — such as Ben Nevis and Ben Lomond, — are hills of at 
 least two heaves; and hence, in journeying through a 
 gneiss district, there is a frequent feeling on the jjart of 
 the traveller that the scenery is incomplete, but that a few 
 hills, judiciously set down upon the tops of the other hills, 
 would give it the proper finish. No hill, however, accom- 
 plishes more w^ith a single heave than a gneiss one; the 
 broad-based Ben Wyvis, that raises its head, white with 
 other snows than those of age, more than three thousand 
 feet over the sea, and looks down on all the other moun- 
 tains of Ross-shire, is a characteristic gneiss hill of a single 
 heave. Quitting the gneiss region, we cross a compara- 
 tively narrow strip of quartz rock. The quartz hills in its 
 course are, however, not very characteristic. Such of you 
 as may have sailed over the upper reaches of Loch Maree, 
 with its precipitous, weather-bleached pyramidal hills, so 
 bare of vegetation atop that their peaks may be seen 
 gleaming white in the autumnal moonlight for miles, as if 
 covered with snow, or who may have threaded your way 
 through the deep and sterile valleys that open their long 
 vistas towards the head of the lake, will be better able to 
 conceive, than from aught witnessed in the course of our 
 present day's journey, of the savage wildness of scenery — 
 savage and wild, but grand withal — which is the jiroper 
 characteiistic of a quartz-rock district.
 
 LECTURES ON GEOLOGY. 283 
 
 And now, the strip of quartz rock passed over, we enter 
 into an extensive region of mica-schist, — a formation so 
 favorable to the development of a picturesque beauty, — 
 ever and anon rising into the sublime, — that what is pecu- 
 liarly the classic ground of Highland scenery is to be found 
 within its precincts. Loch Awe, Loch Long, Loch Goil, 
 Loch Tay, by much the larger and finer part of Loch Lo- 
 mond, all Loch Katrine, Ben Venue, Ben Ledi, Ben Lo- 
 mond, and the Trossachs, with many a fine lake and 
 stream besides, and many a noble hill, are included in this 
 rich province of the mica-schist. 
 
 We first become aware that Ave are nearing the forma- 
 tion by the peculiar contour of its hills, as seen at a dis- 
 tance of several miles. As we approach their gray rocks 
 of silky lustre, we find that they are curved, Avrinkled, 
 contorted, so as to remind us of pieces of ill-laid-by satin, 
 that bear on their crushed surfaces the creases and crump- 
 lings of a thousand careless foldings ; and mark fiirther, 
 that it is to these curves and contortions of the strata 
 that the tubercled outlines of the hills are owing, and, 
 with these, the bold pi-ojecting knobs and sudden recesses 
 which break up their surfaces into so many picturesque 
 wildernesses of light and shade. Not unfrequently, how- 
 ever, vast masses of schist, of a structure as dense and 
 solid as that of granite, occur in the micaceous districts ; 
 and these form hills of a simpler outline, which, like the 
 rock which composes them, seem intermediate in character 
 between the mica-schist and the gneiss hills. All the 
 mica-schists, however, decompose into soils, which, though 
 light and thin, are more favorable to the production of the 
 grasses and the common dicotyledonous shrubs and trees 
 of the Highlands, than any of the gneisses or granites, and 
 greatly more so than the porphyries or quartz-rocks ; and
 
 284 LECTURES ON GEOLOGY. 
 
 SO the micaceous regions are not only more picturesque in 
 outline than any of the others, bat also richer in foliage 
 and softer in color. A tangled profusion of vegetation 
 forms quite as marked a feature in the living and breath- 
 ing description of the " Lady of the Lake," as the mural 
 picturesqueness of the ci'ags and precipices which the 
 vegetation half conceals ; and this, be it remembered, is 
 not an ordinary characteristic of the Scottish Highlands, 
 though true to natui'e in the mica-schist region selected 
 by Scott as the scene of his story. After employing, in 
 describing the rocks near Loch Katrine, well nigh half the 
 vocabulary of the architect, — spires, pyramids and pinna- 
 cles, — towers, turrets, domes, and battlements, — cupolas, 
 minarets, pagodas, and mosques, — he goes oa to say, 
 
 '* " Nor were these earth-born castles bare. 
 
 Nor lacked they many a banner fair; 
 / For from their shivered brows displayed, 
 
 i Far o'er the unfathomable glade, 
 
 \ All twinkling with the dewdrop's sheen, 
 
 The brier-rose fell in streamers green, 
 
 And creeping shrubs of thousand dyes 
 
 Waved in the west wood's summer sighs. 
 
 Boon nature scattered free and wild 
 I Each plant or flower, the mountain's child, 
 
 f Here eglantine embalmed the air, 
 
 Hawthorn and hazle mingled there, 
 
 The primrose pale and violet flower 
 ; Found in each cliff a naiTOw bower; 
 
 Foxglove and nightshade, side by side. 
 
 Emblems of punishment and pride, 
 
 Grouped their dark hues with every stain 
 
 The weather-beaten crags retain. 
 
 With boughs that quaked with every breath; 
 
 Gray birch and aspen wept beneath; * 
 
 Aloft the ash and warrior oak 
 
 Cast anchor in the rifted rock; 
 
 And higher yet the pine-tree hung 
 
 His shattered trunk, and frequent flung.
 
 LECTURES ON GEOLOGY. 285 
 
 Where seemed the cliffs to meet on high. 
 His boughs athwart the narrow sky." 
 
 Here is there a description of the characteristic vegetation 
 of our richer mica-schist valleys, not more remarkable for 
 its poetic luxuriance than for its strict truth, — truth so 
 strict and literal, that I question whether even the hyper- 
 critic, who looked for but a typical catalogue, could enu- 
 merate more than two forms of vegetation, prevalent in 
 such districts, which it does not include. The ferns grow 
 at once singularly rank and delicate in the shade, amid 
 the bosky recesses of the mica-schist ; and every damper 
 recess of the rock we find thickly tapestried over by the 
 mosses and the liverworts. 
 
 Passing southwards along the dark surface of Loch 
 Lomond, skirted for rather more than two-thirds of its 
 length by these hills of mica-schist, which confer on its 
 upper reaches a character of mingled j^icturesqueness and 
 sublimity, we enter, nearly opposite the pastoral village of 
 Luss, on a band of clay-slate, — the last or most modem 
 of the primary formations. It is of no great breadth, — 
 some three or four miles at most ; but it runs diagonally 
 across the entire kingdom, from the western shores of 
 Bute, where it disappears under the outer waters of the 
 Frith of Clyde, to near Stonehaven, where we lose it in 
 the German Ocean. We find it associated with a softer 
 style of scenery than the mica-schist. Lacking the mul- 
 titudinous contortions, and consequent knobs and pro- 
 tuberances, of the schist, it is less picturesque, though 
 scarce less beautiful ; nor is its beauty devoid of an en- 
 nobling mixture of the sublime. The gracefully-contoured 
 hills that rise immediately behind Luss, with their recluse 
 withdrawing valley, — the green rolling meadow on which 
 the village is built, — and in front the bolder and finer
 
 286 LECTURES ON GEOLOGY, 
 
 islands of the lake, — belong all to the clay-slate, and com« 
 pose a very characteristic landscape. Dunkeld, Comrie, 
 and the fine country to the north and west of Callendar, 
 including Loch Vennacher, with many a scene besides, of 
 a character intermediate, as becomes their place, between 
 the Highlands and the Lowlands, occur in the belt of clay- 
 slate that sweeps in its diagonal course from sea to sea. 
 Leaving Luss behind us, we enter, ere quitting the lakes, 
 on what is unmistakably the low country. The frame- 
 work of the land befoi'e us and on either hand, with that 
 of about one-half the lower islands of Loch Lomond, is 
 all formed of the Old Red Sandstone ; and what Byron 
 would pei-haps term the "domestic beauties" of the pros- 
 pect, — swelling hills ploughed to the top, green lanes, 
 rich meadows, and woods whose rectilinear edges still tell 
 of the planter's line, — bear evidence to the fact. The 
 land, however, is that of Buchanan and of Smollett. Both 
 were born on the Old Red Sandstone here; and the latter, 
 in his well-known description of the lake, in "Humphrey 
 Clinkei-," — the product of a time when descriptions of 
 Scottish scenery were less common than they are now, — 
 places in the foreground, in a style unmistakable from 
 their truth, the features of this Lowland formation, which, 
 in his age, was unfurnished with a name. " I have seen," 
 he says, "the Lago di Garda, Albano, De Vico, Bolsina, 
 and Geneva, and, upon my honor, prefer Loch Lomond to 
 them all, — a preference which is certainly owing to the 
 verdant islands that seem to float upon its surface, afibrd- 
 ing the most enchanting objects of repose to the excursive 
 view. Nor are the banks destitute of beauties which 
 even partake of the sublime. On this side they display a 
 variety of w^oodland, corn-fields, and pasture, with several 
 agreeable villas emerging, as it were, out of the lake, till.
 
 LECTURES ON GEOLOGY. 287 
 
 at some distance, the prospect terminates in huge moun- 
 tains covered with heath. Everything here is romantic 
 beyond imagination : the country is justly termed the 
 Arcadia of Scothand." In the corn-fields here, the wood- 
 lands, and the pastures, we recognize the Loidand features 
 of the Old Red placed prominently in the foregroiind; 
 and in the huge mountains in the distance, the bolder 
 Highland features of the clay-slate and the mica-schist. 
 In still journeying southwards, we skirt the banks of the 
 Leven, — the stream which connects the waters of the 
 lake with those of the Clyde, and which, for the greater 
 part of its course, runs over an Old Red Sandstone of the 
 same age as that of Balruddery, Carmylie, and Turin, and 
 which presents as its characteristic organism, the Cepha- 
 laspis. And nowhere in Scotland, as is well shown in 
 Smollett's classical Ode, is there a more thoroughly Low- 
 land river. 
 
 " Pure stream, in whoi^e transparent wave 
 My youthful limbs I wont to lave ; 
 No torrents stain thy limpid source. 
 No rocks impede thy dimpling course. 
 That sweetly warbles o'er its bed, 
 With white, round, polished pebbles spread. 
 Devolving from thy parent lake, 
 A charming maze thj' waters make. 
 By bowers of birch and groves of pine, 
 And hedges flowered with eglantine." 
 
 Ere, )vowever, closing our journey of a day, which intro- 
 duces us to so interesting an epitome of the scenery of 
 the primary rocks and the Scottish Highlands, we are 
 startled in the midst of the low country by scenery which 
 seems to be that of the Highlands repeated, but on a 
 smaller scale, and, if I may so express myself, in a more 
 mannered style. "We pass over a narrow belt of the trap-
 
 288 LECTURES ON GEOLOGY. 
 
 rocks, which, like the stratified deposits of this part of the 
 kingdom, — clay-slate and Old Red Sandstone, — runs 
 from sea to sea, and which, including in its range the 
 Campsie and the Ochil hills, is here represented by the 
 picturesque double-peaked rock which bears the ancient 
 fortalice of Dumbarton, — the castle which, according to 
 Jeanie Deans's friend, Mr. Archibald, was always given in 
 keeping to the best man in Scotland, — at one time to 
 Sir William Wallace, at another to the Duke of Argyle. 
 
 The depth of the primary stratified rocks, which in 
 Scotland must be very great, has been variously estimated 
 by geologists, as low as five and as high as ten miles, — . 
 evidence enough, did we require any such, that there must 
 be some degree of obscurity in the data on which the 
 calculations regarding it have been founded. It is always 
 extremely difficult to estimate the thickness of even a 
 clay-slate or quartz-rock deposit in a mountainous coun- 
 try, where the centres of disturbance are numerous and 
 involved; and in gneiss and mica-schist — always greatly 
 contorted deposits — the difficulty is so enhanced, that 
 what begins as calculation usually ends as guess. But 
 we at least know that it can be no thin series of deposits, 
 however much their strata may be contorted, or however 
 often repeated, that covers, in highly inclined positions, 
 tracts of country so extended as even those which we find 
 covered by them in the Scotch Highlands. In crossing 
 the four primary stratified deposits — clay-slate, mica- 
 schist, quartz-rock, and gneiss, — at right angles with the 
 line in which they traverse the country in the southern 
 division of the Highlands, we find them occupying, as 
 from near Crieff to Fort-Augustus, a tract rather more 
 than sixty miles across; and in crossing at the same angle 
 the northern division of the Highlands, — as from Glen
 
 LECTURES ON GEOLOGY. 289 
 
 TJrquhart to the middle reaches of Loch Carron, — we 
 find a tract of nearly forty miles occupied by the gneiss 
 alone. The question is one on which I would not choose 
 to dogmatize ; but an estimate that gave to our Scottish 
 primary rocks an aggregate thickness of from six to eight 
 miles I would not regard as by any means too high. A 
 more vexed question, however, and a still more doubtful 
 one, respects their formation. In what form, and under 
 what circumstances, it has been often asked, and very 
 variously answered, were these stratified primary rocks 
 deposited ? 
 
 They exhibit with almost equal prominence two distinct 
 classes of phenomena, — an igneous class and an aqueous 
 class; and are as intimately associated with the Pleistocene 
 rocks by the one, as Avith the sedimentary rocks by the 
 other. I have seen in the same quarry of quartz-rock, 
 one set of strata as decidedly chemical in their texture as 
 porphjTy or hyjiersthene, and another intermingling set 
 as decidedly mechanical as grauwacke or conglomerate. 
 I have seen, too, in the same gneiss rock, the minute 
 plates of mica, so abundant in this formation, arranged 
 between the layers as decidedly on the sedimentary prin- 
 ciple as in a micaceous sandstone, and in the layers them- 
 selves as decidedly on the crystalline principle as in 
 granite. And this compound character of the gneiss may 
 be regarded as the general one, with, of course, certain 
 exceptions in all the primary stratified rocks : the condi- 
 tion of their stratification is mechanical and sedimentary, 
 but the condition of the strata themselves igneous and 
 chemical. How were these variously-blended chai\acters 
 first induced ? The geologists of one school tell us that 
 the primary formations originally existed as ordinary sedi- 
 mentary rocks, but that they have since been altered by 
 
 25
 
 290 LECTURES ON GEOLOGY. 
 
 the action of intense heat, and that, while the stratificar 
 tion remains as an evidence of their first condition, the 
 texture of the strata indicates the igneous change which 
 has passed over them ; while the geologists of another 
 school hold that their first deposition took place under 
 circumstances essentially unlike any which now exist, on at 
 least the surface of our planet, and that their mineralogical 
 conditions were, in consequence, originally different from 
 those of any deposition taking place at the present time, 
 or in any of the later geological ages. I am inclined to 
 hold that there is a wide segment of truth embodied in 
 the views of the metamorphists ; but there seems to be 
 also a segment of truth on the other side ; and so I must 
 likewise hold with their antagonists, that there existed 
 long periods in the history of the earth in which there 
 obtained conditions of things entirely different from any 
 which obtain now, — periods during which life, either 
 animal or vegetable, could not have existed on our planet; 
 and fuither, that the sedimentary rocks of this early age 
 may have derived, even in the forming, a constitution and 
 texture which, in present circumstances, sedimentary rocks 
 cannot receive. 
 
 The scientific world is subject, like the worlds of politics 
 and trade, to its periods of action and reaction. Those 
 who hold that the earth was once a molten mass through- 
 out, — nay, that at a certain, not very profound, depth its 
 matter may be still in an incandescent state, — may have 
 perhaps driven their theory too far; and the current at 
 present seems to have set in against them. Mr, Hopkins's 
 profound deductions on the phenomena of Precession and 
 Nutation have been held to establish that the crust of the 
 earth is at present a solid unyielding mass to the depth of 
 at least a thousand miles from the surface. "Nay, there
 
 LECTURES ON GEOLOGY. 291 
 
 is nothing in this inquiry," says Professor Nichol, in refer- 
 ring, in his late admirable work, " The Planetary System," 
 to the problem of Mr. Hopkins, — "there is nothing in 
 this inquiry rendering it impossible that the globe is solid 
 throughout; and assuredly, a distinct negative is given 
 to a whole class of prevalent geological conceptions, on 
 grounds vastly more solid than any which appear to sus- 
 tain them." And I find Sir Charles Lyell, in the latest 
 edition of his "Principles," — that of last year, — suggest- 
 ing the existence of a circle of superficial action on the 
 earth's crust, quite sufficient to account for an intermittent 
 igneous activity altogether independent of central heat, 
 and which might go on by fits and starts forever, and be 
 as powerful a million of years hence as in those incal- 
 culably ancient times when our Scottish gneiss was in the 
 forming. Accepting the theory of Sir Humphrey Davy, 
 of an unoxidized metallic nucleus of the globe, capable of 
 being oxidized all around its porphyry by the percolation 
 of water, and of evolving heat enough in the process to 
 melt the sun-ounding rocks, he thus provides jalutonic, 
 metamoi'phic, volcanic agencies ; and whereas Sir Hum- 
 phrey Davy held, that when a thick crust of oxide had 
 once formed in this way, it served to shut out the water, 
 and the chemical action became in consequence more and 
 more languid, till it altogether ceased. Sir Charles finds^ 
 in another but harmonizing theory, an expedient for rem* 
 vigorating the slumbering plutonic forces, and thus, after 
 a period of repose, renewing their activity. The oxygen 
 of the water is, of course, the oxidizing agent ; but watei 
 also contains hydrogen, and hydrogen is a deoxidizing 
 agent. " "When the oxidizing process was going on," 
 says Sir Charles, " much hydrogen would of necessity 
 be evolved : it would permeate the crust of the earth, and
 
 292 LECTURES ON GEOLOGY. 
 
 be stored up for ages in fissures and caverns ; and when- 
 ever it hapi^ened to come in contact with the metallic 
 oxides at a high temperature, tlie reduction of these oxides 
 would be the necessary result." And we have thus a 
 circle of forces, — oxidization of the metallic basis to 
 evolve the plutonic agencies, and deoxidization of the 
 oxides to produce the metallic basis again. The process 
 would somewhat resemble that on which the movement 
 of the steam-engine depends, and in which water is first 
 expanded into steam, and then the steam in turn con- 
 densed into water, and thus the action of the engine 
 kept up. 
 
 Now, I need not here say how thoroughly I respect the 
 judgment and admire the genius of Sir Charles Lyell, — 
 one of the greatest of geologists, and a man of whom Scot 
 land may well be proud ; nor need I say how much of 
 pleasure and instruction I owe to the rich and eloquent 
 writings of Professor Nichol. But, like Job's younger 
 friend, I too must take the liberty of showing forth my 
 opinion, and of giving expression to a conviction, on 
 grounds of which my audience must judge, that both Sir 
 Charles and the Professor have sufiered the reaction wave 
 to carry them too far. 
 
 Mr. Charles M'Laren, in a popular digest of Mr. Hop- 
 kins's deductions, which first appeared, if I remember 
 aright, in the "Scotsman" newspaper, and then in "JamC' 
 son's Philosophical Journal," referred, with his character- 
 istic caution, to the narrowness of the base on which they 
 rested. "Mr. Hopkins's conclusion, no doubt, rests," he 
 said, " on a narrow enough basis. It is somewhat like an 
 estimate of the distance of the stars deduced from a differ- 
 ence of one or two seconds in their apparent position, — • 
 a difference scarcely distinguishable from errors of obser-
 
 LECTURES ON GEOLOGY. 293 
 
 vation." Let us, however, waive the doubt imp/ied in this 
 remark, however important we may deem it, and grant, 
 for the argument's sake, that the base is sufficiently broad 
 for the superstructure erected upon it. Let us freely grant, 
 after first availing ourselves of Mr. M'Laren's protest, and 
 placing it on record, that that equatorial ring, thirteen 
 miles in thickness, which, by disturbing the balance of the 
 earth, is the cause of the phenomena of Precession and 
 Nutation, must be attached to a consolidated crust of at 
 least a thousand miles in thickness, in order to account for 
 the extreme slowness of the peculiar movement which it 
 induces. But let us then inquire how it happens that this 
 equatorial ring at all exists. If our earth was always the 
 stiff, rigid, unyielding mass that it is now, — a huge metal- 
 lic ball, bearing, like the rusty ball of a cannon, its crust of 
 oxide, — how comes it that its form so entirely belies its 
 history? Its form tells that it also, like the cannon ball, 
 was once in a viscid state, and that its diurnal motion on 
 its axis, when in this state of viscidity, e' ugated it, through 
 the operation of a well-known law, at the equator, and 
 flattened it at the poles, and made it altogether the oblate 
 spheroid which all experience demonstrates it to be. It 
 may be urged, however, that this form of our planet, which 
 seems to speak so unequivocally of law, may, after all, be 
 but accident. If so, it must be singular. What say the 
 other planets ? Of these, the form of three may be at least 
 approximately, and that of one exactly, ascertained. Ve- 
 nus, Mars, Saturn, are all, like our earth, oblate spheroids, 
 flattened at their poles, and elongated at their equators. 
 Their substance must have been spun out by their rotatory 
 motion in exactly the line in which, as in the earth, that 
 motion is greatest. But while we can only approximately 
 determine the values of the equatorial and polar diameters 
 
 25*
 
 294 LECTURES ON GEOLOGY. 
 
 of these three planets, in one great planet, Jupiter, we can 
 ascertain them scarce less exactly than in our own earth ; 
 — we can gauge, and measure, and fix the proportions 
 which his equatorial ring bears to his general mass. With 
 a diameter about eleven times larger than that of our 
 planet, and rotating on his axis in less than half the time, 
 the motion of the surface at his equator must be more than 
 twenty times greater than that of the earth's equatorial 
 surface, and his equatorial ring ought, even in proportion 
 to his huge bulk, to be more than twenty times as massive. 
 And what is the fact? While the thickness of the equato- 
 rial ring of the earth is only equal to about one three-hun- 
 dredth part of the earth's diameter, the equatorial ring of 
 Jupiter is equal to about the one fourteenth or fifteenth 
 part of his diameter. It is, as the integrity of the law 
 demands, more than twenty times greater in proportion to 
 his mass than the earth's equatorial ring, and absolutely 
 more than two thousand times greater. Here, then, is 
 demonstration th ' the oblate sphericity of the earth is a 
 conseqhence of the ea/th's diurnal moiion on its axis ; nor 
 is it possible that it could have received this form when in 
 a solid state. A glass ball made to revolve on a spindle, 
 when in a state of viscidity, elongates equatorially, and 
 flattens at its poles ; but, if allowed to cool in its original 
 form as a sphere, it retains its perfect sphericity without 
 change, let us whirl it as rapidly as we may : and no me- 
 chanic ever dreams of increasing the disk of a grindstone 
 simply by turning it round. The earth, then, when it 
 assumed its present form, could not have been a solidified 
 mass, like the glass sphere when cooled down, or like the 
 grindstone. 
 
 But is it not possible, it may be asked, that the diurnal 
 motion may so act on the depositions taking place in the
 
 LECTURES ON GEOLOGY. 295 
 
 i»ea, and forming sedimentary rock, or on a region of igne- 
 ous action interposed between the oxidized crust of the 
 earth and its solid metallic nucleus, and forming plutonic 
 or igneous rock — is it not possible that, in the course of 
 vastly-extended periods, the earth may have taken its form 
 under the influence of the motion exerted on sedimentary 
 deposition and plutonic intrusion and upheaval ? Nay, 
 what, we ask in reply, are the facts ? Does the diurnal 
 motion exercise any influence, even the slightest, on depo- 
 sition or plutonic intrusion ? The laws of deposition are 
 few, simple, and well known. The denuding and trans- 
 porting agencies are floods, tides, waves, icebergs. The 
 sea has its currents, the land its rivers ; but while some of 
 these flow from the poles towards the equator, others flow 
 from the equator towards the poles, uninfluenced by the 
 rotatory motion ; and the vast depth and extent of the 
 equatorial seas, show that the ratio of deposition is not 
 greater in them than in the seas of the temperate regions. 
 We have, indeed, in the arctic and antarctic currents, and 
 the icebergs which they bear, agents of denudation and 
 transport permanent in the present state of things, which 
 bring detrital matter from the higher towards the lower 
 latitudes; but they stop far short of the tropics ; they have 
 no connection with the rotatory motion ; and their influ- 
 ence on the form of the earth must be infinitely slight ; 
 nay, even were the case otherwise, instead of tending to 
 the formation of an equatorial ring, they would lead to the 
 production of two rings widely distinct from the equator. 
 And, judging from what appears, we must hold that the 
 laws of plutonic intrusion or upheaval, though more ob- 
 scure than those of deposition, operate quite as independ- 
 ently of the earth's rotatory motion. Were the case other- 
 wise, the mountain systems of the world, and all the great
 
 296 LECTURES ON GEOLOGY. 
 
 continents, would be clustered at the equator; and the 
 great lands and great oceans of our planet, instead of run- 
 ning, as they do, in so remarkable a manner, from south to 
 north, would range, like the belts of Jupiter, from east to 
 west. There is no escape for us from the inevitable con- 
 clusion that our globe received its form as an oblate sphe- 
 roid at a time when it existed throughout as a viscid mass. 
 Nor is it unworthy of remark, that the same arrangement 
 through which a fluid earth was moulded into this shape 
 under the impulsion of the rotatory motion, also secured 
 that when that earth came to be covered by a fluid sea, 
 placed under the same impulsive influence, it should cling 
 to it equably, like a well-fitted cloak, without falling off to 
 the poles on the one hand, or accumulating in a belt round 
 the equator at the other. 
 
 But time fails, and I cannot follow up this subject to its 
 legitimate conclusions. Allow me, therefore, simply to 
 state, that I must continue to hold, with Humboldt and 
 with Hutton, with Playfair and with Hall, that this solid 
 earth was at one time, from the centre to the circumfer- 
 ence, a mass of molten matter. Let us remember — I 
 employ here the words of Humboldt — that the great 
 chemist Sir Humphrey Davy, to whom we are indebted 
 for the knowledge of the most combustible metallic sub- 
 stances, renounced his bold chemical hypothesis in his last 
 work ("Consolations of Travel"), as "inadequate and un- 
 tenable;" and further, that, with the oblate sphericity of 
 the earth and the planets to be accounted for, those who 
 continue to hold what he rejected, will be reduced, if they 
 persist, to the unphilosophical necessity of regarding as a 
 consequence of miracle, a peculiarity of shajie easily ex- 
 plainable on the principles of known law. 
 
 Now, the fact of a molten earth involves a long series of
 
 LECTURES ON GEOLOGY. 297 
 
 conditions, each different from all the others, and from the 
 conditions of the present time. It involves the existence 
 of a period in the history of our planet when life, animal or 
 vegetable, was not, and of a succeeding period, when life 
 began to be. It involves, too, the ripening of the earth, 
 from ages in which its surface was a thin, earthquake-sha- 
 ken crust, subject to continual sinkings, and to fiery out- 
 bursts of the plutonic matter, to ages in which it "is the 
 very nature of its noblest inhabitant to calculate on its 
 stability as the surest and most certain of all things. It 
 involves, in short, those successive conditions of life in the 
 geologic ages, which, in connection with what is now Scot- 
 laud, I have, I am afraid, all too inadequately attempted to 
 set before you in my present course. In fine, the primary 
 rocks, when they underlie to a great thickness, as in our 
 own country, the Palaeozoic deposits, I regard as the de- 
 posits of a period in which the earth's crust had sufficiently 
 cooled down to permit the existence of a sea, with the 
 necessary denuding agencies, — waves and currents, — 
 and, in consequence, of deposition also ; but in which the 
 internal heat acted so near the surface, that whatever was 
 deposited came, as a matter of course, to be metamorphosed 
 into semi-plutonic forms, that retained only the stratifica- 
 tion. I dare not sj^eak of the scenery of the period. We 
 may imagine, however, a dark atmosphere of steam and 
 vapor, which for age after age conceals the face of the sun, 
 and through which the light of moon or star never pene- 
 trates ; oceans of thermal water, heated in a thousand cen- 
 tres to the boiling point ; low, half-molten islands, dim 
 through the fog, and scarce more fixed than the waves 
 themselves, that heave and tremble under the impulsions 
 of the igneous agencies ; roaring geysers, that ever and 
 anon throw up their intermittent jets of boiling fluid, va-
 
 298 LECTURES ON GEOLOGY. 
 
 por, and thick steam, from these tremulous lands ; and, in 
 the dim outskirts of the scene, the red gleam of fire, shot 
 forth from yawning cracks and deep chasms, and thatbeai'S 
 aloft fragments of molten rock and clouds of ashes. But 
 should we continue to linger amid a scene so featureless 
 and wild, or venture adown some yawning opening into 
 the abyss beneath, where all is fiery and yet dark, — a soli- 
 tary hell, without sufiering or sin, — we would do well to 
 commit ourselves to the guidance of a living poet of true 
 faculty, — Thomas Aird, — and see with his eyes, and 
 describe in his verse : 
 
 " The awful walls of shadows round might dusky mountains seem, 
 But never holy light hath touched an outline with its gleam; 
 'T is but the eye's bewildered sense that fain would rest on form, 
 And make night's thick blind presence to created shapes confonn. 
 No stone is moved on mountain here bj^ creeping creature crossed. 
 No lonely harper comes to harp upon this fiery coast; 
 Here all is solemn idleness; no music here, no jars. 
 Where silence guards the coast ere thrill her everlasting bars ; 
 No sun here shines on wanton isles; but o'er the burning sheet 
 A rim of restless halo shakes, which marks the internal heat; 
 As in the days of beauteous earth we see, with dazzled sight, 
 The red and setting sun o'erflow with rings of welling light." 
 
 NOTE. 
 
 "The only shells I ever detected in the brick-clay of Scotland occurred in a 
 deposit in the neighborhood of St. Andrew's, of apparently the eame age as the 
 beds at Portobello." — Lecture Second, page 106. 
 
 Note. — Some time after this statement was made, Mr. Miller devoted himself 
 to a farther investigation of the brick-clay beds in the neighborhood of Porto- 
 bello, and discovered several species of shells in situ, especially great abundance 
 of Scrobtcularia piperata which he has described in a paper on the brick-clays, to 
 be published hereafter. They form a very interesting portion of his Museum, 
 now in the University of Edinburgh. " But for him,'" said an accomplished 
 geologist, in talking with me on the subject, " we would have known nothing 
 Whatever of the brick-clays." — L. M. 
 
 '^h.iK,
 
 DESCEIPTIVE SKETCHES 
 
 A GEOLOGIST'S PORTFOLIO.
 
 DESCRIPTIVE SKETCHES 
 
 OEOLOGIST'S PORTFOLIO. 
 
 GAUOrO SCALES AND RAYS. 
 
 The scales of the ganoid order consist of three plates, 
 — an inner, an outer, and an intervening one. The outer 
 is composed mainly of enamel, and retains, when entire, 
 however long exposed, much of the original dinginess of 
 hue which it bore in the quarry. The inner is a plane of 
 porcelanic-looking bone. The intermediate plate is finely 
 composed of concentric lines, crossed from the centre to 
 the circumference by finely radiating ones ; and when, as 
 mostly happens, this middle plate is exposed, the appear- 
 ance of a mass of scales through the glass is of great 
 beauty. The rays of our soft-finned fish, (Malacopterygii), 
 such as the haddock, seem as if cut through at minute dis- 
 tances, and then reunited, though less firmly than where 
 the bone is entire, with the design, it would seem, of giv- 
 ing to the organs of motion which they compose, the nec- 
 essary flexibility, somewhat on the principle that a carpen- 
 ter cuts half through with his saw the piece of moulding 
 which he intends bending along some rounded corner, or 
 forcing into some concave. But in the ancient ganoid 
 
 26
 
 302 DESCRIPTIVE SKETCHES FROM 
 
 fish, in which the rays are bare enamelled bones, and nec- 
 essarily of great rigidity, the joints appear real, not ficti- 
 tious. We see them cut across into short lengths, a single 
 fin consisting of many hundred pieces; and the problem 
 lay in conceiving how such a fin was to be wrought,— 
 ■whether, for instance, each detached length was to have 
 its moving ligament; and if so, how a piece of machinery 
 so very complicated and multifarious was to be set and 
 kept in motion. Here, however, I found the problem very 
 simply resolved. The rays of the ganoid fish, like its 
 scales, consist of three plates, — two i:>lates of enamel, one 
 on each side, and an interior plate of bone. Now the 
 joints, — though so well marked, that in rays imbricated 
 on the sides, as in those of the Cheirolepis, the imbricated 
 markings turn the corners, if one may so speak, just as the 
 carvings on a moulding recounter, as a workman would 
 say, at the corners of a building, — are not real joints after 
 all : they reach but through the inflexible enamel, leaving 
 the central plate of bone undivided. Like the rays of the 
 Malacopterygii, they are formed on the principle of the 
 half-sawn moulding. I observed, too, that the inner plate 
 is in every instance considerably narrower than the plates 
 of enamel which rest upon it. In the lateral edges of 
 every ray which composes the inner portion of the fin 
 there must exist a groove, therefore ; and in this groove, 
 it is probable, the connecting membrane at one time lay 
 hid, performing, like an invisible hinge, its work unseen. 
 
 RECENT BONE-BED IN THE FORMING. 
 
 I ONCE found an interesting illustration of the bone- 
 bed, coupled with at least one of the causes to which it 
 owes its origin, in the upper part of the Moray Frith. I
 
 A geologist's portfolio 308 
 
 had been spending a night at the hemng-fishing, on one 
 of the most fiimous fishing-banks of tlie east coast of Scot- 
 land, — the bank of Guilliara. It is a long, flat ridge of 
 rock that rises to within ten or twelve fathoms of the sur- 
 face. On its southern edge there is a submarine valley 
 that sinks to at least twice that depth ; and in the course 
 of the night our boat drifted from off the rocky ridge, the 
 haunt of the herrings, to the deepest part of the valley, 
 where scarce a herring is ever found. Our nets had, how- 
 ever, brought fish with them from the fishing-ground, suf- 
 ficient in quantity to sink them to the bottom of the hol- 
 low ; and in raising them up, — a work of some little 
 exertion, — we found them bedaubed with patches of a 
 stinking, adhesive mud, that, where partially washed on 
 the surface, seemed literally bristling over with minute 
 fish-bones. The muddy bottom of the valley may be 
 regarded as a sort of submarine burial-ground, — an ex- 
 tensive bone-bed in the forming. " What," we asked an 
 intelligent old fisherman, "brings the fish here to die? 
 Have you observed bones here before ?" " I have observed 
 them often," he said: "we catch few heri'ings here; but 
 in winter and spring, when the cold draws the fish from 
 off the shallows into deep Avater, we catch a great many 
 haddock and cod in it, and bring up on our lines large 
 lumps of the foul bottom. In spring, when most of the 
 small fish are sickly and out of season, and too weak to lie 
 near the shore, where the water is rough and cold, they 
 take shelter in the deep here, in shoals ; and thousands of 
 them, as the bones testify, die in the mud, not because 
 they come to die in it, but just because their sickly season 
 is also their dying season." And such seemed to be the 
 true secret of the accumulation. The fish resorted to this 
 place of shelter, not in order that they might die, but that
 
 304 DESCRIPTIVE SKETCHES FROM 
 
 they might live ; just as people go to poor-houses and 
 hospitals with a similar intention, and yet die in them, at 
 times, notwithstanding. And hence, I doubt not, in most 
 instances those accumulations of fish-bones which men 
 accustomed to the use of the irawl-net find in detached 
 spots of bottom, when in other j^arts, not less fx-equented 
 by fish in the milder seasons, not a single bone is to be 
 found, and which have been described as dying places. 
 The dying places, — the deep burial-grounds of the sea's 
 finny inhabitants, — will be found, almost always, to prove 
 their places of shelter. And hence, it is probable, many 
 of the bone-beds of the geologist. 
 
 DIPTERUS MACROLEPIDOTUS ABUlSfDAirr IN THE BANNISKIRK 
 OLD RED OF CAITHNESS. 
 
 Let the reader imagine a fish delicately carved in ivory, 
 and then crusted with a smooth shining enamel, not less 
 hard than that which covers the human teeth, but thickly 
 dotted with minute puncturings, as if stippled all over 
 with the point of a fine needle; — let him imagine the 
 enamelled rays lying so thickly in the fins, that no con- 
 necting membrane appears, and that each individual ray 
 consists of numerous pseudo-joints, so rounded at their 
 terminations, that each joint seems a small oblong scale, 
 or each ray, rather, a string of oval beads; — in due har- 
 mony with the rounded joints, let him imagine the scales 
 of a circular form, and so regularly laid on, that the ruler 
 ranges along them in three different ways, — from head to 
 tail, parallel to the deeply-marked lateral line, and in slant 
 angles across the body ; — immediately under the gill- 
 covers, which consist, as in the sturgeon, of but a single 
 plate a-piece, let him imagine two strong pectoral fins of
 
 A geologist's portfolio. 305 
 
 an angular form, with an interior angle in each coverecl 
 with small scales, and the rays, as in the case of the tail, 
 foi-ming but a fringe around it ; — let him imagine the ven- 
 tral fins, which lie far adown the body, of an exactly simi- 
 lar pattern, — angular projections covered with scales in 
 the centre, and fi-inged on two of their edges with rays ; 
 — exactly opposite to these, let there occur an anterior 
 dorsal fin of comparatively small size, and then exactly 
 opposite to the anal fin a posterior dorsal of at least twice 
 the size of the other ; — let the anal fin be also large and 
 sweeping, extending for a considerable way under the tail, 
 which must like the tails of all the more ancient fish, be 
 formed mainly on the under side, the vertebral column 
 running on to its termination ; — and the fish so formed 
 will be a fair representation of the ancient Dipterus. Pre- 
 senting externally in its original state no fragment of 
 skin or membrane, and with even its most flexible organs 
 sheathed in enamelled bone, it must have very much re- 
 sembled a fish carved in ivory. What chiefly struck me 
 in the examination was the peculiar structure of the ven- 
 tral fins, — the hind paws of the creature, if I may so 
 speak. Their internal angle of scales imparts to them an 
 appearance of very considerable strength, — such an ap- 
 pearance as that presented by the hind fins of the Ichthy- 
 osaurus, which, as shown by a lately-discovered specimen, 
 were furnished on the outer edges with a fringe of cartila- 
 ginous rays ; and I deemed it interesting thus to mark the 
 true fish approximating in structure, ere the reptilia yet 
 existed, to the reptile type. The young frog, when in its 
 transition state, gets its legs fully developed, and yet for 
 some little time thereafter retains its tail. The Dipterus 
 seems to have been a fish formed on this sort of transition 
 
 plan. 
 
 26*
 
 306 DESCRIPTIVE SKETCHES FROM 
 
 FOSSIL-WOOD OF THE OOLITE AT HELMSDALE, SUTHERLAND. 
 
 What first sti'ikes the observer in the appearance of the 
 fossil-wood of this coast is the great distinctness with 
 which the annual layers are marked. The harder lines of 
 tissue, formed in the end of autumn, stand out as dis- 
 tinctly on the weathered surfaces as we see them in pieces 
 of dressed deal that have been exposed for a series of 
 years to the light and the air. The winters of the Oolitic 
 period in this northern locality must have been sufiiciently 
 severe to have given a thorough check to vegetation. We 
 are next struck by the great inequality of size in these 
 layers, as we find them shown in separate specimens. I 
 brought with me one specimen in which there is a single 
 layer nearly half an inch in breadth, and another in which, 
 in no greater space, there occur fourteen difierent layers. 
 The tree to which the one belonged must have been in- 
 creasing in bulk fourteen times more rapidly than that of 
 the other. Occasionally, too, we find very considerable 
 diversities of size in the layers of the same specimen. 
 One year added to its bulk nearly half an inch ; in another 
 it increased scarce an eighth part. Then, as now, there 
 must have been genial seasons, in which there luxuriated 
 a rich-leaved vegetation, and other seasons of a severer 
 cast, in which vegetation languished. My microscope, a 
 botanist's, was of no great power ; but by using its three 
 glasses together, and carefully grinding down small patches 
 of the weathered wood till it began to darken, I could as- 
 certain with certainty, from the structure of the cellular 
 tissue, what, indeed, seemed sufficiently apparent to the 
 naked eye from the general appearance of the specimens, 
 that they all belonged to the coniferae. When viewed 
 longitudinally, I could discern the elongated cells lying
 
 A geulogist's portfolio. 307 
 
 side by side, and the medullary rays stretching at right 
 angles across ; but my glass lacked power to show the 
 glandular dots. When viewed transversely the regularly 
 reticulated texture of the coniferae was very apparent. A 
 bluish-gray limestone adhered to some of the specimens, 
 and bore evidence in the same track. It abounded in 
 cones and fragments of cones, in what seemed minute 
 needle-shaped leaves, and in thin detached pieces of bark, 
 like those which fall off in scales from the rind of so 
 many of the coniferae. The limestone bore also its fre- 
 quent fragments of fern. There seemed nothing lacking 
 to restore the picture. There rose before me a solemn 
 forest of pines, deep, shaggy, and sombre; its opening 
 slopes and withdrawing vistas were cheered by the lighter 
 green of the bracken ; and far beyond, where the coast 
 terminated, and the feathery tree-tops were relieved against 
 the dark blue of the sea, a long line of surf tumbled inces- 
 santly over a continuous reef of coral. 
 
 I picked up one very fine specimen, which, though it 
 weighed nearly a hundred weight, I resolved on getting 
 transported to Edinburgh, and which now lies on the floor 
 before me. It is a transverse cut of a portion of a large 
 tree, including the pith, and measures twenty-three inches 
 across. In the sections of trees, figured by Mr. Witham 
 in his interesting and valuable work, the original struc- 
 ture seems much disorganized : a granular radiating spar 
 occupies the greater portion of the interior ; and the tissue 
 is found to exist in but detached portions. Hei-e, on the 
 contrary, the tissue exists unbroken from the pith to the 
 outer ring. We may see one annual circle succeeding 
 another in the average proportion of about ten per inch ; 
 and though we cannot reckon them continuously, for 
 there are darker shades in which they disappear, — shades
 
 308 DESCRIPTIVE SKETCHES FROM 
 
 which the polisher of the marble-cutter may yet succeed 
 in dissipating, — the number of the whole must rather 
 exceed than fall short of a hundred. However obscure 
 the geologist may be in his eras generally, here at least is 
 the record of one century. But how were its years filled? 
 I sat beside the root of a newly-felled fir some six or eight 
 seasons ago, and amused myself, when the severed vessels 
 were throwing up their turpentine in minute transparent 
 globules, in reckoning the years by the rings, from the 
 bark inward. Here, I said, is the year in which the Re- 
 form Bill passed ; and this the year in which Canning 
 died ; and this the year of the great commercial crisis ; and 
 this the year of Waterloo ; and this of the burning of 
 Moscow. The yearly rings of the Oolite have no such 
 indices of recollection attached to them : we see their 
 record in the marble, but know no more of contemporary 
 history than that, when forests showed their fringes of 
 lighter green on the hill-sides, and cell and fibre swelled 
 under the rind, the promptings of instinct were busy all 
 around and beneath, — that the pearly ammonite raised 
 its tiny sails to the breeze, as the belemnite, with its 
 many arms, shot past below, — that nameless birds mingled 
 with flying reptiles, — and that, while the fierce crocodile 
 watched in his pool for prey, the gigantic iguanodon 
 stretched his long length of eighty feet in the sand. But 
 who shall reveal the higher history of the time ? The 
 reign of war and of death had commenced long before ; 
 and who shall assert that moral evil had not long before 
 cast its blighting shadows over the universe, — that there 
 had not been that war in heaven in which the uncreated 
 angel had overthrown the dragon, — or that unhappy intel- 
 ligences did not wander, "seeking rest, but finding none," 
 in an earth of " waste places," whose future sovereign still 
 \ay hid in the deep purposes of Eternity?
 
 A geologist's portfolio. 809 
 
 ASTREA OF THE OOLITE, SUTHERLAND. 
 
 The same deposit in which I found the wood embed- 
 ded, contains large masses of coral, all apparently of one 
 species, — not a branching coral, but of the kind which 
 consists of large stone-like masses covered on the surface 
 with stellular impressions, framed in polygons, and which 
 composes the genus Astrea. I picked up one very fine 
 specimen, which I have since got cut through and pol- 
 ished. It presents a polygonal partitioning, of a delicate 
 cream-color, that somewhat resembles the cells of a honey- 
 comb. Each cell is filled with a brownish ground of car- 
 bonate of lime ; and on this ground of brown there is a 
 cream-colored stai", comjDosed of rays that proceed from 
 the centre to the sides. One of these corals measured 
 two feet and a half across in one direction, by two feet in 
 another; and if it grew as slowly as some of its order in 
 the present scene of things, its living existence must have 
 stretched over a term of not less extent than that of its 
 contemporary, the pine of the hundred rings. Some of 
 the masses seem as if still adhering to the rocks on which 
 they originally grew ; the pentagonal cells are still open, 
 as if the inhabitants died but yesterday ; and the star-like 
 lines inside still retain their original character of thin par- 
 titions, radiating outwards and upwards from a depressed 
 centre. In other instances they have been torn from their 
 places, and lie upturned in the shale, amid broken shells 
 and fragments of wood. I bi-ought with mc one curious 
 specimen perforated by an ancient pholas. The cavity 
 exactly resembles those cavities of the existing Lithodo- 
 mus shell which fretted so many of the calcareous masses 
 that lay scattered on the beach on every side; but it is 
 shut firmly up by the indurated shale in which the speci-
 
 310 DESCRIPTIVE SKETCHES FROM 
 
 men itself had lain buried, and a fragment of carbonized 
 wood lies embedded in the entrance. The cave is cur- 
 tained across by a wall of masonry, immensely more 
 ancient than that which converted into a prison the cave 
 of the Seven Sleepers. 
 
 RECENT TYPES OF FOSSILS. 
 
 An imagination curious to reerect and restore, finds 
 assistance of no uninteresting kind among the pools and 
 beneath the bunches of sea-weed which we find scattered, 
 at the fall of the tide, over the surface of the Navidale 
 deposits. One very minute pool of sea-water, scarcely 
 thrice the size of a common washing basin, and scarcely 
 half a foot in depth, furnished me with the recent types 
 of well nigh all the fossils that lay embedded for several 
 feet around it ; though there were few places in the bed 
 where these lay more thickly. Three beautiful sea ane- 
 mones — two of crimson, and the third of a greenish-buff 
 color — stretched out their sentient petals along the sides; 
 and the minute currents around them showed that they 
 were all employed in their proper trade of winnowing the 
 water for its animalcular contents, — working that they 
 might live. One of the three had fixed its crimson base 
 on the white surface of a fossil coral ; the pentagonal cav- 
 ities, out of each of which a creature of resembling form 
 had once stretched its slim body and still minuter petals, 
 to agitate the water with similar currents, were lying open 
 around it. In another corner of the pool a sea-urchin was 
 slowly dragging himself up the slope, with all his red 
 fleshy halsers that could be brought to bear, and all his 
 nearer handspikes hard strained in the work. His ])ro- 
 gress resembled that of the famous Russian boulder, trans-
 
 A geologist's portfolio. 311 
 
 ported for so many miles to make a pedestal for the statue 
 of Peter the Great; with this difference, however, that 
 here it was the boulder itself that was plying the hand- 
 spikes and tightening the ropes. And, lo ! from the 
 plane over which he moved there projected the remains 
 of creatures of similar type ; — the rock was strewed with 
 fossil handspikes, greater in bulk than his, and somewhat 
 diverse in form, but whose general identity of character 
 it was impossible to mistake. The spines of echini, fret- 
 ted with lines of projections somewhat in the style of the 
 pinnacles of a Gothic building, lie as thickly in this de- 
 posit as in any deposit of the Chalk itself. The pool had 
 its zoophytes of the arborescent form, — the rock its flus- 
 tra ; the pool had its cluster of minute muscles, — the 
 rock its scallops and ostrea ; the pool had its buccinidae, — 
 the rock its numerous whorls of some nameless turreted 
 shell ; the pool had its cluster of serpulie ; the serpulae lay 
 so thick in the rock, as to compose, in some layers, no 
 inconsiderable proportion of its substance. 
 
 BRORA COAL-FIELD OTHER THAN THE TRUE COAL MEASURES. 
 
 A coal-field in other than the true Coal Measures is 
 always an object of peculiar interest to the geologist ; and 
 the coal-field of Brora is, in at least one respect, one of 
 the most remarkable of these with which geologists are 
 yet acquainted. The seams of the well-known Bovey 
 coal of South Devon — a lignite of the Tertiary — are 
 described as of greater depth ; but it burns so imperfectly, 
 and emits so offensive an odor, that, though used by some 
 of the poorer cottagers in the neighborhood, and some of 
 the local potteries, it never became, nor can become, an 
 article of commerce. It is curious merely as an immense
 
 812 DESCRIPTIVE SKETCHES FROM 
 
 accumulation of vegetable matter jjassing into the mineral 
 state, — as, shall I venture to say, a sort of half-mineralized 
 peat of the Tertiary, — a peat moss that, instead of over- 
 lying, underlies the diluvium. In the Brora coal, as might 
 be inferred from its much greater age, the pi'ocess of 
 mineralization is more complete ; and it furnishes, if I 
 mistake not, the only instance in which a coal newer than 
 that of the carboniferous era has been wrought for cen- 
 turies, and made an article of trade. There were pits 
 opened at Brora as early as the year 1598: they were 
 reopened at various intermediate periods in the seven- 
 teenth and eighteenth centuries ; on one occasion in the 
 middle part of the latter, by Williams, the author of a 
 " Natural History of the Mineral Kingdom," which has 
 been characterized by Lyell as " a work of great merit for 
 its day ; " and during twelve years of the present century, 
 from 1814 to 1826, there were extracted from but a single 
 pit in this field no fewer than seventy thousand tons of 
 coal. The Oolitic coal-field of Sutherland stands out in 
 prominent relief amid the ligneous deposits that derive 
 their origin from the later geological floras. And yet its 
 commercial history does not serve to show that the si^ecu- 
 lations of the miner may be safely pursued in connection 
 with any other than that one wonderful flora which has 
 done so much more for man, with its coal and its iron, 
 than all the gold mines of the world. The Brora work- 
 ings were at no time more than barely remunerative ; and 
 the fact that they were often opened to be as often aban- 
 doned, shows that they must have occasionally fallen 
 somewhat below even this low line. Latterly, at least, 
 it was rather the deficient qualitj of the coal that mili- 
 tated against the speculation, than any deficiency in the 
 quantity found. It burned freely, and threw out a pow-
 
 A geologist's portfolio. 313 
 
 <jrful flame; but it was accompanied by a peculiar odor, 
 that seemed to tell rather of the vegetable of which it 
 had been originally composed, than of the mineral into 
 which it had been converted, and then sunk into a white 
 light ash, which every breath of air sent floating over 
 carpets and furniture. And so, when brought into compe- 
 tition, in our northein ports, with the coal of the Mid- 
 Lothian and English fields, it failed to take the market. 
 The speculation of Williams was singularly unlucky. He 
 became lessee of the entire field about the year 1764, and 
 wrought it for nearly five years. There occurs near the 
 centre of the main seam a band of jayritiferous concre- 
 tions, which here, as elsewhere, have the quality of taking 
 fire spontaneously when exposed in heaps to air and mois- 
 ture, and which his miners had not been sufliciently careful 
 in excluding from the coal. A cargo which he had ship- 
 ped from Portsoy, in Banffshire, took fire in this way, in 
 consequence, it has been said, of the vessel springing 
 a leak ; and such was the alarm excited among his cus- 
 tomers, that they declined dealing with him any longer 
 for a commodity so dangerous. And so, after an ineffec- 
 tual struggle, he had to relinquish his lease. 
 
 LONDON MUSEUM OF ECONOMIC GEOLOGY. 
 
 In the Museum of Economic Geology now in the course 
 of forming in London, there are specimens exhibited of 
 not only the various rude materials of art, furnished by 
 the mine and the quarry, but also of what these can be 
 converted into by the chemist and the mechanic. Not 
 only does it show the gifts of the mineral kingdom to 
 man, but the uses also to which man has applied them. 
 The rough and unpromising block of marble stands side 
 
 27
 
 814 DESCRIPTIVE SKETCHES FROM 
 
 by side with the exquisitely polished and delicately-sculp. 
 tured vase. The bracelet of glittering steel, scarcely of 
 less value than if wrought in gold, ranges in striking con- 
 trast with the earthy, umbiy nodule of clay-ironstone. 
 There are series of specimens, too, illustrative of the 
 various changes which an earth or metal assiwnes in its 
 progress through the workshop or the laboratory. Here, 
 for instance, is the ironstone nodule, — there the roasted 
 ore, — yonder the fused mass ; the wrought bar succeeds ; 
 then comes the rudely-blocked ornament or implement; 
 and, last of all, the exquisitely finished piece of work, as 
 we find it in the cutler's warehouse or the jeweller's shop. 
 I am not aware whether the museum also exhibits its 
 sets of specimens illustrative of substances, elaborated, not 
 by man, but by nature herself; and elaborated, if one may 
 so speak, on the i^rinciple of serial processes and succeed- 
 ing stages. The arrangement in many cases would have 
 to proceed, no doubt, on a basis of hypothesis ; but the 
 cases would also be many in which the hypothesis would, 
 at least, not seem a forced one. It was suggested to rae 
 on the Brora coal-field, that the process through which 
 nature makes coal might be strikingly illustrated in this 
 style. One might almost venture to begin one's serial col- 
 lection with a well-selected piece of fresh peat, containing 
 its fragments of wood, its few blackened reeds, its fern- 
 stalks, and its club-mosses. Another specimen of more 
 solid homogeneous structure, and darker hue, cut from the 
 bottom of some deep morass, might by placed second in 
 the series. Then might come a first specimen of Bovey 
 coal, taken from under its eight or ten feet of Tertiary 
 clay, — a specimen of light and friable texture, and that 
 exhibited more of its original and vegetable qualities than 
 of its acquired mineral ones. A second specimen, brought
 
 A geologist's portfolio. 315 
 
 from a deeper bed of the same deposit, might be chosen 
 by the dai-ker brown of its color, and its nearer approxi- 
 mation to the structure of pit-coal. The Oolitic coal of 
 the Brora or Yorkshire field might furnish at least two 
 specimens more. And thus the collector might pass on, 
 by easy gradations, to the true Coal Measures, and down 
 through these to the deeply-seated anthracite of Ireland, 
 or the still more deeply-seated anthracite of America, — 
 not altogether so assured of his arrangement, perhaps, as 
 in dealing with the processes of the laboratory or the 
 workshop, but at least tolerably sure that both chemists 
 and naturalists would find fewer i-easons to challenge than 
 to confirm it. 
 
 BRORA PEAT-MOSSES OF THE OOLITE. 
 
 The Brora field, so various in its deposits, must have ex- 
 isted in many various states, — now covered by salt water, 
 now by fresh, — now underlying some sluggish estuary, — 
 now presenting, perehance, a superaqueous surface, dark- 
 ened by accumulations of vegetable matter, — and now, 
 again, let down into the green depths of the sea. T& real- 
 ize such a change as the last, one has but to cross the 
 Moray Frith at this point to the opposite land, and there 
 see a peat-moss covered, during stream tides, by from two 
 to three fathoms of water, and partially overlaid by a 
 stratum of sea-sand, charged with its characteristic shells. 
 It is a small coal-bed, kneaded out and laid by, though 
 still in its state of extremest unripeness, — a coal-bed in 
 the raw material; and there are not a few such on the 
 coasts of both Britain and Ireland. Professor Fleming's 
 description of the submerged forests of the Friths of 
 Forth and Tay must be familiar to many of my readers.
 
 316 DESCRIPTIVE SKETCHES FROM 
 
 They must have heard, too, through the far-known "Prin- 
 ciples " of Lyell, of the submerged forests of Lancashire. 
 "In passing over JBlacJc Sod Bay, in a clear, calm morn- 
 ing," says a late tourist in Erris and Tyrawly, "I could 
 see, fathoms down, the roots of trees that seemed of the 
 same sort as are every day dug out of our bogs." Now, 
 we do not know that the Oolite had properly its peat- 
 mosses. The climate, though its pines had their well- 
 marked annual rings, seems, judging from its other pro- 
 ductions, to have been warmer than those in Avhich peat 
 now accumulates ; but there can be no doubt that both it 
 and the true Coal Measures must have had their vast 
 accumulations of vegetable matter^ formed, in many in- 
 stances, on the spot 071 which the vegetable matter grew / 
 and no one surely need ask a better definition of a peat- 
 moss. A peat-moss, in the pi-esent state of things, is sim- 
 ply an accumulation of vegetable matter formed on the 
 spot on which it grew. These, as I have said, we fre- 
 quently find let down on our coasts far beneath the sea- 
 level, and covered up by marine deposits ; and the fact 
 furnishes a first and important step in the proposed serial 
 arrangement of coal in the forming. May I not further 
 add, that Professor Johnston, of Durham, so well known 
 in the field of geological chemistry, regards all our coal- 
 seams, whether of the Carboniferous period or of the Oo- 
 litic, as mere beds of ancient peat, mineralized in the labo- 
 ratory of Nature ? 
 
 QUARRY OF BRAAMBURT UFPER OOLITE, SUTHERLAND. 
 
 On entering the quarry hollowed on the southern emi- 
 nence, one is first struck by the character of the broken 
 masses of stone that lie scattered over the excavations.
 
 A geologist's portfolio. 317 
 
 The rubbish abounds in what seem fragments of a very 
 exquisite sculpture. Tlie shells and lignites, which it con- 
 tains in vast numbei's, exist as mere impressions in the 
 white sandstone, and look as if fresh from the chisel of a 
 Thorn or Forrest. But even these masters of their art 
 would confess themselves outdone here in beauty of finish. 
 Their best works don't stand the microscope ; whereas the 
 carvings of the Uj)per Oolite here, though in sandstone, 
 mightily improve under it. The cast of a broken frag- 
 ment of wood at present before me shows not only the 
 markings of the annual rings, but also the microscoiDic 
 striae of the vegetable fibre, — a niceness of impression 
 impossible in any sandstone that had not what the sand- 
 stones of this quarry have, — a large mixture of calcare- 
 ous cement. I remember that, on my first introduction to 
 the excavations of Braambury, — for such is the name of 
 the quarry, — the vast amount of what seemed broken 
 sculpture in the rubbish reminded me of some of Ten- 
 naut's singularly hapj^y descriptions in his "Dingin down 
 o' the Cathedral." They seemed mememorials of a time 
 when, to the signal detriment of ecclesiastical architecture 
 in Scotland, and all the good solid religion that sjiringa 
 out of sandstone, * 
 
 " nk tirlie-wirlie mament bra, 
 
 That had for centuries ane and a' 
 
 Brankit on bunker or on wa', 
 
 Cam tumblin tap o'er tail * * 
 
 Whan in ilk kirk the angry folk 
 
 Carv't wark, an arch, an pillar broke." 
 
 I had not a few other recollections of the quarry of 
 Braambury. Nothing can be more interesting to the geol- 
 ogist than its fossils, and nothing more annoying, at times, 
 to the workman. Occurring often in the wrought stone, 
 they occasion sad gaps and deplorable breaches, where the 
 
 27*
 
 318 DESCRIPTIVE SKETCHES FROM 
 
 plane should be smooth or the moulding sharp. I remem- 
 ber laying open, on one occasion, a beautiful cast that had 
 once been a belemnite, but that had become a mere cavity 
 in which a belemnite might be moulded, — for even this 
 solid fossil, that so doggedly preserves its substance in 
 most other deposits, is absorbed by the sandstone of 
 Braanibury. And greatly did I admire its peculiar state 
 of keejiing. The smooth, cylindrical hollow was jjartitioned 
 across by two stony diaphragms, thin as bits of drawing- 
 paper ; for ere the absorbing-process had begun, the fossil 
 had been broken into three pieces by the superincumbent 
 weight, and the minute strips of sand which had filled up 
 the cracks had hardened into stone. The point was sharp 
 and smooth ; a rectilinear convex ridge showed the place 
 of the abdominal groove ; a cone at the base, lined trans- 
 versely, represented the chambered shell of the interior. 
 There could not be a more interesting specimen for a 
 museum ; but, alas ! it occupied the jjolished plane of a 
 tombstone, just where the hicjacet should have been; and 
 though it symbolized the sentence wonderfully Avell, it was 
 a symbol which I feared few would succeed in interpreting. 
 I pointed it out to a brother workman, " Ah," said he, 
 "you have got one of these terrrible tangle-holes; they're 
 the dash'dest things in all the quarry." 
 
 Many a curious thing besides does this quarry contain : 
 boles of trees, that look as if sculptured in the white sand- 
 stone, with their gnarled and twisted knots and furrowed 
 rinds ; striated reeds of the same brittle material, that 
 seem the fluted columns of architectural models; club- 
 mosses, with their gracefully-disposed branches; rounded 
 stems, scaled like the cones of the fir ; impressions of fi- 
 brous, sword-shaped leaves, that resemble the leaves of 
 the iris ; and the casts of fragmentary masses of timber.
 
 A geologist's portfolio. 319 
 
 deeply fretted by the involved and tortuous gnawings of 
 some marine worm. Such are a few of the sculptured 
 representations of the flora of the period, — things more 
 delicate by a great deal than those carved flowers of Mel- 
 rose which we And described with such picturesque efiect 
 by Sir Walter, And its fauna we see represented quite as 
 interestingly as its flora. Its sculptured Pectens remind us 
 of those of a Grecian frieze ; a beautifully-ribbed Cardium 
 has proved a still finer subject for the chisel ; its Gryphites 
 stand out in the boldest style of art. One very striking 
 Ammonite (^Aminonite perarmatus) exhibits a double row 
 of prominent cones, that run along the spiral windings, 
 and give to it the appearance of an Ionic volute inge- 
 niously rusticated ; and another Ammonite, that takes its 
 name from the quarry (^Ammonite Uraamburiensis), pre- 
 sents on its smooth, broad sm*face, — for in form it resem- 
 bles some of our recent nautili, — the gracefully-involved 
 lines of the internal partitioning, as sharp and distinct as 
 if traced on copper by the burin. The traveller explores 
 and examines, and finds the rude excavation on the hill- 
 side converted into the studio of some wonderful sculptor. 
 In the quarry opened on the other eminence there are 
 similar appearances presented, but the stone is softer, and 
 the impressions less sharp. 
 
 GLACIERS AND MORAINES OF SUTHERLAND. 
 
 Let us mark the abrupt and imposing character of the 
 hills. They rise dark, lofty, and bare, and show — to em- 
 ploy a graphic Highland phrase — their bones sticking 
 through the skin. They must have been well swept, 
 surely; and as they are composed mainly of Old Red 
 Sandstone conglomerate in this locality, — for we have left
 
 320 DESCRIPTIVK SKETCHES FROM 
 
 behind us the gi'anitio hills of Navidale and Loth, — their 
 sweepings, could we but find them, would have, doubtless, 
 a well-marked character. And now let us turn to appear- 
 ances of another kind. We stand on the polished surface 
 of the rock, with its rectilinear grooves and scratches, and, 
 when we look upioards along the lines, see the mountains 
 and the valley ; but what see we when we look downwards 
 along the lines ? Something exceedingly curious indeed ; 
 — double and triple ranges of miniature hills, composed of 
 boulders and gravel, the veritable conglomerate sweepings 
 of the mountain-slopes and the valley, mixed with sweep- 
 ings of the more distant primary hills that rise behind. 
 There they lie, in lines that preserve such a rude parallel- 
 ism to the steep range from which they were originally 
 scraped, as the waves that rebound from a seaward barrier 
 of cliff maintain to the line of the barrier. Varying from 
 thirty to forty feet in height, and steep and pyramidal, in 
 the cross section, as roofs of houses, they run in contin- 
 uous undulating lines of from a hundred yards to half a 
 mile in length. Three such lines, with their intervening 
 valleys, occur between the base of Braambury Hill and the 
 villnge of Brora, like inner, outer, and middle mounds of 
 circumvallation in an ancient hill-fort. If one steadily 
 rakes, with the edge of one's moist palm, the scattered 
 crumbs on a polished tea-table, they form, of course, into 
 irregular lines, presenting in the transverse section a 
 rudely angular form ; and in the direction in which they 
 have been swept, the moisture from the palm furrows the 
 mahogany with minute streaks of dimness. The illustra- 
 tion is one on the smallest scale possible. But if the palm 
 be tolerably moist, the crumbs tolerably abundant, nnd the 
 polish of the mahogany brought briglitly out, and if we 
 rake into rude parallelism iu tliis way, line after line from
 
 A geologist's portfolio. 321 
 
 the front of some platter or bread-dish, upturned to repre- 
 sent the line of hills, we shall have provided ourselves with 
 no very inadequate model of the phenomena of Braam- 
 bury. But what palm of inconceivable weight, breadth, 
 and strength, could have been employed here in thus 
 raking the debris into lines of hills half a mile in length 
 by at least thirty feet in height, and in pressing into 
 smoothness, as it passed, the asperities of the solid rocks 
 below? The reader has already anticipated the reply. 
 We have before us indications of an ancient glacier, the 
 most unequivocal that are to be found, perhaps, anywhere 
 in the kingdom : there is not a condition or accompani- 
 ment wanting. I have had my doubts regarding glacial 
 agency in Scotland; but, after visiting this locality a 
 twelvemonth ago, I found doubt impossible ; and I would 
 now fain recommend the skeptical to suspend their ulti- 
 mate decision on the point, until such time as they shall 
 have acquainted themselves with the grooved and polished 
 rocks of Braambury, and the parallel moraines that stretch 
 out around its base. 
 
 I had lacked time, during my visit of the previous sea- 
 son, to examine the moraines that lie in the opening of the 
 valley higher up, and now set out to explore them. The 
 day had become exceedingly pleasant. A few cottony- 
 looking wreaths of mist still mottled the hills, and the sky 
 overhead was still laden with clouds ; but ever and anon 
 the sun broke out in hasty glimpses, that went flashing 
 across the dark moors, now lighting up some bosky recess 
 or abrupt clifi", now casting into strong prominence some 
 insulated moraine. The hollow between Braambury and 
 the hills is occupied, as I have said, by an extensive mo- 
 rass, in which the inhabitants of the neighborhood dig 
 their winter fuel, and which we find fretted, in conse-
 
 322 DESCRIPTIVE SKETCHES FROM 
 
 quence, by numerous rectilinear cavities, filled with an inky 
 water, and roughened and darkened on its drier swellings 
 with innumerable parallelograms of peat. I passed an 
 opening in which there were no fewer than five gnarled, 
 short-stemmed fir-trees, laid bare. They lay clustered to- 
 gether, as if uprooted and thrown down by some tremen- 
 dous hurricane, — presenting exactly such appearances as 
 I have seen in the woods of Cromarty after the hurricane 
 of November 1830, when, in less than an hour, three thou- 
 sand full-grown trees were blown down in one not very 
 extensive wood, and lay heaped on some of the more ex- 
 posed eminences in groups of six and eight. A few hun- 
 dred yards from the prostrate trees there rises, amid the 
 morass, a solitary moraine. I could see its gravelly root 
 extending downwards under the peat, which, in the slow 
 course of ages, had accumulated around it, and found the 
 conviction pressing upon me, that, many centuries ago, 
 when the five prostrate pines were living denizens of the 
 forest, and the moss which now enveloped them had not 
 formed, this insulated hill must have raised its heathy 
 ridge over the trees, and borne the marks of an antiquity 
 apparently not less remote than those which it bears now. 
 And then, long ere the hill itself had formed, the same re- 
 mark must have applied, with at least equal force, to the 
 Oolitic rock below. We see that, when overlaid by the 
 ponderous ice, it must have been exactly the same sort of 
 hard, brittle sandstone it is at the present moment. As 
 shown by the slim partitionings that divide internally its 
 casts of Belemnites, it must have hardened ere its fossils 
 were absorbed ; and, as shown by its polished and striated 
 surfaces, its fossils must have been absorbed ere the glacier 
 slid over it. We see laid bare in the lines of the striae, the 
 casts of Gryphites, Pectens, and Terebratula; we see,
 
 A geologist's portfolio. 323 
 
 further, that the hollows which they formed were weak 
 places in the stone, and that the ice, breaking through, had 
 crushed into theiu the minute fragments of wliich their 
 roofs had been composed ; and so infer, from the appear- 
 ances, that the newer Oolite of Sutherland must have been 
 as firm a building-stone in the ages of the glaciers as it is 
 now. 
 
 As we approach the valley of the Brora, we see a long, 
 well-marked moraine sweeping in a curved line along the 
 base of the hill that forms its northern boundary of en- 
 trance, and are again reminded, by the general parallelism 
 of moraine and hill, of the reversed wave thrown back from 
 a barrier of rock. In the gorge of the valley, immediately 
 below where the river expands into a fine wdld lake, we 
 find the moraines very abundant, but jjreserving no regu- 
 larity of line. They exist as a broken, cockling sea of 
 miniature hills ; and, to follow up the twice-used illustra- 
 tion, remind one of rebounding waves at the opening of a 
 rocky bay, where the lines meet and cross, and break one 
 another into fragments. Like many of the other moraines 
 of the Highlands, they were of mark enough to attract the 
 notice of the old imaginative Celtse, who called them Tom- 
 hans, and believed them to be haunts of the fiiiries, — dom- 
 iciles whose enchanted places of entrance might be discov- 
 ered on just one night of the year, but which no man, not 
 desirous of becoming a denizen of fairyland, would do well 
 to enter. The lake above is a fine, lonely sheet of water, 
 fringed with birch, and overlooked by many a green, unin- 
 habited spot, dimly barred by the plough. A range of 
 stern, solemn-looking hills rise steep and precipitous on 
 either hand ; while a single picturesque hill, with abrupt 
 sides and a tabular summit, terminates the upward vista 
 some six or eight miles away. I saw in one reedy bay a
 
 324 DESCRIPTIVE SKETCHES FROM 
 
 whole community of water-lilies opening their broad white 
 jsetals and golden stamens to the light ; and, wishing to 
 possess myself of one that grew nearer the shore than any 
 of the others, and having no such companion as Cowper's 
 dog Beau to bring it me, I cut a long switch of birch, and 
 struck sharply at the stem, that I might decapitate it, and 
 then steer it to land. But the blow, though repeated and 
 re-repeated, fell short ; and I had drawn my last, when up 
 there started from the bottom a splendid lily, two-thirds 
 developed, — a true Venus, that, rising from the water, 
 looked up to the light, neck-deep, with the rest. The agi- 
 tation occasioned by the strokes had burst the calix, and, 
 true to its nature, up the prematurely-liberated flower had 
 sprung. The image which the incident furnished mingled 
 curiously with my attempted restorations of the ancient 
 state of the valley. The delicate lily, rising to the surface 
 in its quiet, sheltered bay, during a bright glimpse of sun- 
 shine, formed an interesting point of contrast to what 
 seemed a vast foaming river of ice, that rose on the hill- 
 sides more than half their height, and swept downwards, 
 till where it terminated in the plain, in an abrupt moving 
 precipice, that ploughed before it, in its irresistible march, 
 huge hills of gravel and stone. 
 
 LEVEL STEPPES OF RUSSIA, AND THEORY OF MORAINES. 
 
 In the level steppes of Russia, where the traveller may 
 journey without seeing a hill for weeks together, the rocks 
 have their grooved and polished surfaces. And even in 
 localities where there are hills, the hills not unfrequently 
 merely add to the difficulty. The lofty top of Schehallien, 
 for instance, is grooved and polished ; and, pray, from what 
 neighboring eminence could the glacier have descended on 
 it? Extreme, however, as the difficulties that environ the
 
 A geologist's portfolio. 325 
 
 phenomena may seem, they hiive been manfully met by 
 Agassiz, and dealt with in a style in which only a man of 
 genius could have dealt with anything. And if difficulties 
 still attend his theory, there are at least other difficulties 
 which it ingeniously obviates ; and it seems but right, at 
 all events, to give it generous entertainment and a f;iir 
 trial, until such time as it may be found untenable, or until 
 at least something better turns up to set in its place. 
 
 The flat steppes of Russia have, I have said, their groov- 
 ings and polishings : they have also theii' moraine ; and so 
 enormous is the extent of the lattei*, that for week after 
 week the traveller may find it stretching through the cen- 
 tral wilds of the empire, on and on, without apparent ter- 
 mination, by North Novogorod towards Pinsk, as far as 
 the confines of Silesia. It exists as a broad belt of erratic 
 blocks, mingled with heaps of gravel, and resembles, from 
 its linear continuity, the scattered remains of some such 
 vast wall as that which protected of old the Chinese fron- 
 tier from the Tartar. And here, says Agassiz, is the mo- 
 raine of a glacier that had for its centre no group of local 
 eminences, no vanished Alps of the Frozen Ocean, but the 
 North Pole itself The ice of the Southern Pole advances 
 as fai-. Could we but reverse the conditions of the two 
 poles, the northern icy barrier would extend to the English 
 Channel, and the whole British islands would lie enveloped 
 in one vast glacial winding-sheet, that, overlying the sum- 
 mits of our hills, Avould furrow with its parallel strice even 
 the granitic top of Schehallien. 
 
 A complete reversal of the conditions of the two poles 
 would account, doubtless, far many of the phenomena 
 existing in connection with the boulder-clay, which seem 
 otherwise so inexplicable. But is the reversal itself pos- 
 sible ? A Laplace or Lagrange could perhaps answer the 
 
 28
 
 326 DESCRIPTIVE SKETCHES FROM 
 
 question. Tliis much, however, men of lower attainments 
 may know, — that the meteorological condition of the 
 two poles are very different, — the icy barrier advancing, 
 in the case of the one, many degrees nearer the equator 
 than it does in the case of the other ; that their astronom- 
 ical condition is also very different, the sun being many 
 millions of miles nearer tlie one in winter, and nearer the 
 other in summer. It may be known, further, that these 
 astronomical conditions are in a state of gradual change ; 
 that, so far at least, as human observation extends, the 
 change has been steadily pi-ogressing in one direction ; 
 that, should it but continue, a time must inevitably arrive 
 when their astronomical circumstances shall be wholly re- 
 versed, — a time when the sun shall look down upon our 
 northern hemisphere in a^phelion in winter, and in perihe- 
 lion in summer. True, we do not yet know that the me- 
 teorological differences of the poles depend on their astro- 
 nomical differences, or whether the gradual diminution in 
 the eccentricity of the earth's orbit, which has been lessen- 
 ing these latter differences ever since astronomers regis- 
 tered their observations, may not be like the change in the 
 ecliptic, — the result of mere oscillation, limited to a few 
 degrees. 
 
 Let us, however, conclude the case to be otherwise : let 
 us deem the oscillations in the earth's orbit to be so great 
 as to involve an alternate progress in the sun, between his 
 two foci; let us further infer a dependence between his 
 place in each and the meteorological condition of the 
 poles. We stand, let us suppose, on the summit of a hill ; 
 but, as if an immense wedge had been thrust between our 
 feet and the soil, we i-ise to a higher elevation on an in- 
 clined plane of ice, and look over a frozen continent, 
 enlivened by no winding arms of the sea, and bounded 
 by no shore. In the words of Coleridge,
 
 A geologist's portfolio. 327 
 
 " The ice is here; the ice is there; 
 The ice is all around ; 
 It cracks, and growls, and roars, and howls, 
 A wild and ceaseless sound." 
 
 It is summer; and the sun, in perihelion^ looks down with 
 intense ghire on the rugged surface. There is a ceaseless 
 dasli of streams that come leaping from the more exposed 
 ridges, as they shrink and lessen in the heat, or patter from 
 the Kunlit jjinnacles, like rain from the eaves of a roof in a 
 thun<ler-shower. They disappear in cracks and fissures; 
 and we may hear the sound, rising fiom where they break 
 themselves, far beneath, in chill caverns and gloomy re- 
 cesses, where, even at this season, at noon, tiie tempera- 
 ture rises but little above the freezing-point, and sinks far 
 beneath it every evening as the sun declines. The night 
 shall scarce have come on when all these water-courses 
 shall be bound up by the frost, and the melted accumula- 
 tions which they precij^itated into the fissures beneath 
 shall be converted into expansive wedges of ice, under the 
 influence of which the whole ice-continent shall be moving 
 slowly onwards over the buried land. Millions of millions 
 of wedges shall ply their work during the night on every 
 square mile of surface, and the coming day shall j^repare 
 its millions of millions more. There is thus a slow but 
 steady motion induced towards the open space where the 
 huge glacier terminates ; the rocks far below grind down 
 into a clayey paste, as the ponderous mass goes crushing 
 over them, — deliberate, when at its quickest, as the hour- 
 band of a time-piece, — and vast fragments are borne away 
 from submerged peaks and precipices by the enclasping 
 solid, just as ordinary streams bear along their fragments 
 of rock and stone from the banks and ridsres that lie most
 
 328 DESCRIPTIVE SKETCHES FROM 
 
 exposed to the sweep of their currents. All around, ac- 
 cording to Milton, 
 
 " A frozen continent 
 Lies dark and wild, beat by perpetual storms." 
 
 Not a peak of our higher hills appears : all are enveloped 
 in their cerements of cold and death. Even along the 
 flanks of the gigantic Alps, the groovings and polishings 
 rise, says Agassiz, to an elevation of nine thousand feet; 
 and then, and not before, do we find the pinnacles that 
 overlooked the scene standing up sharp and unworn. If 
 we ask a varied prospect, we must remove from our pres- 
 ent stand, to where Mont Blanc and his compeers raise 
 their white summits over the line of the horizon, to give 
 earnest of a buried continent, or to where the smoke and 
 fire of Hecla ascends amid the level from a dripping crater 
 of ice. 
 
 CKOMAETT, 
 
 Cromarty, — my own especial m an oi", which I have so 
 often beat over, but not yet half exhausted, — presents to 
 the geologist one of the most interesting centres of explor- 
 ation in Scotland. Does he wish thoroughly to study our 
 fcotch Lias, Upper and Lower, with the Oolitic member 
 hich immediately overlies it? — then let him remove to 
 Cromarty, and study it there. Is he solicitous to acquaint 
 himself with the fossils of the Lower^ Old Red Sandstone 
 in that state of finest preservation in which the microscope 
 finds most of beauty and finish in them? — then let him 
 by all means settle at Cromarty. Is he wishful of know- 
 ing much about the last elevated of our granitic hill 
 
 1 Now ascertained to be Middle.
 
 A geologist's portfolio. 329 
 
 ranges, — a range newer, apparently, than many of our 
 south-country traps? — let him not hesitate to take lodg- 
 ings at Cromarty. Is he curious regarding our boulder- 
 clay ? — let him set himself carefully to examine the splen- 
 did sections which it presents in the neighborhood of 
 Cromarty. Does he feel aught of interest in our raised 
 beaches? — then let him come and live upon one at Ci'o- 
 marty. Is he desirous of furnishing himself with a key 
 to the geology of the north of Scotland generally ? — in 
 no place will he be able to jDossess himself of so covaYAete 
 a key as among the upturned strata of Cromarty. Had 
 he to grope his way along a course of discovery, he might 
 find the district yielding up its more interesting phenom- 
 ena but slowly. To know its Lias deposits thoroughly 
 would be a work of months, and to know its Old Red 
 Sandstone, a Avork of years; but with some intelligent 
 guide to point out to him the localities to which his atten- 
 tion should be directed, and all in them that has been 
 done and observed already, he would find that much 
 might be accomplished in the course of a single week, — 
 especially in the long calm days of July, when the more 
 exposed shores of the district, with all their insulated 
 stacks and ledges, and all their deep-sea caves, may be 
 explored by boat. 
 
 CAVES OF CROMARTY, OR THE ART OF SEEING OVER THE 
 ART OF THEORIZING. 
 
 We swept ownwards through the noble opening of 
 the Cromarty Frith, and landed under the southern Sutor, 
 on a piece of rocky beach, overhung by a gloomy semi- 
 circular range of precipices. The terminal points of the 
 range stand so far out into the sea, as to render inacces- 
 
 28*
 
 830 DESCRIPTIVE SKETCHES FROM 
 
 sible, save by boat, or at the foil of ebb in stream tides, 
 the piece of crescent-shaj3ed beach -within. Each of the 
 two j^roniontories is occupied by a cave in which the sea 
 at flood stands some ten or twelve feet over the gravel 
 bottom, and there are three other caves in the semicircle, 
 into which the tide has not entered since it fell back from 
 the old coast line. The larger and deeper of the three 
 caves in the semicii'cular inflection is mainly that which 
 we had landed to ex2)lore. It runs a hundred and fifty 
 feet into the granitic i*ock, in the line of a fiixdt that seems 
 first to have opened some eight or ten feet, and then, lean- 
 ing back, to have closed its sides atop, forming in this way 
 a long angular hollow. It has borne for centuries the 
 name of the JDoo-cot, i. e. Dove-cot., Cave, and has been 
 from time immemorial a haunt of pigeons. We approach 
 the opening. There is a rank vegetation springing up iiT 
 front, where the precipice beetles over, and a small streanj 
 comes pattering in detached drops like those of a thundei- 
 shower; and we see luxuriating under it, in vast abun- 
 dance, the hot, bitter, fleshy-leaved scurvy-grass, of Avhich 
 Cook made such large use, in his voyages, as an anti-scor- 
 butic. The floor is damp and mouldy ; the green ropy 
 sides, which rise some five-and-twenty feet ere they close, 
 are thickly furrowed by ridges of stalactites, that become 
 purer and whiter as we retire from the light and the vege- 
 tative influences, and present in the deeper recesses of the 
 cave the hue of statuary marble. The last vegetable that 
 appears is a minute delicate moss, about half an inch in 
 length, which slants outwards to the light on the pi'omi- 
 nence of the sides, and overlies myriads of similar sprigs 
 of moss, long since converted into stone, but which, faith- 
 ful in death to the ruling law of their lives, still point, like 
 the others, to the fi-ee air and sunshine. As we step on-
 
 A geologist's portfolio. 331 
 
 wards, we exchange the brightness of noon for the mel- 
 lower light of evening. A few steps further, and evening 
 has deepened into twilight. We still advance : and twi- 
 light gives place to a gloom dusky as that of midnight. 
 We grope on, till the rock closes before us ; and, turning 
 round, see the blue waves of the frith through the long, 
 dark vista, as if we viewed them through the tube of some 
 immense telescope. We strike a light. The roof and 
 sides are crusted with white stalactites, that depend from 
 the one like icicles from the eaves of a roof in a severe 
 frost, and stand out from the other in pure, semi-transpar- 
 ent ridges, that resemble the folds of a piece of white 
 drapery dropped from the roof; while the floor below has 
 its rough pavement of stalagmite, that stands up, wherever 
 the drops descend, in rounded prominences, like the bases 
 of columns. The marvel has become somewhat old-fash- 
 ioned since the days when Buchanan described the drop- 
 ping cave of Slains, — " where the water, as it descends 
 drop by drop, is converted into pyramids of stone," — as 
 one of the wonders of Scotland, and deemed it necessary 
 to strengthen the credibility of his statement by adding, 
 that he had been "informed by persons of undoubted 
 veracity that there existed a similar cave among the Pyj'- 
 enees." Here, however, is a j^uzzle to exercise our ingenuity. 
 Some of the minuter stalactites of the roof, after descend- 
 ing perpendicularly, or at least nearly so, for a few inches, 
 turn up again, and form a hook, to which one may sus- 
 pend one's watch by the ring ; while there are others that 
 form a loop, attached to the roof at both ends. Pray, how 
 could the descending drop have returned upwards to form 
 the hook, or what attractive power could have drawn two 
 drops together, to compose the eliptical curve of the loop ? 
 The problem is not quite a simple one. It is sufficiently
 
 332 DESCRIPTIVE SKETCHES FROM 
 
 hard at least, as it has to deal with only half-ounces oi 
 rock, to inculcate caution on the theorists who profess to 
 deal with whole continents of similar material. Let us 
 examine somewhat narrowly. Dark as the recess is, and 
 though vegetation fails full fifty feet nearer the entrance 
 than where we now stand, the place is not without its 
 inhabitants. We see among the dewy damps of the roof 
 the glistening threads of some minute spider, stretching 
 in lines or depending in loops. And just look here. Along 
 this loo}) there runs a single drop. Observe how it de- 
 scends, with but a slight inclination, for about two inches 
 or so, and then turns round for about three quarters of an 
 inch more ; observe further, that along this other loop 
 there trickle two drops, one on each side; that, as a conse- 
 quence of the balance which they form the one against the 
 other, their descent has a much greater sweep ; and that, 
 uniting in the centre, they fall together. We have found 
 a solution of our riddle, and received one proof more of 
 the superiority of the simple art of seeing over the ingen- 
 ious art of theorizing. 
 
 But let us jDroceed to the proper business of the excur- 
 sion. We have provided ourselves with tools for digging; 
 and, selecting a spot some thirty feet within the cavern, 
 where the bottom seems composed of a damp dark mould, 
 we set ourselves, with spade and pick-axe, to penetrate 
 to the sea-gravel beneath. The soil yields as easily to the 
 tool as a piece of garden mould; and, turning it up to the 
 light in cubical adhesive masses, we find it consisting of 
 an impalpable brown earth, that exactly resembles raw 
 umber. We have fallen on a bed of pure guano, not 
 quite so rich, ])erhaps, as that which our agriculturists 
 export from the rocky islets of South America, at the rate 
 of about foui;teen pounds per ton, for it must have been
 
 A geologist's portfolio. 333 
 
 formed originally of vegetable, not animal matter, and we 
 find that it lacks the strong ammonical smell of the guano 
 produced by predacious water-birds ; but, judging from 
 its appearance, and from the high estimate formed of old 
 of the dung of pigeons as a manure, it must be of value 
 enough to deserve removal fi'om the damp unproductive 
 floor of the Doo-cot. We find the bed which it com- 
 poses extending downwards from two to three feet, and 
 filling the cavern from side to side. A rock-gravel lies 
 below, hardened into an imperfect breccia by a ferrugin- 
 ous cement; but the rotting moisture exuded from the 
 guano has been unfavorable, apparently, to the preserva- 
 tion of the shells, and we find that it contains nothing 
 organic. We again remove to the inner recesses of the 
 cave. Mark first, that peculiar appearance along the sides. 
 There stands out, at the height of about four feet from 
 the present floor, what seems a rude projecting cornice of 
 rock-gravel, bound together by the stalactitical cement : 
 the projection at one point somewhat exceeds eighteen 
 inches ; and we find it bearing short-stemmed stalagmites 
 atop, just like the rugged pavement below. To use a 
 homely but ajjt illustration, the appearance is that pre- 
 sented by the lower part of a tallow-candle that had been 
 burning, exposed to a current of air, with its grease run- 
 ning down in ridges on the sides, and then spreading out 
 on the margin of the metal socket, when, after raising it 
 out of the candlestick, we see the lower accumulation pro- 
 jecting from it like a cornice. That line of projecting 
 gravel indicates the level at which the floor of the cavern 
 once stood. If we remove the looser parts of the present 
 floor, we shall find its place indicated by just a similar line 
 of projection. The loose sea-gravel could have adhered 
 to the sides only by having formed the part of the floor in
 
 334 DESCRIPTIVE SKETCHES FROM 
 
 contact with them, until the stalagmitical substance had 
 taken effect upon it, by binding it into a mass, and fixing. 
 it where it had lain. Let us break into one of the projec- 
 tions. We find it a true breccia, thickly interspersed with 
 such fragments of shells as we may pick up by hundreds 
 in the neighboring sea-caves, where the incessant beat of 
 the surf on the liard rocks against which it dashes breaks 
 them into rounded fragments. There, for instance, is a 
 massy little bit of the strong smooth buckie, [Fusus An- 
 tiquus), the largest of British univalves ; and there a frag- 
 ment equally massy of the Icelandic Venus, — both of 
 them productions of the oceans, and of such rivers as the 
 Friths of Cromarty and Dornoch. The materials of the 
 projecting cornice are those of a cavern-beach much ex- 
 posed to the roll of the surf. 
 
 Let us now see what our several points of circumstan- 
 tial evidence amount to. First, then, the bottom of the 
 cave must have stood at one time at least four feet over 
 its present level, and at least fourteen feet over the level 
 of the two sea-caves outside ; and yet, just as the sea now 
 covers them, must the sea at that remote pei-iod have 
 covered it. The incessant wave must have resounded 
 along these silent walls as it dashed sullenly onwards, and 
 awakened all their echoes with its harsh rattle as it rolled 
 back. The cavern at that early time, like all the other 
 deep-sea caves of the coast, could have had no crust of 
 stalactites. Its sides and roof must have been as dark and 
 bare as the sides and roofs of the caves outside, where the 
 spray washes away every film of calcareous matter ere it 
 has been deposited for half a day. A sudden elevation 
 of the coast took place, and sudden it must have been, for 
 the loose gravel beach, with its finely comminuted shells, 
 was at once raised beyond the influence of the tides; the
 
 A geologist's portfolio. 335 
 
 stalactitical ridges began to fcfrm on the walls, and the 
 sea-gravel to consolidate — where these terminated be- 
 neath, and the petrifying water oozed through — into the 
 breceiated cornice. But the waves from the lower line 
 had been encroaching inwards, bit by bit, from the cavern's 
 mouth, washing down the floor to their own reduced level, 
 until they had at length scooped it all out, and left but 
 the hardened projections to mark where it had stood. 
 The cave, though now occupied by only the higher tides, 
 had again become, in some sort, a sea-cave, when a second 
 elevation of the land raised it to its present level. The 
 covering of stalactites thickened along its sides; its minute 
 mosses lived, died, and became marble ; and, as age suc- 
 ceeded age, the dark recesses in its roof were cheered by 
 the unerring affections of instinct ; and brood after brood, 
 reared with assiduous labor to maturity, went forth, some 
 again to return to their hereditary cells, some to take up 
 their abodes with man. I need scarce say, that the rock, 
 or white-backed dove, is the original of our domestic 
 species. 
 
 LINE OF CROMARTY SUTOR. 
 
 We find that there leaned against one of the precipices 
 of the Southern Sutor, now washed by the spring tides, a 
 talus of loose debris, such as we see still leaning against 
 the precipices of the old coast line, and that a calcareous 
 spring, dropping upon it from an upper ledge, had, in the 
 course of years, converted its apex into a hard breccia and 
 cemented it to the rock, while the base below remained 
 incoherent as at first. During this period it must have 
 lain beyond the sweep of the waves. But a change of 
 level took place ; the waves came dashing against the 
 loose debris, and swept it away ; and all that now remains
 
 336 DESCRIPTIVE SKETCHES FROM 
 
 of the talus is the consolidated apex, projecting about 
 three feet from the rock. Under another precipice of the 
 Cromarty Sutor we find a line of consolidated debris — 
 which, like the breccia of the apex, must have been the 
 work of a calcareous spring — running out about fifty feet 
 into the ebb, where it is altogether impossible it could 
 have formed now. The spring must have flowed down- 
 wards for these fifty feet ere it reached the sea; for no 
 sooner could it have touched the latter than its waters 
 would have been diflTused and lost ; and, even could they 
 have avoided such diflfusion, the Avaves must have pre- 
 vented the loose gravel on which the calcareous matter 
 acted from remaining sufiiciently stationary for a' single 
 tide. In each of these cases is the value of the evidence 
 enhanced by the circumstances in Avhich it is given. Both 
 the talus and the brecciated line were formed on a basis 
 of gigantic rock, so hard that it strikes fire with steel, and 
 which only a general change of level could have let down 
 to the influence of the tide, or elevated over it. 
 
 LESSON TO YOUNG GEOLOGISTS FROM CLAY-BED OF THE 
 NORTHERN SUTOR. 
 
 There is a stiflT, blue clay much used in Cromarty and the 
 neighborhood for rendering the bottom of ponds water- 
 tight, and the foundations of cellars impervious to the 
 land-springs, and which, save for its greater tenacity, much 
 resembles the blue boulder-clay of our Coal Measures. It 
 is found in the ebb at half-tide, in a bed varying from 
 eighteen inches to three feet in thickness, which overlies 
 the red boulder-clay, and contains minute fragments of 
 shells, too much broken to be distinguished. I had deemed 
 it a sort of re-formation from strata of a grayish-colored
 
 A geologist's portfolio. 337 
 
 aluminous shale, Avhich occur in the Old Red Sandstone, 
 and are laid bare in the neighborhood by the sea. The 
 waves dash against them, and then roll back turbid with 
 the lighter particles, to deposit these in the deep, still 
 water outside. But in the place at present occupied by 
 the bed the waves could not have deposited them ; it is so 
 much exposed to the surf, that the deposit is gradually 
 wearing down under the friction, and it must have been 
 formed, therefore, at a lower level, and Avhen the sea beat 
 against the ancient beaches. We find further proof that 
 such must have been the case in a soft stratum of gray, 
 shaly sandstone, which rises through the bed, and which 
 is thickly perforated by cells of the Pholas candicliis, con- 
 taining in abundance the dead shells, but which has been 
 elevated to a too high place to form any longer a fit habitat 
 for the living animals. I had often examined the frasf- 
 mentary shells of this clayey layer, in the hope of being 
 able to elicit from them somewhat regarding the history 
 of a deposit older than our present coast line, yet newer 
 than our boulder-clay ; but I had hitherto found them in 
 every case too comminuted to yield the necessary evi- 
 dence. I now succeeded, however, in detecting the same 
 deposit under the Northern Sutor, in the same close neigh- 
 borhood as on the Cromarty side to the gray aluminous 
 shale of the Old Red Sandstone, to which it seems to have 
 owed its origin, and abounding in organisms marine and 
 terrestrial. All are recent. I found it containing cones 
 of our common Scotch fii-, hazel-nuts, fragments of alder 
 and oak, shells of the common mussel much decomposed, 
 and shells, too, of one of the Gaper family {3Iyce are- 
 naria\ still lying in pairs. The blue, adhesive clay in 
 which they are embedded can scarce be distinguished 
 from that of the Lower Lias of Eathie ; the sets of organ- 
 
 29
 
 338 DESCRIPTIVE SKETCHES FROM 
 
 isms in the two deposits are also the same, — indicating 
 that tlieir deposition must have taken place under similar 
 conditions. The Lias, like the recent clay, has its cones, 
 its bits of wood, and its marine bivalves lying in pairs; 
 and the sole difference that obtains between them is, that 
 while the cones, and wood, and bivalves of the blue clay 
 are all existences of the present time, the cones, and wood, 
 and bivalves of the Lias represent classes of organic beings 
 that have long since passed into extinction. This clay- 
 bed of the Northern Sutor is one of the best places I know 
 for the young geologist taking his first lesson upon. I 
 deemed it of interest chiefly as corroborative of the fact 
 that our raised beaches on the shores of the Cromarty 
 and Moray Friths belong to exactly the present state of 
 things ; nay, that for a very inconsiderable period ere 
 their elevation, when the blue bed was forming in com- 
 paratively deep water, both sea and land were stored with 
 their existing productions. 
 
 GLACIAL APPEARANCES AT NIGG AND LOGIE. 
 
 There are two several localities in which, after acquaint- 
 ing one's-self with the glacial moraines of Brora, one may 
 examine with advantage the glacial moraines of the neigh- 
 borhood of Cromarty. One of these we find in the parish 
 of Logic, not a hundred yards distant from the great 
 coach road ; the other, in the parish of Nigg, on one of 
 the slopes in which the lofty ridge, whose south-western 
 termination forms the northern Sutor, sinks at its north- 
 eastern boundary into the i:)lain of Easter Ross. The 
 Logie moraine extends, for full three-quarters of a mile, 
 in a line parallel to the mountain range from which its 
 glacier must have descended. There is a furzy level in
 
 A geologist's portfolio. 339 
 
 front, mottled over with groups of cottages ; the moraine, 
 — thickly planted with fir, and amid whose sheltering 
 hollows the gipsies' tent may be seen in the warmer 
 months, and the houseless Free Church congregation at 
 this inclement season, — forms a long undulating ridge, 
 in what a painter would terra the middle ground of the 
 landscape ; while on the swelling acclivities behind, over 
 which the icy plane must have once extended, we see 
 woods, and fields, and stately manor-houses, and, high 
 above all, the heathy mountain ridge, where the sky 
 seems resting on the land. I have not seen the rock laid 
 bare in any jjart of the cultivated tract which intervenes 
 between the moraine and the upland ridge ; but I enter- 
 tain little doubt that its surface will be found to bear the 
 characteristic groovings and polishings of the glacial period. 
 The moraines of the Hill of Nigg, as might be premised, 
 from the lower elevation and narrower slopes of the em- 
 inence from which their glacier descended, are of small 
 extent, compared with the moraine of Logic. There is, 
 however, one of the number, a beautiful grassy Tomhan, 
 fringed at the base with its thickets of dwarf-birch and 
 hazel, that was deemed commanding enough in some 
 early age, to be selected as the site of a hill-fort, still 
 known to tradition as the Danish camp, and whose double 
 mound of turf we may still see encircling the summit. It 
 must have been a dreary period when the great glacier of 
 Logic, sloping towards the south, and the lesser glacier 
 of the hill of Nigg, sloping towards the north, saw them- 
 selves reflected in the separating strait of sea which at 
 this remote period flowed through the flat valley be- 
 tween. The valley is still occupied for half its length by 
 a sandy estuary, known as the Sands of Nigg, which, ere 
 the upheaval of the higher beaches, must have existed as a
 
 340 DESCRIPTIVE SKETCHES FROM 
 
 shallow channel, through which the Frith of Cromarty — 
 then a double-mouthed arm of the sea, with the hill of 
 Nigg as a mountainous island in the midst — commuui- 
 cated with the Moray Frith beyond. 
 
 PHENOMENA EXPLANATORY OF ACCUMULATIONS OF SHELLS. 
 
 There are scarce any of the appearances with which the 
 geologist is conversant more mysterious than the immense 
 accumulations of shells which he occasionally finds, as in 
 some parts of Sweden, separated from all extraneous mat- 
 ter, as if they had been subjected to some sifting process, 
 — cleaned, as it were, and laid by ; and it has long been 
 a question with him how this sifting process had been 
 effected. The theory that the accumulation had been 
 heaped up by great floods, through Avhich substances of 
 the same specific gravity were huddled together, has been 
 the commonly accepted one; but who ever saw a flood, 
 however great, that did not cast down its mud and its 
 clay among its transported shells, or that had not mingled 
 them, in the process of removal, with its lighter gravels or 
 its sand ? In the flat estuary of Nigg, I have seen the 
 sifting process effected through a simple but adequate 
 agency. For about two miles from where the estuary 
 opens into the Cromarty Frith, its wide tracts of yielding 
 sand are thickly occupied by the shells that love such lo- 
 calities, — in especial, by the common cockle. Almost 
 every tide, when the animals are in season, furnishes its 
 vast quantities for the markets of the neighboring tOAvns, 
 and still the supply keeps up ample as at first. Now the 
 tracts of sand which they inhabit, if not properly quick- 
 sands, are at least extremely loose, especially when cov- 
 ered by the tide; and though the creatures succeed, so
 
 A geologist's portfolio. 341 
 
 long as they live, in maintaining their proper place in them, 
 within a few inches of the surface, no sooner do they die 
 than the shells begin gradually to sink downwards through 
 the unsolid mass, till, reaching, at the depth of about six 
 feet, a firmer stratum, they there accumulate, and form a 
 continuous bed. The work of accumulation has been going 
 on for many centuries ; generation after generation has 
 been dying, to undergo this process of burial, — this pro- 
 cess of subarenaceous deposition, if 1 may so speak ; and 
 there are places in the estuary in which the shelly stratum 
 has risen to within a foot or two of the surface. It forms 
 a sort of quarry of shells ; and when, about thirty years 
 ago, thei-e was a lime-work established in the neighbor- 
 hood, many thousand cartloads were dng out and burnt 
 into lime. I had frequent occasion, some five or six years 
 since, to pass through the estuary at seasons when the 
 mere amateur would have perhaps staid at home. There 
 runs through it a stream of fresh water, that drains the flat 
 fields and scattered lochans of Easter Ross ; and on one 
 of my winter journeys, after a sudden thaw, accompanied 
 by heavy rains, I found the stream swollen to the size of a 
 considerable river, and its bed excavated beneath the usual 
 level some three or four feet, with the sectional line of 
 sand and shells through which it had cut standing up over 
 it like a wall. There was first, reckoning downwards, from 
 a foot to eighteen inches of pure sand ; and next, from two 
 feet to two feet and a half of dead shells. The sandy 
 tract all around, for many hundred acres in extent, used 
 to be pai'tially covered with water ; every furrow of the 
 ripples, and every depression of the surface, borrowed its 
 full from the receding tide, and, from the general flatness, 
 retained it till its return. But on this occasion, the sur- 
 face-water had found an unwonted drainasre, through the 
 
 29*
 
 342 DESCRIPTIVE SKETCHES FROM 
 
 upright sectional front, into the newly excavated bed of 
 the stream. It sank through the uj^per arenaceous layer 
 as through a filtering stone, and then came rushing through 
 the stratum of shells underneath, brown with the sand 
 which it swept from their interstices. Nor could there be 
 a completer sifting process. For yards and roods together 
 the shells were as thoroughly divested of the sandy ma- 
 trix in which they had lain as if they had been carefully 
 washed in a sieve. I was bold enough to infer from the 
 phenomenon at the time, that the problem of the unmixed 
 accumulation of shells may be, in at least some cases, not 
 so difficult of solution as has been hitherto supposed. One 
 has but to take for granted conditions such as those of the 
 estuary of Nigg, — the incoherent bed, half a quicksand, 
 and the subarenaceous deposition, — to account for their 
 original production, and the superadded conditions of the 
 surface-water and the free drainage, to account for their 
 after clearance of extraneous matter. 
 
 CAUTION TO GEOLOGISTS ON THE FINDING OF REMAINS. 
 
 In consolidated slopes it is not unusual to find remains, 
 animal and vegetable, of no very remote antiquity. I 
 have seen a human skull dug out of the reclining base of 
 a clay bank, once a precipice, fully six feet from imder the 
 surface. It might have been deemed, not without a de- 
 gree of plausibility, the skull of some long-lived contem- 
 porary of Enoch, — perchance that of one of the accursed 
 race, 
 
 " Wlio sinned and died before the avenging flood." 
 
 Nay, a fine theory was in the act of being formed regard- 
 ing it, which aflfected the whole deposit; but, alas! the
 
 A geologist's portfolio. 343 
 
 laborer dug a little further, and struck his pickaxe against 
 an old Gothic rybat, that lay deeper still. There could be 
 no mistaking the character of the champfered edge that 
 still boi-e the marks of the tool, nor that of the square per- 
 foration for the lock-bolt ; and the rising theory straight- 
 way stumbled against it and fell. Both rybat and skull 
 had come from an ancient burying-ground, situated on a 
 projecting angle of the table, and above. 
 
 BEMARKS ON UNDERLYING CLAY ON LEVEL MOORS. 
 
 On level moors, where the rain-water stagnates in pools, 
 and a thin layer of mossy soil produces a scanty covering 
 of heath, we find the underlying clay streaked and spotted 
 with patches of white. As in the spots and streaks of the 
 Red Sandstone formations. Old and New, the coloring 
 matter has been discharged without any accompanying 
 change having taken place in the mechanical structure of 
 the substance which it pervaded ; for we find the same 
 mixture of arenaceous and aluminous particles in the white 
 as in the red portions. And the stagnant water above, 
 acidulated, perhaps, by its various vegetable solutions, 
 seems to have been in some way connected with these ap- 
 pearances. In almost every case in which a crack through 
 the clay gives access to the oozing moisture, we find the 
 sides bleached, for several feet downwards, to nearly the 
 color of pipe-clay ; we find the surface, too, when divested 
 of the soil, presenting for yards together the appearance 
 of sheets of half-bleached linen. Now, the peculiar chem- 
 istry through which these changes are eflfected might be 
 found to throw much light on similar phenomena in the 
 older formations. There are quarries in the New Red 
 Sandstone in which almost every mass of stone presents
 
 344 DESCRIPTIVE SKETCHES FROM 
 
 a different shade of color from that of its neishborinjr 
 mass, and quarries in the Old Red, whose strata vre find 
 streaked and spotted like pieces of calico. And their 
 variegated aspect seems to have been communicated in 
 every instance, not during deposition, nor after they had 
 been hardened into stone, but when, like the boulder-clay, 
 they had existed in an intermediate state. 
 
 TRAVELLED BOULDERS NOT ASSOCIATED WITH CLAY. 
 
 All the travelled boulders of the north do not seem asso- 
 ciated with the clay. We find them occurring, in some in- 
 stances, in an overlying gravel, and in some instances rest- 
 ing at high levels on the bare rock. I have seen, on the 
 hill of Fyrish, — a lofty eminence of the Lower Old Red 
 which overlooks the upper part of the Cromarty Frith, — a 
 boulder of an exceedingly beautiful, sparkling hornblende, 
 reposing on a stratum of yellow sandstone, fully a thousand 
 feet over the sea, where there is not a particle of the clay 
 in sight. We find these travellers furnishing specimens of 
 almost all the primary rocks of the country, — its gneisses, 
 schistose and granitic, its granites, red, white, and gray, 
 its hornblendic and micaceous schists, and occasionally, 
 though more rarely, its traps. The stone most abundant 
 among them, and which is found occurring in the largest 
 masses, is a well-marked granitic gneiss, in which the 
 quartz is white, and the feldspar of a pink color, and in 
 which the mica, intensely black, exists in oblong accumu- 
 lations, ranged along the line of stratification in inter- 
 rupted layers. No rock of the same kind is to be found 
 in situ nearer than thirty miles. We find granitic boul- 
 ders of vast size abundant in the neighborhood of Tain, 
 especially where the conch-road passes towards the west
 
 A geologist's portfolio. 34b 
 
 through a piece of barren moor, and on the range of sea- 
 beach below. One enormous block, of a form somewhat 
 approaching the cubical, is large enough, and seems solid 
 enough, to admit of being hewn into the pedestal of some 
 colossal statue ; but instead of being thus appropriated to 
 form part of a monument, it has lately been converted of 
 itself into a whole monument. When I last passed the 
 way, I found it dedicated, in an inscription of nine-inch 
 letters, " to the memory of the immortal ScottP Nature 
 had dedicated it to the memory of one of her great revo- 
 lutions ages before; but since the dedicator had detei'- 
 mined on adding, in Highland fashion, a stone to the cairn 
 of Sir Walter, it would certainly have been no easy mat- 
 ter to have added to it a nobler one. 
 
 GRANITIC GNEISS AND SANDSTONE, WITH THE CONDITIONS OF 
 THEIK UPHEAVAL. 
 
 On entering on the granitic rock, we find the strata, 
 strangely disturbed and contorted, lying, in the course of 
 a few yards, in almost every angle, and dipping in almost 
 every direction. And not only must there have been a 
 complexity of character in the disturbing forces, but the 
 rock on which they acted must have been singularly sus- 
 ceptible of being di.sturbed. The strata of the sandstone 
 were, at the period of their upheaval, the same brittle, 
 rigid plates of solid stone that they are now. The strata 
 of the granitic gneiss were characterized, on the contrary, 
 during their earlier periods of disturbance, by a yielding 
 flexibility. They were capable of being bent into ^harp 
 angles without breaking. We see them running in zig- 
 zag lines along the precipices, now striking downwards, 
 now ascending upwards, now curved, like a relaxed Indian 
 bow, in one direction, now curved in a contrary one, like
 
 346 DESCRIPTIVE SKETCHES FROM 
 
 the same bow when fully bent. The strata of the sand- 
 stone, like a pile of glass-panes laid parallel, existed in a 
 state in which they could be either raised in any given 
 angle, or, if the acting forces were violent and partial, 
 broken up and shivered ; whereas the gi'anitic strata ex- 
 isted in the state of the same glass-panes brought to a 
 bright red heat, and capable, from their extreme flexi- 
 bility, of being bent and twisted in any direction. We 
 find, too, that there occur occasional patches in which the 
 lines of the stratification have been together obliterated. 
 We can trace the strata with much distinctness on every 
 side of these ; but there is a gradual obscuration of the 
 lines, and we see what was a granitic gneiss in one square 
 yard of rock existing as a compact homogeneous mass in 
 the next. The eflfect is exactly that which would be pro- 
 duced in the heated panes of ray illustration, were the 
 heat kept up until portions of them began to run ; and 
 the circumstance serves to throAV light on some of the 
 other phenomena of the gneiss. The stone, in its average 
 specimens, is a ternary, consisting of red feldspar, white 
 quartz, and a dingy-colored mica; but no one, notwith- 
 standing, could mistake it for a true granite. It has its 
 granite veins, however; and these veins, truly such in 
 some cases, are, in not a few others, mere strata of the 
 gneiss, which have evidently been formed into granite 
 where they lie. There are no marks of injection, — no 
 accompanying disturbance. All their conditions, with the 
 exception of their being true granites, are exactly those 
 of the layers which repose over and under them. Now, 
 the homogeneous patches serve, as I have said, to throw 
 light on the secret of the formation of these. In one im- 
 portant respect the granitic rocks differ widely among 
 themselves. Some of them contain potass and soda in
 
 A geologist's portfolio. 347 
 
 such large proportions, and have such a tendency to dis- 
 integrate, in consequence, that they furnish much less 
 durable materials for building than the better sandstones ; 
 while others, of an almost indestructible quality, are devoid 
 of these salts altogether. Potass and soda form i^owerful 
 fluxes ; and it seems at least natural to infer that, should 
 wide tracts of granitic rock be exposed to an intense but 
 equable heat, the portions of the mass in which the fluxes 
 exist in large proportions must pass into a much higher 
 state of fluidity than the portions in which they are less 
 abundant, or which are altogether devoid of them. Single 
 strata and detached masses might thus come to be in the 
 state of extremest fusion of which their substance was 
 capable, and all their particles, disengaged, might be enter- 
 ing freely into the combinations peculiar to the plutonic 
 rocks, when all around them continued to bear the semi- 
 chemical, semi-mechanical characteristics of the metamor- 
 phic ones. Hence it is possibly the origin of some of 
 those granite veins, open above, and terminating below in 
 wedge-like points, which have so puzzled the Huttonians 
 of a former age, and which have been so triumphantly 
 referred to by their opponents as evidences that the granite 
 had been precipitated by some aqueous solution. 
 
 SEPTARIA, OR CEMENT-STONES OF THE LIAS. 
 
 Observe these nodular masses of pale, blue limestone, 
 that seem as if they had cracked in some drying pi-ocess, 
 and had afterwards the cracks carefully filled up with a 
 light-colored cement. The flaws are occupied by a rich 
 calcareous spar ; and in the centre of each mass we find, 
 in most instances, a large ill-preserved Ammonite, which 
 has also its spar-filled cracks and fissures, as if it, too, had
 
 34ft DESCRIPTIVE SKETCHES FROM 
 
 been burst asunder by the process wliich had rent the sur- 
 rounding matrix. These nodular masses are the charac- 
 teristic septaria or cementstones of the Lias, so much 
 used in England for making a hard, enduring mortar, that 
 has the quality of setting imder water. Their bluish-col- 
 ored portions are so largely charged with the argillaceous 
 matter of the bed in which they occur, and contain, be- 
 sides, so considerable a mixture of iron, that, refusing to 
 slake like common lime, they have to be crushed, after 
 calcination, by mechanical means ; while the fossil in the 
 centre, and the semi-transparent spar of the cracks, are 
 composed of matter purely calcai*eous. And from this 
 peculiar mixture the cement seems to derive those setting 
 qualities which render it of such value. 
 
 AMMONITES OF THE NORTHERN LIAS. 
 
 The Ammonites of the upper beds of the Lias approach 
 more to the type of the Ammonite commiinis, being com- 
 jDaratively flat Avhen viewed sectionally, and having the 
 whorls broadly visible, as in the Ionic volute ; while the 
 Ammonites of the lower beds approach in type to the Am- 
 monite heterophyllus^ — each succeeding whorl covering so 
 largely the whorl immediately under it, that the spiral line 
 seems restricted to a minute hollow in the centre, scarce 
 equal in extent, in some si^ecimens, to the twentieth part 
 of the entire area. In other words, the Ammonites of the 
 Upper Lias in this deposit represent, as a group, the true 
 ammonite type; while in the Lower Lias they approach 
 more nearly, as a group, to the type of the nautilus. And 
 not only are they massier in form, but also absolutely larger 
 in size. I have found Ammonites in tlie more ponderous, 
 septaria, that fully doubled in bulk any I ever saw in the
 
 A geologist's portfolio. 849 
 
 upper shales. We occasionally find nodules that, having 
 formed in the outer rings of these larger shells, somewhat 
 resemble the rims of wheels, — in some cases, wheels of 
 not very diminutive size. 
 
 BELEMNITES OF THE NORTHERN LL&.S. 
 
 We find the Belemnites of the lower deposit, like its 
 Ammonites, of a bulkier form than those of the upper 
 beds. The Belemnites abbreviatus and elongatiis, both 
 large, massy species, especially the former, are of common 
 occurrence ; while those most abundant in the upper beds 
 are the Belemnites longissimus and penicillatus^ both ex- 
 ceedingly slim species. It is worthy of remark, that Sir 
 R. Murchison, in his list of fossils peculiar to the Lias as 
 developed in the midland counties of England, specifies 
 the Belemjiites ])e7iicillatiis as characteristic of its upper, 
 and the Belemnites abbreviatus and elongatus of its lower 
 division. 
 
 CUTTLE-FISH. 
 
 Is the reader acquainted with at once the largest and 
 most curious of British Mollusca, — the cuttle-fish, — a 
 creature which stands confessedly at the head of the great 
 natural division to which it belongs? Independently of 
 its intrinsic interest to the naturalist, it bears for the com- 
 mentator and the man of letters an interest of an extrinsic 
 and reflected kind. No other mollusc occupies so prom- 
 inent a place in our literature. It is famished with an 
 ink-bag, from which, when pursued by an enemy, it ejects 
 a dingy carbonaceous fluid, that darkens the water for 
 yards around, and then escapes in the cloud, — like some 
 Homeric hero worsted by his antagonist, but favored by 
 
 30
 
 350 DESCRIPTIVE SKETCHES FEOM 
 
 the gods, or some body of military retreating unseen from 
 a lost field, under the cover of a smoking shot. And 
 there has scarce arisen a controversy since the days of 
 Cicero, in which the cuttle-fish, with its ink-bag, has not 
 furnished some one of the controversialists with an illus- 
 tration. It has attained to some celebrity, too, on another 
 and altogether different account. That enormous mon- 
 ster the kraken of Norway, of which our earlier geogra- 
 phers tell such surprising stories, was held to belong to 
 this curious family. And though the monster has disap- 
 peared from the treatises of our naturalists for a full half- 
 century, and from the pages of even our most credulous 
 voyagers for at least a century more, it maintained its 
 place as a real existence long enough to be assigned a pei'- 
 manent niche in our literature. It has been described as 
 raising its vast arms out of the water to the height of tall 
 forest-trees, and as stretching its knobbed and warted 
 bulk, roughened with shells, and darkened with sea-weed, 
 for roods and fui'longs together, — resembling nothing less 
 extensive than some range of rocky skerries on some dan~ 
 gerous coast, or some long chain of sand banks, forming 
 the bar of some great river. It was introduced to the 
 reading world with much circumstantiality of detail, by an 
 old Norwegian bishop (Eric Pontappidon), as "an animal 
 the largest in creation, whose body rises above the surface 
 of the water like a mountain, and its arms like the masts 
 of ships." And one of the French continuators of Bufibn, 
 — Denys Montfort, — regarding it as at least a possible 
 existence, has given, in his history of Mollusca, a print of 
 a colossal cuttle-fish hanging at the gunwale of a ship, 
 and twisting its immense arms about the masts and rig- 
 ging, — a feat which the cuttle-fish of the Indian seas is 
 said sometimes to accomplish, if not with a ship, at least
 
 A geologist's portfolio. 351 
 
 with a canoe. But nowhere does the kraken of Norway 
 look half so imposing or half so poetical as in Milton. In 
 palpable reference to the old bishop's "largest animal in 
 creation," we find the poet describing, in one of his finest 
 similes, — 
 
 " That sea-beast, 
 Leviathan, which God of all his works 
 Created hugicst that swim the ocean stream : 
 Him, haply slumb'ring on the Norway foam, ^ 
 The pilot of some small night-foundered skiff. 
 Deeming some island, oft, as seamen tell. 
 With fixed anchor in his scaly rind 
 Moors by his side under the lee, while night 
 Invests the sea, and wished morn delays." 
 
 The existing cuttle-fish of our seas, though vastly less 
 imposing in its proportions than the kraken of Norway, is, 
 as I have said, a very curious animal, — constituting, as it 
 does, that highest link among Mollusca, in which creatures 
 without a true back-bone or a true brain approach nearest, 
 in completeness of structure and the sagacity of their 
 instincts, to the vertebrata. All my readers on the sea- 
 coast, especially such of them as live near sandy bays, or 
 in the neighborhood of salmon-fishings, must have fre- 
 quently seen the species most abundant in our seas, — the 
 common loligo or strollach {Loligo vulgaris) ; and almost 
 all of them must have the recollection of having regarded 
 it, when they first stumbled upon it in some solitary walk, 
 as an extraordinary monster, worthy of the fii-st place in a 
 museum. "The cuttle-fish," says Kirby, in his Bridgewater 
 Treatise, " is one of the most wonderful works of the Cre- 
 ator." We have no creature at all approaching it in size, 
 that departs so widely from the familiar, every-day type 
 of animal life, whether developed on the land or in the 
 water.
 
 352 DESCRIPTIVE SKETCHES FROM 
 
 A man buried to the neck in a sack, and prepared for 
 such a race as Tennent describes in his " Anster Fair," is 
 an exceedingly strange-looking animal, but not half so 
 strange-looking as a strollach. Let us just try to improve 
 him into one, and give, in this way, some idea of the ani- 
 mal to those unacquainted with it. First, then, the sack 
 must be brought to a point at the bottom, as if the legs 
 were sewed up tightly together, and the corners left pro- 
 jecting so as to form two flabby fins; and further, the sack 
 must be a sack of pink, thickly speckled with red, and tol- 
 erably ojien at the other end, where the neck and head 
 protrude. So much for the changes on the sack ; but the 
 changes on the parts that rise out of the sack must be of 
 a much more extraordinary character. We must first ob- 
 literate the face, and then, fixing on the crown of the head 
 a large beak of black horn, crooked as that of the parrot, 
 we must remove the mouth to the opening betAveen the 
 mandibles. Around the broad base of the beak must we 
 insert a circular ring of brain, as if this part of the animal 
 had no other vocation than to take care of the mouth and 
 its pertinents; and around the circular brain must we 
 plant, as if on the coronal ring of the head, no fewer than 
 ten long arms, each furnished with double rows of concave 
 suckers, that resemble cups arranged on the plane of a nar- 
 row table. The tout ensenxble must serve to remind one 
 of the head of some Indian chief bearing a crown of tall 
 feathers; and directly below the crown, where the cheeks, 
 or rather the ears, had been, we must fix two immense 
 eyes, huge enough to occupy what had been the whole 
 sides of the face. Though the brain of an ordinary-sized 
 loligo be scarcely larger than a ring for the little finger, its 
 eyes are scarcely smaller than those of an ox. To com- 
 plete our cuttle-fish, we must insist, as a condition, that,
 
 A geologist's portfolio, 353 
 
 when in motion, the metamorphosed sack-racer must either 
 walk head downwards on his arras, or glide, like a boy de- 
 scending an inclined plane on ice, feet foremost, with the 
 point of his sack first, and his beak and arms last ; or, in 
 other words, that, reversing eveiy ordinary circumstance 
 of voluntary motion, he must make a snout or cut-water 
 of his feet, and a long trailing tail of his arms and head. 
 The cuttle-fish, when walking, always walks Avith its mouth 
 nearer the earth than any other part of either head or 
 body, and when swimming, always follows its tail, instead 
 of being followed by it. 
 
 This last curious condition, though doubtless, on the 
 whole, the best adapted to the conformation and instincts 
 of the creature, often proves fatal to it, especially in calm 
 weather and quiet inland friths, when not a ripple breaks 
 upon the shore, to warn that the shore is near. An enemy 
 appears ; the creature ejects its cloud of ink, like a sharp- 
 shooter discharging his rifle ere he retreats ; and then, 
 darting away tail foremost under the cover, it grounds 
 itself high upon the beach, and perishes there. Few men 
 have walked much along the shores of a sheltered bay 
 without witnessing a catastrophe of this kind. The last 
 loligo I saw strand itself in this way, was a large and very 
 vigorous animal. The day was extremely calm; I heard 
 a peculiar sound, — a squelch^ if I may employ such a 
 word, — and there^ a few yards away, was a loligo nearly 
 two feet in length, high and dry upon the pebbles. I laid 
 hold of it by the sheath or sack ; and the loligo, in turn, 
 laid hold of the pebbles, just as I have seen a boy, when 
 borne off against his will by a stronger than himself, grasp- 
 ing fast to projecting door-posts and furniture. Tiie peb- 
 bles were hard, smooth, and heavy, but the ci'eature raised 
 them with ease, by twining its flexible arms around them, 
 
 30*
 
 354 DESCRIPTIVE SKETCHES FROM 
 
 and then forming a vacuum in each of its suckers. I sub* 
 jected one of my hands to its grasp, and it seized fast hold; 
 but though the suckers were still employed, it employed 
 them on a different principle. Around the circular rim of 
 each there is a fringe of minute thorns, hooked somewhat 
 like those of the wild rose. In fastening on the hard 
 smooth pebbles, these were overtopped by a fleshy mem- 
 brane, much in the manner that the cushions of a cat's 
 paw overtop its claAvs, when the animal is in a state of 
 tranquillity; and, by means of the projecting membrane, 
 the hollow inside was rendered air-tight, and the vacuum 
 completed ; but in dealing with the hand, a soft substance, 
 the thorns were laid bare, like the claws of the cat when 
 stretched out in anger, and at least a thousand minute 
 prickles were fixed in the skin at once. They failed to 
 penetrate it, for they were short, and individually not 
 strong, but acting together and by hundreds, they took 
 at least a very firm hold. 
 
 What follows the reader may deem bai-barous ; but the 
 men who gulp down at a sitting half a hundred live oys- 
 ters, to gratify their taste, will surely forgive me the de- 
 struction of a single mollusc to gratify my curiosity. I cut 
 open the sack of the creature with a sharp penknife, and 
 laid bare the viscera. What a sight for Hervey when 
 prosecuting, in the earlier stages, his grand discovery of 
 the circulation ! There, in the centre, was the yelloxo mus- 
 cular heart propelling into the transparent tubular arteries 
 the ye^/ow blood. Beat — beat — beat; — I could see the 
 whole as in a glass model; and all I lacked were powers 
 of vision nice enough to enable me to detect the fluid pas- 
 sing through the minuter arterial branches, and then re- 
 turning by the veins to the two other hearts of the crea- 
 ture; for, strange to say, it is furnished with three. There
 
 A GEOLOGIST S PORTFOLIO. o55 
 
 Is the yellow heart at the centre, and, lying altogether de- 
 tached from it, two other darker-colored hearts at the 
 sides ! I cut a little deeper. There was the gizzard-like 
 stomach, filled with fragments of minute mussel and crab- 
 shells ; and there^ inserted in the spongy, conical, yellow- 
 ish-colored liver, and somewhat resembling in form a Flor- 
 ence flask, the ink-bag distended, with its deep dark sepia^ 
 — the identical pigment sold under that name in our color- 
 shops, and so extensively used in landscape-drawing by 
 the limner. I once saw a pool of water, within the cham- 
 ber of a salmon-wear, darkened by this substance almost 
 to the consistence of ink. Where the bottom was laid 
 dry, some fifteen or twenty cuttle-fish lay dead, some of 
 them green, some blue, some yellow ; for it is one of the 
 characteristics of the creature that, in passing into a state 
 of decomposition, it assumes a succession of brilliant col- 
 ors ; but at one of the sides of the chamber, where there 
 was a shallow pool, six or eight individuals, the sole sur- 
 vivors of the shoal, still retained their original pink tint, 
 freckled with red, and went darting about in panic terror 
 within their narrow confines, emitting ink at almost every 
 dart, until the whole j^ool had become a deep solution of 
 sepia. But I digress. 
 
 I next laid open the huge eyes of the stranded cuttle- 
 fish. They were curious organs, — more simple in their 
 structure than those of any quadruped, or even any fish, 
 with which I am acquainted, but well adapted, I doubt 
 hot, for the purpose of seeing. A camera-obscura may be 
 described as consisting of two parts, — a lens in front, and 
 a darkened chamber behind; but in both the brute and 
 human eye we find a third part added ; there is a lens in 
 the middle, a darkened chamber behind, and a lighted 
 chamber, or rather vestibule, in front. Now this lighted
 
 366 DESCRIPTIVE SKETCHES FROM 
 
 vestibule — the cornea — is wanting in the eye of the cut^ 
 tie-fish. The lens is placed in front, and the darkened 
 chamber behind ; the construction of the organ is that of 
 a common camera-obscura, without aught additional. I 
 found something worthy of remark, too, in the peculiar 
 style in which the chamber is darkened. In the higher 
 animals it may be described as a chamber hung with black 
 velvet ; the pigmentum nigrum which covers it is of deep- 
 est black ; but in the cuttle-fish it is a chamber hung 
 with velvet, not of a black, but of a dark purple hue ; the 
 pigmentum nigrum is of a purplish-red color. There is 
 something curious in marking this, as it were, first de- 
 parture from an invariable condition of eyes of the more 
 jDcrfect structure, and in them tracing the peculiarity down- 
 wards through almost every shade of color, to the emerald- 
 like eye-specks of the pecten, and the still more rudimental 
 red eye-specks of the stax'-fish. After examining the eyes, 
 I next laid open, in all its length, from the neck to the 
 point of the sack, the dorsal bone of the creature, — its 
 internal shell, I should rather say, for bone it has none. 
 The form of the shell in this species is that of a feather 
 equally developed in the web on both sides. It gives 
 rigidity to the body, and furnishes the muscles with a ful- 
 crum ; and we find it composed, like all other shells, of a 
 mixture of animal matter and carbonate of lime. In some 
 of the genera it is much more complicated and rigid than 
 in that to which the strollach belongs, consisting, instead 
 of one, of numerous plates, and in form somewhat resem- 
 bling a flat shallop with its cargo rising over the gunwale, 
 or one of the valves of a pearl mussel occujiied by the 
 animal. Is ray description of this curious creature too 
 lengthy ? The young geologist who sets himself to study 
 the fossils of the Oolitic and Cretaceous systems would be
 
 A geologist's portfolio. 357 
 
 all the better for knowing a great deal more regarding it 
 than I have told him here. He will discover that at least 
 one-half the molluscous remains of these deposits, their 
 belemuites, ammonites, nautili, nummulites, baculites, ha- 
 mites, lituites, turrilites, and scaphites, belonged to the 
 great natural class — singularly rich in its extinct orders 
 and genera, though comparatively poor in its existing 
 ones — which we find represented by the cuttle-fish. 
 
 CONGENERS OF THE CUTTLE-FISH, BELEMNITES, ETC. 
 
 Among its many extinct congeners, the order of the 
 Belemnites was one of not the least cm'ious. It has been 
 remarked, that in the cuttle-fish, as we now find it, a 
 greater number of distinct portions of the organization of 
 creatures, belonging to widely-separated divisions of the 
 animal kingdom, are to be seen united than in any other 
 animal. Cut oiF its head immediately below the arms, and 
 we have in the dissevered jDortion, with its ring of nerve, 
 its central mouth, and its suckers, the true analogue of a 
 star-fish. The radiated zoophite lies before us. Some of 
 its genera have their j^lated and jointed antennae placed 
 above and below the eyes. The creature, so far as these 
 organs give it a character, is no longer a zoophite, but an 
 insect or crustacean. But then there is the soft sac, with 
 its fin-like appendages, the internal shell, and the yellow 
 transparent blood. These are unequivocal characteristics 
 of the mollusc. Yes ; but then there is a horny beak, and 
 there a muscular gizzard. It must have laid the bird under 
 contribution for these. There is, besides, a true tongue, 
 and an organ for hearing ; and, though one of tlie cham- 
 bers be awanting, a singularly large and efficient eye. 
 These organs are all borrowed from the vertebrata. And
 
 358 DESCRIPTIVE SKETCHES FROM 
 
 — as if to secure its claim to originality, not only in its 
 combinations, but in its parts — there are its three hearts, 
 and its well-stored ink-bag, — chattels that it could scarce 
 have borrowed anywhere. It occupies, according to Cu- 
 vier, a sort of central place in the animal kingdom, where 
 roads from all the various divisions converge, and the three 
 hearts and the ink-bag mark, as it were, the point at which 
 they meet. Extensive and wonderful, however, as its 
 combination of parts may seem, its extinct congener, the 
 Belemnite, added to the number at least one part more. 
 Like that curious gelatinous zoophite, the Dutch man-of- 
 war {Physalid)^ it was furnished with a sailing apparatus. 
 Not only could it swim tail foremost, and walk head down- 
 wards, like our existing cuttle-fish, but it could also raise 
 itself to the surface of the water, and there, spreading out 
 its sail of thin membrane, speed gaily away before the 
 wind. Several of the existing congeners of the creature, 
 such as the Argonauta ArffO, are sailors still ; but unlike 
 the Belemnite, or its analogue, the cuttle-fish, they ai-e 
 furnished with external shells. They are sailors each in 
 its OAvn little boat, whereas the Belemnite was a sailor 
 without a boat, — such a sailor as Franklin was, when, lay- 
 ing himself at full length in the water, he laid hold of the 
 string of an elevated kite during a smart breeze, and, with- 
 out effort on his own part, was drawn across a small lake 
 by the impulsion of the wind above. 
 
 1 have full in my view where I write, a shelf occupied 
 with ranges of our Scotch Belemnites of the Lias, placed 
 on end, and leaning against the wall, like muskets in an 
 armory. A second shelf exhibits ranges of our Scotch 
 Belemnites of the Oolite. Ere adverting, however, to 
 their specific differences, — differences which their mode of 
 arrangement renders apparent at a glance, — let me select
 
 A geologist's portfolio. 359 
 
 for description an average specimen, as a type of the 
 order. Here, then, is tlie JBelemnite elongatus, from the 
 Upper Lias of Eathie. The architect gives the propor- 
 tions of his cohimns by a scale of diameters. The height 
 of the Tuscan column is equal to seven, that of the Doric 
 to eight, that of the Ionic to nine, and that of the Corin- 
 thian to ten diameters. In describing the proportions of 
 the Belemnite, I shall borrow a hint from the architect, 
 by making my scale one of diameter also ; fixing my 
 calipers, not at the base of the shaft, but one-fourth of its 
 entire length up. Let the reader imagine a small cylin- 
 drical column of brown jjolished stone, diminishing from 
 the base upwards for three-fourths of its height much in 
 the same proportions as one of the Grecian columns 
 diminishes, and then in the remaining fourth suddenly 
 sweeping to a point. Its length — eight inches in the 
 present instance — is equal, like that of a Corinthian 
 shaft, to ten of its diameters. Within this solid column 
 we find an internal cone rising from the common base, the 
 whole of which it occupies, and terminating in the apex, 
 at about one-third the height of the whole. It is dif- 
 ferent in color and structure from the brown pointed 
 shaft at which it is included. The shaft or column shows 
 as if it had been formed, like a dipped candle, by repeated 
 accessions to its outer surface ; whereas the internal cone 
 shows that it has been formed by accessions to its base. 
 The shaft seems to have grown as a tree grows, and ex- 
 hibits its internal concentric rings crossed by lines radi- 
 ating from the centre, just as the yearly rings of the tree 
 are crossed by the medullary rays. The internal cone, on 
 the contrary, was reared course after course, as a pyramid 
 is built of ashlar, — with this difference, however, that it 
 was the terminal course of the apex, that was laid first.
 
 360 DESCRIPTIVE SKETCHES FROM 
 
 and that every siicceeding course was added to the base. 
 The entire Belemnite was originally of greater length than 
 the specimen before us indicates; for the cone extended 
 very considerably beyond the base of the column, and 
 beyond the cone there was a still farther prolongation of a 
 kind of horny sheath, composed of the internal shell of 
 an extinct order of cuttle-fish, its substitute for a verte- 
 brate column; just as the existing loligo has its thin elastic 
 Y>ei\, and the existing sepia its stiffer and more complex 
 bundle of calcareous plates. There are English speci- 
 mens, in which the characteristic ink-bag may still be 
 found resting on the base of the internal cone, giving 
 evidence at once of the class of animals to which the 
 fossil belonged, and that the column and cone must have 
 been internal, not external, shells. Nature, though liberal 
 to all her creatures, is no spendthrift. "VVe find that to 
 her naked Cephalopoda, such as the strollacli and the 
 sepia., she gives in the ink-bag an ability of hiding them- 
 selves in sudden darkness ; but that to the shelled crea- 
 tures of their class, such as the nautilus, she gives no ink- 
 bag. For them the protecting shell is sufficient. The 
 ink-bag of the Belemnite at once shows that it was a 
 cuttle-fish, and that it was naked. Plere, in a specimen 
 from the Whitby Lias, we may see the bag still charged 
 with its ink ; and so slight is the change induced by un- 
 told centuries, in the nature of the carbonaceous substance 
 which composed the latter, that, after having sci'aped it 
 down, and diluted it with water, we may still use it as a 
 pigment. We find it stated by Buckland, that the tinting 
 of a drawing made with fossil ink at his request, by his 
 friend Francis Chantrey, was pronounced by a celebrated 
 painter, unacquainted with the secret of its origin, as pecu- 
 liarly agreeable and well-toned.
 
 A geologist's portfolio. 361 
 
 But the Belemnite, with its horny prolongation, was 
 not merely a sort of stifFener introduced into the body of 
 the creature to give it I'igidity, — as the seamstress intro- 
 duces, for a similar purpose, bits of wire and whalebone 
 into her pieces of dress, or as the pen exists in the strol- 
 lach : the stony column, and its internal cone, constituted, 
 besides, the sailing organs of the creature, — the cone 
 forming its floating apparatus, and the column its ballast. 
 The cone, as I have said, consists of a number of layers, 
 ranged parallel to its base, like courses of ashlar in a i^yra- 
 mid. We find each layer, when detached, exactly resem- 
 bling a thick patent watch-glass, concave on its under, 
 convex on its ixpper, suiihce. Now, each of these formed, 
 in its original state, not a solid mass, but a hollow, thinly 
 partitioned chamber or story ; and, perforating the entire 
 range of stories from apex to base, there was a cylindrical 
 pipe, just as the reader must have seen the cylindrical 
 case of a turnpike stair passing upwards through the 
 stories of some ancient tower from bottom to top. And 
 this pipe was the sii^huncle or pump through which the 
 creature regulated its specific gravity, and sank to the 
 bottom or rose to the surfoce, just as it willed. Mr. J. S. 
 Miller, well known for his labors among the Crinoidea, 
 mentions, in his paper on Belemnites, an interesting ex- 
 periment with regard to the cone. He extracted it care- 
 fully from one of his specimens, and then inserting in the 
 hollow of the stony column which it had occupied, a cone 
 of oiled paper filled with cotton, he placed the specimen 
 in water, and found the buoyancy of the cone compensat- 
 ing so completely for the density of the column, that the 
 whole floated. Xow, to demonstrate the use of the bal- 
 lasting column, let us imagine a sail raised over the cone, 
 and the whole sent to sea in a high Avind. Has the reader 
 
 31
 
 362 DESCRIPTIVE SKETCHES FROM 
 
 ever sailed, when a boy, his mimic ship, and does he 
 remember how imperative it was that there should be lead 
 on the keel ? The stony column is the lead here ; and 
 from the form of the creature, as indicated in the entirer 
 specimens, some such internal ballasting seems to have 
 been as essential to preserve its upright position as the 
 lead is to the boy's ship. There are, however, but few of 
 our naturalists who believe with Mr. J. S. Miller, that the 
 column was originally the dense and solid body it is now. 
 Lamarck held that, like the bone of the existing sejna, it 
 was of " a spongy and cellular texture ; " Parkinson, that 
 it was "porous or cork-like;" and Buckland, that "the 
 idea of its having been heavy, solid, and stony, while it 
 foi-med part of a living and floating sejna, is contrary to 
 all analogy." With an eye to the question, I have suc- 
 ceeded in collecting a number of specimens, which, "svhen 
 in their recent state, had been crushed or broken ; and I 
 am disposed to hold, from the appearance of the fractures 
 in every case, that, notwithstanding the authorities arrayed 
 against him. Miller's view is the right one. The stony 
 column, though it must have been somewhat less bi-ittle 
 in its recent than in its fossil state, — for it contained its 
 numerous thin plates of horn, tenacious, as is natural to 
 the substance, in a considerable degree, — was yet brittle 
 enough to break across at very low angles, and to exhibit 
 on the side to which the force had been applied, its yawn- 
 ing cracks and fissures, though on the opposite side the 
 wrinkled surface generally indicates a tag of adhesion. In 
 the cases, too, in which the Belemnite had been broken 
 into fragments, I have found every detached portion pre- 
 senting its hard, sharp angles, and existing as a brittle 
 calcareous body, however soft and chalky the condition 
 of the more delicate shells of the dej^osit in which it
 
 A geologist's portfolio. 363 
 
 occurred. Nor do I know that analogy is very directly 
 opposed to the supposition that the column might have 
 existed in the creature in its stony state. If two solid 
 calcareous substances, quite as hard and dense as any 
 fossil Belemnite, exist within the head of the recent cod 
 and haddock, why might not one solid calcareous sub- 
 stance have existed within the body of an extinct order 
 of cuttle-fish ? 
 
 I have found considerable difficulty in classing accord- 
 ing to their species, the Belemnites of the Lias. I soon 
 exhausted the species enumerated as peculiar to the for- 
 mation by Miller, and found a great many others. They 
 divide naturally into two well-marked families, — the 
 specimens of a numerous family, that, like the Belemnite 
 elongatus^ are broadest at the base, and diminish as they 
 approach the apex, — while the specimens of a family con- 
 siderably less numerous, like the Beletnnite fusiformis, 
 resemble spear-heads, in being broadest near the middle, 
 and in diminishing toward both ends. In subdividing 
 these great families, various principles of classification 
 have been adopted. There are grooves, single in some 
 species, double, and even triple, in others ; extending 
 from the apex downwards in some — extending from the 
 base upwards in others ; and these have been regarded by 
 Phillips — the geologist who has most thoroughly studied 
 the subject — as constituting valuable characteristics not 
 only of species, but of genera and formations. Miller 
 took into account, as principles of classification, not only 
 the general form, but even the comparative transparency 
 or opacity, of the column, — marks selected in accordance 
 with the belief that the column was originally the solid 
 substance it is now. The order furnishes, doubtless, its 
 various marks of specific arrangement. I have even found
 
 364 DESCRIPTIVE SKETCHES FROM 
 
 the hint borrowed from the architect, of taking the pro. 
 portions of species by their diameters, not without its 
 value. In measuring, for instance, four Avell-preserved 
 specimens of the JBelemnite abbreviatus, one of the bulk- 
 iest which occurs in our Scotcli Lias, and whose average 
 length is six inches, I found that two of the four contained 
 5^ diameters, one 5J diameters, and one 5| diameters ; 
 while another bulky Belemnit'e of the Scotch Oolite, not 
 yet named apparently, whose average length is 3J inches, 
 contains only 3h diameters, and strikes at once as specific- 
 ally different from the others. Equally striking is the 
 specific difference of the Helemnite elongatus, which con- 
 tains from nine to ten diameters, — of another nameless 
 species which contains from twelve to thirteen diameters, 
 — of another which contains from fifteen to sixteen diam- 
 eters, — of another, agreeing in its proportions with the 
 JBelemnite longissimus of Miller, which contains from 
 eighteen to twenty diameters, — of another which con- 
 tains from twenty-three to twenty-four diameters, — and 
 of yet another, long and slender as a heckle-pin, which 
 contains from thirty to thirty-two diameters. My rule of 
 classification must of course be regarded as merely a sub- 
 sidiary one. There are species which it does not distin- 
 guish. It does not distinguish, for instance the Helemnite 
 sulcatus of our Scotch Lias, whose average length is six 
 inches, from the Belemnite elongatus, whose average 
 length is eight. Both agree in containing from nine to 
 ten diameters, though in form and appearance they are 
 strikingly different, — the adjuncatus being much more 
 pointed at the apex than the other, much more finely pol- 
 ished on the surface, and furnished with a deeper groove. 
 As a subsidiary rule, however, I have found the rule of 
 the diameters a useful one. It has enabled me to form a
 
 A geologist's portfolio. 365 
 
 numerous and discordant assemblage of specimens into 
 distinct groups, the specific identity of which, when thus 
 collected, is at once verified by the eye. 
 
 But the reader, unless very thoroughly a geological one, 
 must be of oi^inion that I have said quite enough about 
 the Belemnite. I may, however, venture to add further, 
 that its place in the geological scale is not without its in- 
 terest. The periods of the more ancient formations, from 
 the older Silurian to the older Xew Red Sandstone inclu- 
 sive, had all passed away ere the order was called into ex- 
 istence. It then sjirung into being nearly contemporane- 
 ously with the bird and the reptile ; and, after existing by 
 myriads during the Oolitic and Cretaceous periods, passed 
 into extinction when the ocean of the Chalk had ceased 
 to exist, and just as quadrupeds of the higher order were 
 on the eve of appearing on the stage, but had not yet ap- 
 peared. Since the period in which it lived, though geo- 
 logically modern, the surface of the earth must have wit- 
 nessed many strange revolutions. There have been Bel- 
 emnites dug out of the sides of the Himalaya mountains, 
 seventeen thousand feet above the level of the sea. 
 
 COPEOLITES OF THE LIAS. 
 
 Large coprolites of peculiar appearance, some of them 
 charged with fish-scales of the ganoid order, are tolerably 
 abundant; and they belonged, I have little doubt, to sau- 
 rians. "When bringing home with me, many years since, a 
 well-marked specimen, I overtook by the way an acquaint- 
 ance who had passed a considerable part of his life in 
 Dutch Guiana. The thought did not at first occur to me 
 of submitting to him my specimen. As we walked on to- 
 gether, he thrust his hand into his pocket to bring out his 
 
 3i*
 
 366 DESCRIPTIVE SKETCHES FROM 
 
 handkerchief, and brought out, instead, a large mass of 
 damaged snuff. "Ah," he exclaimed, " that roguish boy ! 
 I was standing with my neighbor, the shopkeeper, this 
 morning, when he was opening up a cask of snuff that 
 had got spoiled Avith sea-water ; and his boy, seeing my 
 pocket provokingly open I suppose, must have dropped in 
 this huge lump ! The joke seems a small one," he contin- 
 ued, "but it miist be at least rather a natural one. The 
 only other trick of the kind ever played me was by a 
 South American Indian, on the banks of the Demerara: 
 he dropped, unseen, into the pocket of my light nankeen 
 jacket a piece of sun-baked alligator's dung." " What 
 sort of a looking substance was it?" I asked, uncovering 
 my specimen, and submitting it to his examination ; " was 
 it at all like that ? " " Not at all unlike," was the reply ; 
 " it bore an exactly similar pale yellow tint, as if, like the 
 dung of our sea-birds that swallow and digest fish-bones, 
 it contained abundance of lime ; and it was sprinkled 
 over, in the same way, with the glittering enamelled scales 
 of that curious fish the bony pike, so common, as you are 
 aware, in our South American rivers." 
 
 JNTEUSrVE DIKES OF EATHIE. 
 
 There are a))pearances in connection with the Lias of 
 Eathie which seem well suited to puzzle the geologist, and 
 which have, in fact, already puzzled geologists not a little. 
 We find them travei'sed by intrusive dykes of what seems 
 a grayish-colored trap, extremely obstinate in yielding to 
 the hammer, and which stand up among the softer shales 
 like the walls of some ruined village. They are trap-dikes 
 in every essential except one; — they occur in every possi- 
 ble angle of disagreement with the line of the strata: in
 
 A geologist's portfolio. 867 
 
 some places they inclose the shale in slim, insulated strips, 
 as a river incloses its islands ; in others they traverse it 
 witli minute veins connected with the larger masses, in the 
 way in which granite is so often seen traversing gneiss ; in 
 yet others the limestone in contact with them seems posi- 
 tively altered; — the blue nodule has, at the line of junc- 
 tion, its strip of crystalline white, and the shale assumes 
 an indurated and veinous character ; the dikes are, in 
 short, trap -dikes in every essential except one; but the 
 wanting essential is of importance enough to constitute 
 the problem in the case; — they are not composed of trap. 
 Some of our mineralogists have been a good deal puzzled 
 by finding crystals of sandstone as regular in their planes 
 and angles as if formed of any of the earths, or salts, or 
 metals, whose law it is to build themselves up into little 
 erections correctly mathematical in every point and line ; 
 and they have read the mystery by supposing that these 
 sandstone crystals are mere casts moulded in the cavities 
 in which crystals had once existed. The puzzle of the 
 Lias dikes is of an exactly similar kind : they are com- 
 posed, not of an igneous rock, but of a hard, calcareous 
 sandstone, undistinguishable in hand-specimens from an 
 indurated sandstone of the Lower Oolite, which may be 
 found on the shore beneath Duui-obin, alternating with 
 shale-beds of the period of the Oxford clay. I succeeded 
 in finding in it, on one occasion, a shell in the same state 
 of keeping in which shells are so often found in the resem- 
 bling rocks of Sutherland, but the species unluckily could 
 not be distinguished. A common microscope at once de- 
 tects the mechanical character of the mass ; and I have 
 learned that Dr. Fleming, after reducing a portion of it, 
 sent him as an igneous rock, to its original sand, simply by
 
 368 DESCRIPTIVE SKETCHES FROM 
 
 submerging it in acid, expressed some little fear lest the 
 sender should not have been quite " up to trap." 
 
 The explanation of the phenomenon seems rather diffi- 
 cult. There are instances in which what had once been 
 trap-dikes are found existing as mere empty fissures ; and 
 other instance»-in which empty fissures have been filled ixp 
 by aqueous deposition from above. An instance of the 
 one kind is adduced, as the reader may perhaps remember, 
 in the "Elements" of Lyell, from M'CulIoch's "Western 
 Islands;" two contiguous dikes traversing sandstone in 
 Skye are found existing to a considerable depth as mere 
 liollow fissures. An instance of the other kind may be 
 found, says M'Cnlloch, in a trap-rock in Mull, which is 
 traversed by a dike that, among its other miscellane- 
 ous contents, incloses the trunk of a tree, converted into 
 brown lignite. In cases of the first kind, the original dike, 
 composed of a substance less suited to resist the action 
 of the Aveather than the containing rock, has mouldered 
 away, and left the vent from which it issued a mere liollow 
 mould, in which the semblance of a dike might be cast, 
 just as the decay and disappearance of the real crystal is 
 supposed to have furnished a mould for the formation of 
 the sandstone one. In cases of the second kind, we see 
 the fictitious dike actually existing ; it is the sandstone 
 crystal moulded and consolidated, and, in short, ready for 
 the museum. And yvc have but to suppose the conditions 
 of the two classes of dikes united, — we have but to sup- 
 pose that the hollow filled by the aqueous deposition had 
 been previously filled by an igneous injection, — in order 
 to account for all the phenomena of an igneous dike ac- 
 companying a merely aqueous one. AVe can scarce account 
 in this way, however, for the formation of the dikes at 
 Eathie, seeing that the shale in Avhieh they are included is
 
 A geologist's portfolio. 369 
 
 of so soft and decapng a character, that no igneous rock 
 could of possibility be more so ; nor, even were the case 
 otherwise, could the upper portion of the dykes have exis- 
 ted as open chasms during the period in which the process 
 of decay would have been taking place in the depths be- 
 low. They would have infallibly filled up with the frag- 
 ments detached from the sides and edges. 
 
 Mr. Strickland, in a paper on the subject in the " Trans- 
 actions of the London Geological Society," states the 
 problem very strongly. "The substance of these dikes is 
 such," he says, " that it is impossible to refer them to a 
 purely igneous origin;" and yet, however much "it may 
 resemble an aqueous product," it is as impossible to doubt 
 that the dikes themselves are genuine "inti'usiA'e dikes 
 penetrating the Lias shale in all directions." He adds 
 further, as his ultimate conclusion in the matter, that the 
 " sedimentary structure of the rock forbids us to refer it to 
 igneous injection from below;" and that, "notwithstand- 
 ing the complete resemblance of these intrusive masses to 
 ordinary plutonic dikes, we have no resource left but to 
 refer them to aqueous deposition, filling up fissures which 
 had been previously formed in the Lias." There is a pecu- 
 liar rock in the neighboi'hood, which throws, I am of opin- 
 ion, very considerable light on their origin. It is what 
 may be termed a syenitic gneiss, abounding in minute 
 crystals of hornblende, that impart to it a greenish hue ; 
 and in one place we find it upheaved so directly among 
 the Lias beds, that it breaks their continuity. It raised 
 them so high on its back, that the denuding agencies laid 
 the back bare by sweeping them away. Let us but imag- 
 ine that this disturbing rock began to rise under the ear- 
 lier imjjulsions of the elevating agencies, and during the 
 deposition of some one of the later secondary formations,
 
 370 DESCRIPTIVE SKETCHES FROM 
 
 as the ijrecursor of the granitic range, — that the super- 
 incumbent Lias, ah'eady existing in its present consolidated 
 state, opened into yawning rents and fissures over it, as 
 the earth opened in Calabria during the great earthquake, 
 - — and that the loose sand and calcareous matter which 
 formed tlie sea-bottom at the time, borne downwards by 
 the rushing water, suddenly filled up these rents, ere the 
 yielding matrix had time to lose any of its steepness of 
 side or sharpness of edge, which it could not have failed 
 to have done had the process been a slow one. The sand- 
 stone dikes, apparently Oolitic, mark, it is probable, the 
 first oj^erations of those upheaving agencies to which we 
 owe the elevation of the granitic wall, and which, ere they 
 accomplished their work, may have been active during oc- 
 casional intervals for a series of ages. I am not of opinion 
 that the accompanying marks of alteration among the 
 shales and limestones of the beds are sufficiently unequiv- 
 ocal to render imperative some more fiery theory. 
 
 C0XTE3IP0RARY AND EXTINCT TYPES OF THE LIFE OF THE 
 TEREBRATULA. 
 
 We find among the earliest bivalves of the Silurian Sys- 
 tem the delicate Terebratula, with its punctured umbone ; 
 we follow it downwards through all the various formations, 
 and see it appearing on each succeding stage, specifically 
 new, but generically old, until, quitting the rocks with 
 their dead remains, we pass to the existing testacea of our 
 seas, and find among them the ancient Terebratula still 
 extant as a living shell. Contemporary as a genus with 
 every extinct form of animal life, we find it contemporary 
 with the last of created beings also, — contemporary with 
 ourselves : and the Terebratula is but one existence of a
 
 A geologist's portfolio. 371 
 
 class to which, though their geneiic antiquity may be 
 rather less remote, nearly the same remark applies. The 
 ostrea still exists, — its congener and contemporary, the 
 gryphgea, has perished; the nautilus survives, — its congener 
 and contemporary, the ammonite, is long since dead ; the 
 cuttle-fish abounds on our shores, — its congener and con- 
 temporary, the belemnite, is to be found in only our rocks. 
 And thus the list runs on. We can scarce glance over a 
 group of fossils, whatever its age, which we do not find 
 divisible into two classes of types, — the types which still 
 remain, aryd the types which have disappeared. But why 
 the one set of forms should have been so repeatedly called 
 into being, and Avhy the other set should have been suf- 
 fered to become obsolete, we cannot so much as surmise. 
 Why, it may be asked, should the nautilus continue to 
 exist, and yet the ammonite have ceased with the ocean 
 that deposited the Chalk? or why should we have cuttle- 
 fish in such abundance, and yet no belemnites? or why 
 should not the gryphaea have been reproduced in every 
 succeeding period with the oyster? In visiting some old 
 family library, that has received no accessions to its cata- 
 logue for perhaps more than a century, one is interested in 
 marking its more vivacious classes of works, — its Specta- 
 tors, and Robinson Crusoes, and Shakspeares, and Pilgrim's 
 Progresses, — in their first, or at least earlier editions, 
 ranged side by side with obsolete, long-forgotten volumes, 
 their contemporaries, that died on their first appearance, 
 and with whose unfamiliar titles one cannot connect a sin- 
 gle association. But it is always easy to say why, in the 
 race of editions, the one class should have been arrested 
 at the very starting post, and why the other should have 
 gone down to be contemporary with every atler produc- 
 tion of authorship, until the cultivation of letters shall
 
 372 DESCRIPTIVE SKETCHES FROM 
 
 have ceased. It is otherwise, hoAvever, with the geologist. 
 He finds he has exactly the same sort of fact to deal with, 
 — an immense multiplication of editions, in the case of 
 some particular type of fish, or plant, or shell, and, in the 
 case of other types, no after instances of re-publication ; but 
 he finds himself wholly unable to lay hold of any critical 
 canon through which to determine why the one class of 
 types should have been so often re-published, or the other 
 so peremptorily suppressed. And yet, were all the circum- 
 stances known, it is possible that some such canon might 
 be found to exist. Geology is still in its infimcy. Shall a 
 day ever arrive when, in a state of full maturity, it will be 
 able to appeal to its fixed canons, and to say why one cer- 
 tain type of existence was fitted for but one definite stage 
 in the progress of things, and some other certain type 
 fitted, by a peculiar catholicity of adaptation, for every 
 succeeding period ? 
 
 SIR DAVID BREWSTER ON THE CUTTLE-FISH AND BELEMNITE. 
 
 The following discovery of Sir David Brewster, regard- 
 ing a marked peculiarity of structure in the eye of the 
 cuttle-fish, now first made public, will be deemed of great 
 interest by all who have learned to admire that inconceiv- 
 able variety of design in the works of the Infinite Mind 
 which grows upon the inquirer the more he examines, and 
 which, if man were not immortal, it would be an error of 
 his very nature to have the strong existing desire to exam- 
 ine : 
 
 St. Leonard's College, St. Andrews. 
 My Dear Sir, — I have been reading, with great pleas- 
 ure, your interesting account of the cuttle-fish, and was 
 glad to find that you had noticed the singular structure of
 
 A geologist's portfolio. 373 
 
 its eye. During the last twenty years I have dissected lit- 
 erally hundreds of cuttle-fish eyes, but I never published 
 my observations on them, in consequence of having found 
 singular discrepancies in the eyes of different species, and 
 having been always expecting from America the eyes of 
 the remarkable varieties which occur there, and which 
 have been repeatedly promised me by American natur- 
 alists. 
 
 As you will take a great interest in the subject, I shall 
 endeavor to give you some idea of what I have done. 
 
 Independent of the peculiarity which you have noticed, 
 of there being no aqueous chamber between the cornea and 
 the lens, there is no iris and no pupil, the quantity of light 
 admitted being regulated by the eyelids. 
 
 The lens itself is of a most singular description. It con- 
 sists of tico lenses sticking together, and capable of being 
 separated without injuring either. This structure is unique. 
 The lens D A E C consists of two, D A 
 E, and a meniscus, m C n, which is kept 
 close to D A C by a double cartilagin- 
 ous ring, D E. The dimensions are D 
 E = 0-51 inch, A C = 0-433 inch, A B 
 = 0-3-133 inch, B C = 0-09 inch; m n 
 = 0-333 inch. The outer diameter of the front ring, D F, 
 is = 0-59 inch, and its inner diameter = 0-31 inch. 
 
 In some indurated lenses I find the lens C to be douhhj 
 convex, and the surface of the lens D E A, on which it 
 rests, concave. This must have been the lens of a differ- 
 ent species. 
 
 The fibrous structure of the lens is very remarkable. 
 The laminae, or coats, of tlie lens are parallel to D A E 
 and m C n; and the fibres of the lens DAE diverge from 
 A as a pole, like the meridians of a globe ; and they all 
 
 32
 
 374 DESCRIPTIVE SKETCHES FROM 
 
 terminate, not in another pole, but in the surface T> E, or 
 that which corresponds with m o n. This termination of 
 the whole component fibres of the lens D A E in a surface 
 is quite unique^ and the mode of converting this rough 
 plane (like a shaving-brush cut across), into a smooth sur- 
 face, is singularly beautiful. Each elementary coat, or 
 lamina, being composed of fibres, has at its termination in 
 the periphery D E a sort of selvage^ where all the fibres 
 end ; and these selvages, being circles, fill up, as it were, 
 or compose the flat surface of the lens. 
 
 The coats, or laminae, consist of fibres difierent from 
 those of all other animals. When other lenses harden, 
 they form a solid body, transparent like a gum ; but the 
 cuttle-fish retains its laminated structure, and shines with 
 all the brilliancy of a pearl. 
 
 In the ScBpia Electona the front lens A 
 separates from B in the line m a b c n^ o. pe- 
 culiarity which I have never found in the 
 Smpia Loligo. The diameter A B is larger 
 
 than m n. 
 
 It would be curious to find the lenses in a 
 fossil state. 
 
 I have found some lenses of the Smpia 
 Loligo of a paraboloidal form. It is probable that the 
 form of the lens varies with the age of the animal. 
 
 When the lenses become indurated, they often exhibit 
 the most beautiful internal reflections, and I have often 
 thought of having them set as brooches. The pearly 
 structure is produced by long exposure under ground ; 
 and it is almost impossible to distinguish such lenses from 
 pearls when the convex part only is shown. — I am, my 
 dear Sir, ever most truly yours, 
 
 D. Brewsteb. 
 
 To Hugh Miller, Esq.
 
 THEORY OF THE OCEAN'S LEVEL, 
 
 AS AFFECTED BY THE RISING OR SINKING OF THE LAND. 
 
 The mean level of the sea cannot be regarded as a fixed 
 line, unless, during the geologic changes of the past, it has 
 invariably maintained the same distance from the earth's 
 centre. If the earth, in consequence of the expansive 
 influence of h vastly higher temperature than that which 
 in the present era it possesses, was once greatly bulkier 
 than it is now, the line, in proportion to the bulk, would 
 be fai'ther removed than it is now from the centre. The 
 sea would stand greatly higher than at its present line. 
 And who that has surveyed the contortions, the bends, the 
 inflections, the ever-recurring rises and falls, of the more 
 ancient stratified rocks, such as our Scotch grauwacke for 
 instance, — bends and inflections that forcibly remind the 
 geologist of the foldings of a loose robe, grown greatly 
 too large for the shrunken body which it covers, — or that 
 has weighed the yet farther evidence furnished by the 
 carboniferous vegetation, extra-tropical in character even 
 in Greenland, — Avho, I say, that has considered this evi- 
 dence will venture to decide that the earth's temperature 
 was not higher, nor the earth's radius greater, in the days 
 of the Silurian period, or of the Coal Measures, than it is 
 now ? And, of course, if the earth's radius was greater,
 
 376 DESCRIPTIVE SKETCHES FROM 
 
 the level line of the sea must have stood higher, — vastly- 
 higher, it seems not impossible, than the line now touched 
 by the summits of our highest mountains. Had there 
 been a graduated pole of adamant, equal in length to the 
 radius of the globe, placed in that ocean of the Silurian 
 period in which our Scotch graptolites lived, — a pole with 
 its lower end fixed immovably at the earth's centre, and 
 its upper end level with the medium surface of the sea, — 
 where, I marvel, would that upper end be now ? High, I 
 suspect in the clouds; nay, in an attenuated atmosphere, 
 to which cloud never now ascends. The graduated mark- 
 ings of the pole, indicatory not merely of how the tide, 
 but also of how the land, has fallen, would, I doubt not, 
 be found more conveniently summable in leagues than in 
 fathoms. 
 
 But even setting aside all this as fanciful and extrava- 
 gant, — even taking it as a given fact (what, I suspect, is 
 no fact at all) that the earth's bulk has not very materially 
 altered, the line of the sea-level may have, notwithstand- 
 ing, been considerably affected simply by the rise of tlie 
 land. It is estimated that aboiit one-fourth part of the sur- 
 face of the globe is occupied, according to the present 
 distribution of oceans and continents, by land, and the 
 remaining three-fourths by Avater ; or, more correctly, that 
 the land is as one, and the water as 2.76. Let us suppose 
 this fourth part of land annihilated to the mean depth of 
 the ocean. Of course, the effect would be, that the ocean, 
 having then to cover four parts, instead of tliree, would 
 sink, all over the globe, exactly one-fourth part of its mean 
 dej)th. If the mean depth of the ocean be, as has been 
 estimated, four miles, the fall in its level that would take 
 2)lace, in consequence of this anniliilation of the land, 
 would be just a single mile. And, of course, a creation
 
 A geologist's portfolio. 377 
 
 of land at the bottom of the sea, which would rise to its 
 surface, would, on the same principle, and in exactly the 
 same ratio, have the effect of elevating the ocean level. It 
 would do on a large scale what the pebbles dropped by 
 the t?row in the fable into the pitcher did on a small one. 
 Nor must it be forgotten, that though creation and anni- 
 hilation are terms which may seem suggestive of the fan- 
 ciful and the extravagant, there are phenomena exceed- 
 ingly common in nature which, for all the purposes of my 
 argument, would have exactly the effect of the things 
 which these terms signify. In intense cold, the mercury 
 in a thermometer is confined to the bulb of the instru- 
 ment; plunged into boiling water, it straightway rises 
 two hundred and twelve degrees in the tube ; and, when 
 a second time subjected to the intense cold, it sinks again 
 into the bulb, as at first. So far as mere bulk is con- 
 cerned, there takes place what is analogous to a creation 
 and annihilation of the quantity of mercury in the tube. 
 Again, if a rod of lead a mile in length be raised in tem- 
 perature from the freezing point to the point at which 
 water boils, it lengthens rather more than five yards; — 
 what is equal to a creation of five yards of lead-i-od has 
 been effected. Cooled down again, however, the five 
 yards are annihilated. A rod of flint-glass of the same 
 length, raised to the same temperature, would stretch out 
 only four feet, two inches, and rather more than seven 
 lines. All the metals — even platinum — expand moi-e 
 than glass ; but were there some deep-lying stratum, five 
 miles in thickness, of that portion of the eailh's crust on 
 which Great Britain rests, to be healed two hundred and 
 twelve degrees above its present temperature, it would at 
 even this comparatively low rate of expansion elevate the 
 island more than twenty feet higher than now over the 
 
 32*
 
 878 DESCRIPTIVE SKETCHES FROM 
 
 existing sea-level, — a height fully equal to that of by far 
 the best marked of our ancient coast lines. And if this 
 increase in temperature took place, not in a stratum of the 
 the earth's crust five miles in thickness, underlying Great 
 Britain, but in a stratum twenty miles in thickness, urttler- 
 lying one-fourth the area of the bed of the ocean, the 
 effect would of course be of a rcA^erse character. This 
 creation of land at the bottom of the sea Avould raise the 
 ocean level nearly twenty feet all over the globe, and send 
 the waves dashing ai'ound our own shores, against the 
 ancient coast line, as of old. 
 
 Nor do I see that the bearing of these consequences on 
 the sea-line — consequences that would render its level 
 dependent on the elevation or submergence of every con- 
 tinent that has existed, or shall yet exist — can be set 
 aside, save on the supposition that for every tract of land 
 that rises, another tract of the same area and cubic con- 
 tents sinks ; or, to state the case in other words, and more 
 definitely, that for every protuberance formed within the 
 sea, there is a corresponding hollow formed also within it 
 elsewhere. Now, even were it to be granted that for 
 every protuberance which rises on the earth's crust there 
 is a corresponding depression of the surface, which takes 
 place somewhere else (though on what j^rinciple this should 
 be granted is not in the least obvious), I do not at all per- 
 ceive why that depression should always take place within 
 the sea. It may take place, not on any of the parts of the 
 earth's surface covered by water, but on that fourth part 
 occupied by land. It may take place on the table-land of 
 a continent. Or, vice versa, a liollow formed in the sea, 
 considerable enough to lower the sea's level, may find its 
 counterbalancing protuberance in the further elevation" of 
 the interior of some vast tract, such as Asia or New Hoi-
 
 A geologist's portfolio. 879 
 
 land, already raised over the ocean. The submerged con- 
 tinent of the Pacific, which now exists but as a wilderness 
 of scattered atolls, may have been the contemporaiy with 
 that of South America, existing at the time as a flat tract, 
 which simply occupied a certain area in the sea ; and the 
 hollow which the submergence of the Polynesian land 
 occasioned may possibly liave been balanced by the rise 
 of those enormous table-lands of Mexico and the adjacent 
 countries that give to the entire continent in which they 
 are included a mean elevation of more than a thousand 
 feet; or the submergence of that Atlantis which was 
 drained by the great rivers of the Wealden period may 
 have been balanced, in like manner, by the rise of the still 
 more extensive table-land of Asia : and in both cases the 
 level of the sea could not fail to be very sensibly lowered. 
 It would have in each instance the area of the submerged 
 continent to occupy ; and there would be no correspond- 
 ing elevation within its bed^ to balance against the waste 
 by the space which it filled. But why, I repeat, the bal- 
 ancing theory at all ? If elevations or depressions can, as 
 has been shown, be mere results of changes of tempera- 
 ture in portions of the earth's crust, why deem it more 
 necessary to hold that there is a refrigerating process tak- 
 ing place under one area, in the exact proportion in which 
 there is a heating process taking place under another, than 
 to hold that when the mercury is rising in the tube of a 
 thermometer, it is sinking in some other tube attached to 
 the instrument, but not visible ? The argument, however, 
 is one of those which can be reasoned out more con- 
 clusively by lines than by words. It Avill be found, too, 
 that the lines make out not only a more conclusive, but 
 also a stronger case.
 
 880 
 
 DESCRIPTIVE SKETCHES FROM 
 
 Fig. II. 
 
 Let the line 3, 3, in the diagram, fig. I., represent that 
 of the sea's mean level ; the line 3 C, or 3 B, the sea's 
 mean depth ; the triangle B A C, a rising continent ; and 
 the internal triangles, whose apices reach the lines 3, 3, 
 and 5, 5, respectively, its comparative bulk or volume dur- 
 ing its various intermediate stages of elevation. When 
 the rising triangle (i. e. continent) reaches the line 3, 3 
 (that of the sea-line ere the land began to rise), its mass, 
 equal to that of the parallelogramic band 1 B C 1, shall 
 have displaced water to that amount, and sent it to the 
 surface, which shall have risen, in consequence, from the 
 line 3, 3, to the line 5, 5. When the continent reaches 
 the line 5, 5, there will be another band, equal to half the 
 mass of the first, displaced and sent to the surface, which 
 shall now have risen to the line 6, 6 ; and not until 
 the point of the triangle (i. e. continent) has reached the 
 line 7, 7, will it have overtaken the rising surface. Such, 
 in proportion to its bulk, would be the effect, on the ocean- 
 level, of a rising continent, were there to be no equivalent 
 sinking of the surface elsewhere, — just as, when tlie mer- 
 cury of the thermometer is rising in the tube, there is no
 
 A geologist's portfolio. 381 
 
 corresponding sinking of metal contained in the instru- 
 ment elsewhere, or, even if there were an equivalent sink- 
 ing, were that sinking to take place iu the interior of some 
 immense tract of table-land. 
 
 Let us now, howevei-, turn to the diagram fig. II,, and 
 consider whether the full realization of the fiction of sink- 
 ing hollows Within the sea, exactly correspondent in their 
 cubic contents to the rising continents, would be at all 
 adequate to preserve the hypothetical fixity of ocean sur- 
 face. Let the line B, C, fig. II. represent the bottom of 
 the ocean, and the triangle B, A, C, a depression of the 
 earth's crust, exactly equal in cubic amount to the rising 
 land in fig. I., and taking place exactly at the same time. 
 It will be at once seen, in running over the details, that 
 even the hypothesis of balancing hollows formed in the 
 sea as a set-oflf against the elevations, is wholly insufiicient 
 to establish the theory of a fixed line of sea-level. The 
 hollow might be formed, and yet the level aflTected not- 
 withstanding. Until the elevation had risen above the 
 line 3, 3, in the diagram fig. I., and the corresponding 
 hollow sunk to the line 3, 3, in the diagram fig. II., the 
 surface-line would remain unaff*ected, — the water displaced 
 by the rising eminence would be contained in the sinking 
 hollow ; but immediately as the land rose over the surface, 
 there would be a portion of it — the sub-aerial portion — 
 which would displace no water. The hollow, if it took 
 place in the exact ratio of the elevation, — and such is the 
 stipulated condition of the theory, — would receive, after 
 this point, exactly double the quantity of water that the 
 land displaced, and the line of the sea-level would fall. 
 When the elevation would have risen to the point A of 
 the one diagram, and the hollowing depression sunk to the 
 point A of the other, the amount of water received over 
 water displaced would be equal in quantity to one of the
 
 38ir DESCRIPTIVE SKETCHES FROM 
 
 parallelogramic bands, 1 2, 2 1, or 2 3, 3 2, fig. I.; and the 
 sea-level would in consequence sink to the line 2, 2, The 
 exactly balanced hollow would fail to iDreserve the balance. 
 And so I cannot continue to hold as a first principle, 
 that the line of the sea-level is a fixed and stable line ; 
 seeing that ere I could do so I would have to believe, ^rs^, 
 that the earth's radius has undergone no diminution since 
 the earliest geologic periods in which an ocean existed ; 
 second^ that for every elevation which takes place on the 
 surface of the globe there takes place a corresponding 
 depression upon it elsewhere ; third, that if the elevation 
 takes i^lace within the bed of the sea, the depression also 
 takes place within the bed of the sea ; and, fourth, that 
 the elevations and depressions bear always a nicely-adjusted 
 l^roportion to each other in their contents, — diflerent at 
 two different stages of their formation, — being up to a 
 certain jioint exactly as one to one ; and after that point 
 has been reached, exactly as one to two. And I can find 
 no adequate grounds for believing all this. But though it 
 be thus far from self-evident that the mean level of the 
 ocean\s a fixed line, its rises and falls must have been 
 slight indeed compared with those of the land. There 
 are some of the Alps more than fifteen thousand feet in 
 height ; but, if spread equally over Europe, they would 
 raise the general surface, says Humboldt, little more than 
 twenty-one feet. And the displaced masses of the ocean, 
 whether occasioned by the rising or the sinking of conti- 
 nents, have always to be spread over a surface thi-ice 
 greater than that of all the land. A displacement, how- 
 ever, effected by the sinking of a continent which bore as 
 large a propoi'tion to the ocean as that borne by the Alps 
 to Europe, would lower the general sea-line from the 
 mean level of by fnr the best-marked of our ancient coast 
 lines to the mean level of the existins: one.
 
 THE CHAIN OF CAUSES. 
 
 '' It is no recent discovery," says an ingenious French 
 writer of the last century, " that there is no eiFect without 
 a cause, and that often the smallest causes produce the 
 greatest effects. Examine the situations of every people 
 upon earth ; — they are founded on a train of occurrences 
 seemingly without connection, but all connected. In this 
 immense machine all is wheel, pully, cord, or spring. It is 
 the same in physical nature. A wind blowing from the 
 southern seas and the remotest parts of Africa brings with 
 it a jDortion of the African atmosphere, which, falling in 
 showers in the valleys of the Alps, fertilizes our lands. 
 On the other hand, our north wind carries our vapors 
 among the negroes : we do good to Guinea, and Guinea 
 to us. The chain extends from one end of the universe 
 to the other." Waiving, however, for the pi-esent, the 
 moral view of the question, I may be permitted to present 
 my readers with an illustration of the physical one, — i. e. 
 the dependence of the conditions of one country on the 
 conditions on which some other and mayhap very distant 
 country exists, — which may be new to some of them, and 
 which the Frenchman just quoted could have little antici- 
 pated. 
 
 When in the island of Bute, to which I had gone on 
 two several occasions in the course of a few weeks, in
 
 384 DESCRIPTIVE SKETCHES FROM 
 
 order to examine what arc known to geologists as the 
 Pleistocene deposits of the Kyles, ray attention was di- 
 rected to a deep excavation which had just been o2)ened 
 for the construction of a gas tank in the middle of the 
 town of Rothesay. It was rather more than twenty feet 
 in depth, and passed through five different layers of soil. 
 First, passing downwards, there occurred about eighteen 
 inches of vegetable mould, and then about seven feet of a 
 partially consolidated ferruginous gravel, which rested on 
 about eighteen inches more of peat moss, — once evidently 
 a surface soil, like the overlying one, though of a different 
 character, — abounding in what seemed to be the frag- 
 ments of a rank underwood, and containing many hazel- 
 nuts. Beneath this second soil there lay fully nine feet of 
 finely stratified sea-sand ; and under all, a bed of arena- 
 ceous clay, which the workmen penetrated to the depth 
 of about two feet, but, as they had attained to the required 
 depth of their excavation, did not pasi through. And this 
 bed of clay, at the depth of fully t^vonty feet from the 
 surface, abounded in sea-shells, — iic'c existing in the petri- 
 fied condition, but, save that they had become somewhat 
 porous and absorbent, in their original state. Not a few 
 of them retained the thin brown epidermis, unchanged in 
 color ; and the gaping and boring shells, whose nature it 
 is to burrow in clay and sand, and which Avere present 
 among them in two Avell-marked species, occupied, as 
 shown by their position, the place in which they had 
 lived and died. Now, of these ancient deep-lying shells, 
 though a certain portion of them could be recognized as 
 still British, there were proportionally not a few that no 
 longer live within the British area; — in vain might the 
 conchologist cast dredge for them in any sea that girdles 
 the three kingdoms ; and the whole, regarded as a group.
 
 A geologist's portfolio. 385 
 
 differ from any other that exists in Europe in the present 
 day. Ere, however, I pass on to decipher the record 
 which they form, or translate into words the strange old 
 pre-historic facts with which they are charged, let me 
 briefly refer to the overlying deposits, and the successive 
 periods of time which they seem to represent. 
 
 The upper layer of vegetable mould here fully exhausts 
 the historic period. And yet the fine old tOAvn of Rothe- 
 say is not without its history. The ancient ivy-clad castle 
 of the place is situated scarce a minute's walk from the 
 excavation ; the same stratum of vegetable mould lies 
 around that forms the upper layer in the pit, furnishing 
 rich footing to shrub and tree ; and its great moat, de- 
 serted long since by the waters, was excavated of old in 
 the ferruginous gravel. And yet, though compared w^ith 
 the age of the gravel-bed on which it stands, the date of 
 its erection is as of yesterday: history fails to trace its 
 origin ; we only know that it "was already an important 
 stronghold in the days of Haco of Norway, one of whose 
 captains besieged and took it, — that Robert III. of Scot- 
 land died broken-hearted within its walls, — and that it 
 still furnishes with his second title the heir-apparent of the 
 British throne. On many other parts of the coast, though 
 apparently not here, this gravel-bed contains shells, all of 
 which, unlike those of the arenaceous clay beneath, still 
 live around our shores, and most of which occuri-ed, ere the 
 last upheaval of the land, as dead shells on the beaches of 
 the old coast line. The old line itself, against which the 
 sea seems to have stood for ages ere the final upheaval, is 
 present here immediately behind the town, in an emi- 
 nently characteristic form. Its precipices of rough con- 
 glomei-ate still exhibit the hollow lines, worn of old by 
 \he surf, and occupy such places in relation to the build- 
 
 33
 
 386 DESCRIPTIVE SKETCHES FROM 
 
 ings below as prove that even the oldest erections of the 
 town, Avith the first beginnings of the castle, were all raised 
 on one of its wave-deserted beaches. But the annals of 
 Rothesay, notwithstanding their respectable antiquity, or 
 even such memorials of human origin in the neighborhood 
 as altogether extend beyond the memory of history, ad- 
 vance but comparatively a little way towards the period 
 of the old coast line and the last upheaval. When, in the 
 times of Julius Caesar, Diodorus Siculus wrote his big gos- 
 sipping history, St. Michael's Mount, in Cornwall, was con- 
 nected with the mainland at low water as it is now, — a 
 fact good in evidence to show that since that age the 
 respective levels of land and water have not altered in. 
 Britain. The old coast line must have been already 
 upheaved when Cassar landed in the island. And yet, 
 though, as shown by its profound caves and deeply ex- 
 cavatfeti hollows, the sea must have beaten against it dur- 
 ing an immensely protracted period of depression, there 
 existed a previous period of upheaval, represented by the 
 layer of moss at the bottom of the gravel, when the land 
 must have stood considerably higher over the sea-level 
 than it does now. In many localities around the shores 
 of Britain and Ireland, the moss-bed which so often under- 
 lies the bed of old coast gravel is found to run out under 
 the sea to depths never laid bare by the tide ; and yet, at 
 least as low as the sea ever falls, it is found bearing its 
 stumps and roots of bushes and trees of existing species, 
 that evidently occupy the place in which they had origi- 
 nally grown and decayed. These submerged mosses, as 
 they are termed, occur along the sides of the Friths of 
 Tay and Forth, and in at least one locality on the southern 
 side of Moray Frith ; on the west coast they lie deep in 
 lochs and bays ; they occur on various parts of the coasts
 
 A geologist's portfolio. 387 
 
 of Ireland ; and off tlic shores of Erris and Tyrawly have 
 furnished a basis for strange legends regarding an en- 
 chanted land, which once in every seven years raises its 
 head above the water, green with forests and fields, but 
 on which scarce any one has succeeded in landing. They 
 occur also on the English shores, in one interesting in- 
 stance in the immediate neighborhood of that St. Michael's 
 Mount which, from the description of the Sicilian historian, 
 furnishes a sort of negative measure of the period during 
 which the gravel bed immediately over them was elevated. 
 "On the strand of Mount's Bay, midway between the piers 
 of St. Michael's Mount and Penzance, on the 10th of Jan- 
 uary, 1757," says Borlase, in his "Natural History of Corn- 
 wall," " the remains of a wood, which anciently must have 
 covered a large tract of ground, appeared. The sands had 
 been drawn off from the shore by a violent sea, and had 
 left several places, twenty yards long and ten w^ide, washed 
 bare, strewed with stones like a broken causeway, and 
 wrought into hollows somewhat below the rest of the 
 sands. This gave me an opportunity of examining the 
 following parts of the ancient trees: — In the first pool 
 part of the trunk appeared, and the roots in their whole 
 course, eighteen feet long and twelve wide, were displayed 
 in a horizontal position. The trunk at the fracture was 
 ragged ; and beside the level range of the roots which lay- 
 round it was part of the body of the tree, just above 
 where the roots divided. Of what kind it was there did 
 not remain enough positively to determine. The roots 
 were pierced plentifully by the teredo or auger worm. 
 Thirty feet to the west we found the remains of another 
 tree : the ramifications extended ten feet by six ; there 
 was no stock in the middle ; it was therefore part of the 
 under or bottom roots of the tree, pierced also by the
 
 888 DESCRIPTIVE SKETCHES FROM 
 
 teredo, and of the same texture as the first. Fifty feet to 
 the north of the first tree we found part of a large oak: it 
 was the body of a tree three feet in diameter ; its top in- 
 clined to the east. We traced the body of this tree, as it 
 lay shelving, the length of seven feet ; but to what further 
 depth the body reached we could not discern, because of 
 the immediate influx of water as soon as we had made a 
 pit for discovery. It was firmly rooted in earth six inches 
 from the surface of the sand. Not so fixed was the stock 
 of a willow tree, Avith the bark on, one foot and a half in 
 diameter, within two paces of the oak. The timber was 
 changed into a ruddy color; and hard by we found pai't 
 of a hazel-branch, with its glossy bark on. The earth in 
 all the tried places appeared to be a black, cold marsh, 
 filled with fragments of leaves of the Juncus aquaticus 
 maximus. The place where I found the trees was three 
 hundred yards below full sea-mark. The water is twelve 
 feet deep upon them when the tide is in." It will be seen 
 from this description, — and it agrees M'ith that of our 
 submerged forests of the period generally, — that the trees 
 which grew on this nether soil, when the level of the land 
 stood considerably higher than it docs now, were exactly 
 those of our present climate, — a fact borne specially out 
 by the numerous hazel-nuts Avhich the deposit almost 
 everywhere contains. The hazel is one of the more deli- 
 cate indigenous trees of the country. It was long ago 
 remarked in Scotland by intelligent farmers of the old 
 school, that "a good oint year was always a good oat year;" 
 and that "as the nut filled the oat filled." And now our 
 philosophical botanists confirm the truthfulness of the ob- 
 servation embodied in these proverbial sayings, by select- 
 ing the hazel as the indigenous plant which most nearly 
 resembles in its constitution the hardier cereals. It rises
 
 A geologist's portfolio. 389 
 
 on our hill-sides to the height, but no higher, to which 
 cultivation extends ; and Avhere the hazel would fail to 
 grow, checked by the severity of the climate, it would be 
 in vain to attempt rearing the oat, or to expect any very 
 considerable return from either rye or barley. The exis- 
 tence of hazel-nuts, then, in this mossy stratum, is fraught 
 with exactly the same sort of evidence regarding the cli- 
 mate of that period of upheaval which it represents, as 
 that borne by the shells of the overlying gravel to the 
 subsequent period when the sea stood against the old 
 coast line. Equally during both periods our country pos- 
 sessed its present comparatively genial climate, — the finest 
 enjoyed by any country in the world situated under the 
 same latitudinal lines. But the bed beneath gives evi- 
 dence of an entirely different state of things. 
 
 Under the stratum of moss, as we have already said, 
 there oc^ui'S in the Rothesay pit a thick bed of stratified 
 sea-sand, and under the sand a bed of clay charged with 
 shells ; and these shells exist no longer as a group in the 
 British seas. Regarded as characters charged with the 
 climatal history of the period that represents the stratum 
 in which they occur, the following list, with the attached 
 explanations, may be regarded as indicative of the mean- 
 ings which they bear. We may mention, that the greater 
 number of the specimens specified were collected in the 
 pit after our first visit to it, by Mr. John Richmond of the 
 Temperance Hotel, Rothesay, to whose intelligent guidance 
 and direction the geologic traveller, desirous of cultivating 
 an adequate acquaintance with the Pleistocene deposits of 
 the island in the least possible time, would do well to com- 
 mit himself. 
 
 33*
 
 390 
 
 DESCRIPTIVE SKETCHES FROM 
 
 Natica clausa, 
 
 Trophon scalariforme, 
 Buccinum Humphreysianum, 
 
 Trochus inflaius, 
 
 Undescribed natica, 
 Trophon dathratus, 
 Litlorina rudis, 
 TelUna proxima, 
 
 Saxicava sulcata, 
 Mya UddevaUensis, 
 
 Undescribed modiola, 
 
 Mya truncata, 
 Saxicava rugosa, 
 Lucina flexuosa, 
 Astarte compressa, 
 Nucula Nucleus, 
 
 Not now a British species, but found living 
 in tlic North Sea as far as Spitzbcrgen, 
 and on the shores of boi'eal America. 
 
 Not now British, but hving in the samo 
 boreal seas as the other. 
 
 One of the rarest of British shells. "It 
 appears," say Messrs. Forbes & Hanley 
 in their history of the British Mollusca, 
 "to be an arctic form lingering in our 
 fauna." 
 
 Not now British; existing habitat unascer- 
 tained. 
 
 Ditto : ditto. 
 
 British; but also boreal. 
 
 Ditto : ditto. 
 
 Not yet found living in the British area, 
 but abundant on the coasts of Greenland, 
 boreal America, etc. 
 
 Not now British. 
 
 Now deemed a variety of Myatruncata, but, 
 save that it was found in one instance by 
 Dr. Fleming among the Shetland Islands, 
 not a British, but a boreal variety. 
 
 Not now British : existing habitat unascer- 
 tained. 
 
 British ; but also boreal. 
 
 Such were the shells found in the arenaceous clay-bed 
 of the Rothesay pit, full twenty feet from the surface; and 
 from where, in various other parts of the country, the 
 same bed has been reached by excavations, or found crop- 
 ping out along the shores, the list has been greatly in- 
 creased. At Balnakaille Bay, for instance, in the Kyles 
 of Bute, where Mr. Smith of Jordnnhill, — one of our 
 highest authorities on the Pleistocene formation, — first de-
 
 A geologist's portfolio. 391 
 
 tected the deposit, we found several specimens of the Pec- 
 ten Islandicus, — a fine shell, which, though abundant on 
 the coast of Labrador, has not been found living on those 
 of Britain ; with specimens of Panopea Norwegica., — a 
 massive shell, of the same boreal character, recently, how- 
 ever, found on our coast ; though such its extreme rarity, 
 that a conchological friend tells us he was lately offered a 
 British specimen for sale, at the not very moderate price 
 of two pounds ten shillings. Even in the instance in 
 which the shells are not only British, but also not of ex- 
 treme rarity, the proportions in which they occur in the 
 beds are certainly exotic. Astarte elliptica, for instance, 
 is by no means a common Astarte in the Scottish seas, nor 
 is it all known in those of England or Ireland ; whereas 
 in Greenland it is very abundant ; and in those beds in 
 which it is the prevailing Astarte, it is in the Greenlandic, 
 not in the Scottish proportions, in which it occurs. In 
 the same way Ci/prina IslancUca, though comparatively 
 rare in the Frith of Clyde, is not rare in the Scottish seas 
 generally ; but it is in the seas of Iceland, as its name im- 
 plies, that it attains to its fullest numerical development ; 
 and in the Pleistocene beds of the Clyde it is in the Ice- 
 landic, not the Scottish proportions, that we find it. The 
 same remark applies to Cardinra Norxoegica and Astarte 
 compressa., with not a few others ; and still more strongly 
 to another Astarte, not rare in the Pleistocene deposits of 
 at least Banffshire and Caithness, but so exceedingly rare 
 as Scottish in the present age of the world, that the late 
 Professor Edward Forbes, — indefatigable dredger as he 
 was, — had to borrow from a friend the Scottish specimen 
 which he figures in his great work. But though of such 
 unfrequent occurrence in the Scottish seas, it is common 
 in those of Nova Zembla and within the Arctic circle;
 
 392 DESCRIPTIVE SKETCHES FROM 
 
 and it is in the proportions in which it is developed in the 
 high latitudes that we now find it in the Pleistocene beds 
 of Scotland, 
 
 But how interpret so curious a fact as the occurrence in 
 this country of beds of shells (evidently occupying the 
 place in which they had lived and died) whose proper cli- 
 matal habitat is now some ten or fifteen degrees farther to 
 the north ? There is nothing more fixed than the nature 
 of species. Art, within certain limits exerts an acclimatiz- 
 ing power; Alpine plants may be found, for instance, liv- 
 ing, if not flourishing, within the Botanic Gardens of 
 Edinburgh, elevated scarce a hundred feet above the level 
 of the sea ; but every scientific gardener knows how ex- 
 tremely difficult it is to keep those alive in the too genial 
 temperature of situation greatly lower than the one natu- 
 ral to them ; and that while intertropical plants may be 
 easily maintained in existence through the judicious appli- 
 cation of artificial heat, the sub-arctic or Alpine plants are 
 ever and anon dying out. And never do they so change 
 their natui-es as of themselves to propagate their kind down- 
 wards from the hill-tops to the plains. They on no occa- 
 sion violate the climatal conditions imposed upon them by 
 nature. It is so also with the animal world, and especially 
 with shells. There are shells reckoned British, so deli- 
 cately sensible of cold, that their northern limit barely 
 touches the southern shores of Britain. That fine bivalve 
 Cytherea chione is one of these, never getting farther north 
 than Caernavon Bay ; Cardiwn rusticum, so graphically 
 described by Mr. Kingsley in his " Glaucus," under the 
 style and title of Signor Tuberculato, is another, rang- 
 ing southward to the Canaries, but barely impinging, in 
 its northern limits, on the shores of Devon and Cornwall ; 
 and our splendid Haliotus, or ear-shell, JT. tubercidata.
 
 A geologist's portfolio. 'S^'3 
 
 though reckoned British by courtesy, does not even touch 
 the British shores, but finds its northern limit at the Chan- 
 nel Islands. Nor are the northern shells more tolerant of 
 warm than the southern ones of cold water. We have 
 already referred to Astarte elliptica as finding its southern 
 line of boundary on the Scottish coasts; Pecten Niveus 
 has not occurred to the south of the Frith of Clyde ; and 
 TrocJms icndulatus, though it ranges to Greenland, barely 
 reaches our northern and western shores. Such and so 
 nice is the dependence of shells on conditions of tempera- 
 ture, and such and so nice is their restriction to climatal 
 areas. Nor could they have had a diflferent nature in the 
 past. How, then could the cold JVcttica clausa and Tro- 
 l)hon scalariforme of Spitzbergen and boreal America, and 
 the Telliiia proxima and Mya Uddevallensis of Greenland 
 and the North Cape, have been at one time living deni- 
 zens of the bay of Rothesay? Under what sti'ange cir- 
 cumstances could whole scalps of the Pecten Islandicus 
 have thriven in the Kyles of Bute, accompanied by groups 
 of boreal Saxicava, that dug themselves houses in the 
 stiff clay, and massive Panopea, that burrowed in the 
 mud ? The island of Bute is famous for now possessing 
 perhaps the finest climate in Scotland; exotics blow in its 
 gardens and shrubbei-ies, that demand elsewhere the shel- 
 ter of a greenhouse ; and yet there was a time when, 
 judging from the extreme boreal character of its shells, it 
 pined under a severe and ungenial climate, in which CA'en 
 the hardier cereals could not have ripened. How accoitnt 
 for a state of things so very unlike the present? 
 
 Questions in natural science cannot be resolved with all 
 the certainty of questions in astronomical or mathematical 
 science. Adams and Le Verrier could not only infer from 
 the disturbances of Uranus the existence of a hitherto un-
 
 394 DESCRIPTIVE SKETCHES FROM 
 
 known planet, but even indicate its place in the heavens. 
 But though the varying climatal circumstances of our 
 country, and of northern Europe generally, seem to have 
 depended scarce less surely on the varying physical condi- 
 tions of another country three thousand miles away, than 
 the irregularities of the planet Uranus did upon the mass 
 and position of the planet Nej^tune, we question whether 
 any amount of skill, or intimacy of acquaintance with the 
 phenomena, could have led to an a priori anticipation of 
 the fact. We shall afterwards show, however, that the cli- 
 mate of northern Europe is mainly dependent on the condi- 
 tions of northern America; and that one certain change in 
 its condition gave to our country the severe climate which 
 obtained when Natica claxisa and Tellina lyroxinia lived 
 in the bay of Pvothesay; and that it is a result of another 
 certain change in its condition, that the delicate fuschia 
 now expands its purple bells in Bute on the soil by which 
 great deep-lying accumulations of these sub-arctic shells 
 are covered. 
 
 Let us first remark, that during the period of the boreal 
 shells the land was greatly depressed. The subsequent de- 
 pression — that represented in the Rothesay excavation by 
 the upper gravel-bed, — that which succeeded the age of 
 the submerged mosses, — that during which the waves 
 broke against the old coast line, — seems to have been 
 restricted to a descent of some thirty, or at most forty, feet 
 beneath the level which the land at present maintains; 
 whereas the previous depression — that represented by the 
 bed of arenaceous clay and the boreal shells — niust have 
 been a depression of many hundred feet. No such infer- 
 ence, however, could be based on any of the Bute deposits 
 which we have yet seen ; and yet we might safely con- 
 clude, even from them, that when the deep-sea shells lived
 
 A geologist's portfolio. 395 
 
 where we now find them, the land must have sat compar- 
 atively low in the water. When scalps of Pecten Islcmd- 
 icus throve on the argillaceous bed cut open above tide- 
 mark by the little stream which falls into Balnakaillie Bay, 
 and noble Panopea burrowed in its stiff clay, Bute must 
 have existed, not as one, but as three islands, separated 
 from each other by ocean sounds occupying the three val- 
 leys by which it is still traversed from side to side. In the 
 neighboring mainland many a promontory and peninsula 
 must have also existed as detached islands. The long 
 promontory of Cantyre and Knapdale, traversed by open 
 sounds at Tarbert and Crinan, must have formed two of 
 these ; the larger part of the shire of Dumbarton, cut off 
 from the main land by straits passing inwards through the 
 valleys of the Leven and of Loch Long, must also have 
 borne an insular character; Loch Lomond must have ex- 
 isted, not as a fresh-water lake, but as an interior sea; 
 and, in fine, the whole geography of the British islands 
 must have been widely different from what it is now. 
 There are other localities, however, in which, from the ele- 
 vation of the boreal shell-bed over the present sea-level, 
 we are justified in inferring that the depression of the land 
 must have been much greater than that indicated by the 
 beds of Bute. The same bed, and containing the same 
 shells, was laid open in forming the Glasgow and Greenock 
 Railway, a little to the west of Port Glasgow, at an eleva- 
 tion of about fifty feet over the high-water line. It was 
 detected at Airdrie, about fifteen miles inland, in the first 
 instance, at a height of three hundred and fifty feet over 
 the sea, and subsequently at the still more considerable 
 height of five hundred and twenty-four feet. We our- 
 selves have disinterred the same shells from where they 
 rested, evidently in situ, in Banffshire, — on the top, in
 
 896 DESCRIPTIVE SKETCHES FROM 
 
 one instance, of a, giddy cliiF, elevated two hundred and 
 thirty feet over the beacli, — in another, lying deep in the 
 side of a valley once a long withdrawing frith, but now 
 fully six miles from the sea, and raised about a hundred 
 and fifty feet above it. In Caithness they have been de- 
 tected by Mr. Robert Dick at the greatest heights to which 
 the boulder-clay attains ; they occur also at very consider- 
 able heights in the boulder-clay of the Isle of Man ; and 
 were found by Mr. Trimmer in the drift of Moel Tryfon, 
 in North AYales, at the extraordinary elevation over the 
 sea of fifteen hundred feet. When the boreal shells at 
 Airdrie lived, Scotland must have existed as a wintry archi- 
 pelago, separated into three groups by the oceanic sounds 
 of the great Caledonian Valley, and of the low flat valley, 
 now traversed by the Union Canal, which extends between 
 the Friths of Forth and Clyde. And when the shells of 
 Moel Tryfon lived, only the higher parts of the Highlands 
 of Scotland, and of the Cheviot and Lammermoor groups, 
 could have had their heads elevated over the wintry ice- 
 laden seas of the Pleistocene ages. There are grounds for 
 holding that the period, though one geologically, was of 
 vast extent, — that the degree of submergence was greater 
 at one time and less at another ; or, more strictly speaking, 
 that the commencement of the period was one of grad- 
 ual depression in the British area, — that about its mid- 
 dle term all was submerged, save the hill-tops and higher 
 table-lands, — and that our country then began gradually 
 to rise, until, about the close of the wintry eon, its level 
 was mayhap scarce a hundred feet lower than it is at 
 present. But though compai-atively greater and less at 
 different times, there seems to have been no time during 
 the period, iu which the depression was not absolutely 
 gi-eat.
 
 A geologist's portfolio. 397 
 
 Let us next remark, as very important to our argument, 
 that not only was the period one of depression in the Brit- 
 ish area, but also very extensively in the northern hemi- 
 sphere generally. The shell-beds of Uddevalla — identi- 
 cal in the character and species of their organisms with 
 those of the Clyde — are elevated two hundred feet above 
 the neighboring Cattegat; and in Russia Sir Roderick 
 Murchison detected similar beds in the valley of the Dwina, 
 lying nearly two hundred miles south-east of Archangel, 
 and at least a hundred and fifty feet over the level of the 
 White Sea. It is not uninteresting to mark, in the list of 
 shells given by Sir Roderick in his great work on Russia, 
 and which were the product, he states, of not more than 
 two hours' exploration among these fir inland beds, exactly 
 the names of the same species that occurred in the Rothe- 
 say excavation, or may be found in the Pleistocene depos- 
 its of the Kyles. We recognize as the prevailing forms, 
 Natica clausa, Pecten Islajidicus, Astarte elliptica^ As- 
 tarte compressa, Mya truncata in both its boreal and more 
 ordinary varieties, and Tellina proxinxa., with many others. 
 The inscriptions borne by the Pleistocene of both Sweden 
 and Russia are formed of the same character as those ex- 
 hibited by the Pleistocene of our own country, and tell 
 exactly the same story. But it is of still more importance 
 to our argument, that the Pleistocene of America is also 
 inscribed with similar characters, and is coupled with sim- 
 ilar evidence. Shell-beds identical in their contents with 
 those of the Clyde, Uddevalla, and the valley of the 
 Dwina, have been detected in the neighborhood of Que- 
 bec, at the height of two hundred feet over the Atlantic, 
 and traced onwards by Mr. Logan, the accomplished state- 
 geologist for the Canadas, to the height of four hundred 
 and sixty feet. And in these American beds, separated 
 
 34
 
 398 DESCRIPTIVE SKETCHES FROM 
 
 from those of.the Dwinn, by a hundred and twenty degrees 
 of longitude, Pecten Islandicua^ Natica clausa^ Mya trun- 
 cata^ Saxicava rugosa^ and Tellina proxima, are the pre- 
 vailing forms. How very wide the geographic area which 
 these shells must have possessed of old ! A depression of 
 the North American Continent to the amount of but four 
 hundred and sixty feet would greatly affect its contour. 
 It would cut it off from South America (the highest 
 point over which the Panama Railway passed was but two 
 hundred and fifty feet over the level of the sea), and 
 unite the Atlantic and Pacific Oceans by a broad channel, 
 more than thirty fiithoms in depth. But from various 
 other appearances the American geologists claim for their 
 country a much greater depression than even that of Moel 
 Tryfon in Wales. It must have been depressed at least two 
 thousand feet, and a wide sea must have passed through 
 the valley of the Mississippi into what is now the Lake dis- 
 trict, and from thence into Hudson's Bay and the Arctic 
 Seas. And now, let the reader mark the probable effects 
 on the climate of Northern Europe generally, and on that 
 of Britain in particular, of so extensive a submergence of 
 the American Continent. 
 
 No Other countries in the world situated under the same 
 lines of latitude enjoy so genial a climate as that enjoyed 
 by the British islands in the present day. The bleak 
 coasts of Labrador lie in the same parallels as those of 
 Britain and Ireland ; St. John's, in Newfoundland, is situ- 
 ated considerably to the south of Torquay in Devon ; and 
 Cape Farewell, in Greenland, to the south of Kirkwall, 
 the capital of the Shetland Islands. But how very differ- 
 ent the climate of those bleak occidental lands, from that 
 which renders Great Britain one of the first of agricul- 
 tural countries! At Nain, in Labrador, situated in the
 
 A geologist's portfolio. 399 
 
 same latitude as Edinburgh, the ground frost at the depth 
 of a few feet from tlie surface never thaws, but forms an 
 ungenial rock-lilie subsoil, against which the laborer breaks 
 his tool, and over which the cereals fail to ripen. From 
 the northern coasts of Newfoundland, though lying under 
 the same latitudinal lines as the extreme south of England, 
 there forms in winter a thick cake of ice, which, binding 
 up the stormy sea, runs northwards and eastwards, and 
 connects, as with a long bridge, the north of Iceland with 
 the 7iorth of Newfoundland ; thus constituting a natural 
 isothermal line, which shows that the European island has 
 a not severer climate than the American one, though it 
 lies more than ten degrees farther to the north. And be 
 it remembered that, did climate depend exclusively on a 
 country's latitudinal position on the map, and its distance 
 from the sun, it is the climate of Northern America that 
 would be deemed the ordinary and proper climate, and 
 that of Northern Europe the extraordinary and excep- 
 tional one. Britain and Ireland owe the genial, equable 
 warmth that rij^ens year after year their luxuriant crops, 
 and renders their winters so mild that the sea never freezes 
 around their shores, not, at least directly, to the distant 
 sun. Like apartments heated by pipes of steam or hot 
 water, or greenhouses heated by flues, they derive their 
 warmth from a heating agent laterally applied ; they are 
 heated by warm water. The great Gulf Stream, which, 
 issuing from the Straits of Florida, strikes diagonally 
 across the Atlantic, and, impinging on our coasts, casts 
 upon them not unfrequently the productions of the West 
 Indies, and always a considerable portion of the warmth 
 of the West Indies, is generally recognized as the heating 
 agent which gives to our country a climate so much more 
 mild and genial than that of any other country whatever,
 
 400 DESCRIPTIVE SKETCHES FROM 
 
 similarly situated. Wherever its influence is felt, — and 
 it extends as far north as the southern shores of Iceland, 
 Nova Zembla, and the North Cape, — the sea in winter 
 tells of its meliorating effects by never freezing; it remains 
 open, like those portions of a reservoir or canal into which 
 the heated water of a steam-boiler is supposed to escape. 
 In some seasons, — an effect of unknown causes, — the 
 Gulf Stream impinges more strongly against our coast 
 than at others: it did so in 1775, when Benjamin Franklin 
 made his recorded observations upon it, — the first of 
 any value which Ave possess; and again during the three 
 mild winters that immediately preceded the last severe 
 one, — that of 1855, — and which owed their mildness 
 apparently to that very circumstance. It was found dur- 
 ing the latter seasons that the temperature of the sea 
 around our western coasts rose from one and a half to two 
 degrees above its ordinary average ; and it must be remem- 
 bered how, during these seasons, every partial frost that 
 set in at once yielded to a thaw whenever a puff of wind 
 from the west carried into the atmosphere the caloric of 
 the water over which it swept. The amount of heat dis- 
 charged into the Atlantic by this great ocean-current is 
 enormous. "A simple calculation," says Lieutenant Mau- 
 ry, " will show that the quantity of heat dischai-ged over 
 the Atlantic from the waters of the Gulf Stream in a win- 
 ter day would be sufficient to raise the whole column of 
 atmosphere that rests upon France and the British Islands 
 from the freezing point to summer heat." " It is the influ- 
 ence of this stream upon climate," he adds, " that makes 
 Erin the Emerald Isle of the sea, and clothes the shores 
 of Albion with evergreen robes ; while, in the same lati- 
 tude, on the other side, the shores of Labrador are fast 
 bound in fetters of ice."
 
 A geologist's portfolio. 401 
 
 Now, a depression beneath the sea of the Xorth Ameri- 
 can continent would have the effect of depriving northern 
 Europe of the benefits of this great heating current. Its 
 origin has been traced to various causes, — some of them 
 very inadequate ones. It has been said, for instance, that 
 it is but a sort of oceanic prolongation of the Mississippi. 
 It has been demonstrated, howevei-, that it discharges 
 through the Straits of Florida about a thousand times 
 moi'e water than the Mississippi does at its mouth ; and 
 yet, even were the case otherwise, and the view correct, 
 any great depression of North America would cut off the 
 Mississippi from among the list of great rivers, by convert- 
 ing the valley which it occupies into a sea, and Avould thus 
 terminate the existence of the Gulf Stream. The Stream 
 has, however, a very different and more adequate origin, 
 but one which the depression of the North American Con- 
 tinent would equally affect. It is a reaction on the great 
 Drift Current. If the reader take a cup or basin filled 
 with water, and blow strongly across the surface of the 
 fluid, two distinct currents will be generated, — a drift 
 current, which, flowing in the direction of his breath, will 
 impinge against the opposite side of the vessel, — and a 
 reactionary current, which, passing along its sides, will 
 return towards himself. And nothing can be more obvi- 
 ous than the principle on which this occurs. The drift 
 current, more immediately generated by his breath, heaps 
 up the water against the side of the vessel on which it 
 impinges ; and this heaped-uj) water must of course inevi- 
 tably seek to return to the other side, in oi-der to restore 
 the deranged equilibrium of level. Now, the Northern 
 Atlantic, — the Atlantic to the north of the equator, — 
 displays on an immense scale exactly the phenomena ex- 
 hibited by this simple experiment of the cup or basin- 
 
 34*
 
 402 DESCRIPTIVE SKETCHES FROM ' 
 
 The breath of the trade-winds, ever blowing upon it from 
 the east and north-east, in that broad belt which lies be- 
 tween the tenth and the twenty-sixth degrees of north 
 latitude, forms a great drift current, which, impinging on 
 and heaping up the waters against the South American 
 coast, — the opposite side of the cup or basin, — flows 
 northwards into the Caribbean Sea and Mexican Gulf, 
 and, issuing from the Straits of Florida in the character 
 of the reactionary Gulf Stream, strikes diagonally across 
 the Atlantic full on Northern Europe. But the existence 
 of this reactionary stream is not merely and exclusively a 
 consequence of the existence of the Drift Current : it is 
 also equally a consequence of the existence of an Ameri- 
 can continent. Save for the side of the basin or cuj) oppo- 
 site to that whence the breath comes, the water, instead 
 of returning in a reactionary current, would flow over. 
 Such a wide breach in the sides of the cup along the Isth- 
 mus of Panama, for instance, as a depression of but four 
 hundred and sixty feet would secure, would permit tLe 
 Drift Current to flow into the Pacific. Such a wide breach 
 in the sides of the cup along the valley of the Mississippi 
 as a depression equal to that indicated by the shells of 
 Moel Tryfon would secure, would permit the reactionary 
 Gulf Stream, though already formed, to escape, along what 
 is now the lake district of America, into Hudson's Bay. 
 In either case the Gulf Stream would be lost to Northern 
 Euro])e; and the British Islands, robbed of the Gulf 
 Stream, would possess merely the climate proper to their 
 latitudinal position on the map ; — they would possess such 
 a climate as that of Labrador, where, beneath seas frozen 
 over every winter many miles from the shore, exactly the 
 same shells now live as may be found, in the sub-fossil 
 state, in the Kyles of Bute, or underlying the pleasant
 
 A geologist's portfolio. 403 
 
 town of Rothesay. A submergence of the North Ameri- 
 can Continent would give to Britain and Ireland, with the 
 countries of Northern Europe generally, what they all 
 seem to have possessed during the protracted ages of the 
 Pleistocene era, — a glacial climate. 
 
 If our conclusions be just, — and we see not on what 
 grounds they are to be avoided, — our readers will, we 
 dare say, agree with us that it would not be easy to pro- 
 duce a more striking illustration of the influences which 
 are at times exerted by the conditions of one country on 
 those of another. Our brethren of the United States are 
 occasionally not a little jealous of the mother country ; but 
 we suspect all of them do not know how completely they 
 could ruin her could they but succeed in keeping their 
 great Gulf Stream to themselves. It might be unwise, 
 however, to urge matters quite so far, lest they should 
 provoke us, in turn, to demand back again the large brains 
 and high-mettled blood which we have most certainly 
 given them. Such of our readers as occasionally enjoy a 
 summer vacation on the west coast might find it no dull 
 or useless employment to begin reading for themselves the 
 shell inscriptions borne by the Pleistocene deposits. It 
 would at once form an excellent exercise in Conchology 
 and a first lesson in Geology, which, from the interest it 
 excited, would scarce fail to lead on to others. With their 
 eyes educated to the work, too, they would find, we doubt 
 not, the beds in many a new locality in which they had not 
 been detected before, and enjoy the same sort of pleasure 
 in falling upon a fresh deposit, as that enjoyed by an Egyp- 
 tian or Assyrian antiquary when he discovers a catacomb 
 of unrolled mummies never before laid open, or a series of 
 sculptures or of inscriptions in the cuneiform character, 
 unseen since the days of Semiramis or Sennacherib. We
 
 404 DESCRIPTIVE SKETCHES FROM 
 
 ourselves once enjoyed such a pleasure at Fairlie. We 
 laid open a noble bed, previously unknown, about a quar- 
 ter of a mile to the north of the village ; and from amid 
 great scalps of Pecten Jslcmdiciis, roughened on their 
 upper valves by huge Balonidae, and from beside thick- 
 lying groups of Cypinidae, we disinterred many a curious 
 boreal shell, — great massive Panopea, graceful Veneridea, 
 the Greenland Mya, and the Tellina of the North Cape ; 
 and beneath all we detected grooved and dressed rock- 
 surfaces, that bore their significant markings as freshly as 
 if the grating ice had passed over them but yesterday. 
 We would specially call the explorer's attention to the cor- 
 roborative evidence borne by appearances of mechanical 
 origin such as these to the mute testimony of the shells. 
 We have already incidentally referred to the interesting 
 deposits of Balnakaillie Bay. A stream falls into the sea 
 at its upper extremity, and exhibits, in the section which 
 it supplies, a bed charged with the old boreal shells, from 
 where it creeps out along the beach, till where we lose it 
 in the interior, far above the reach of the tide. As it 
 passes inwards, we find the old coast line deposits resting 
 over it ; in one place assuming the ordinary character of 
 a stratified sand and gravel ; in another existing as a par- 
 tially consolidated conglomerate ; while immediately be- 
 neath it, on the north side of the stream, the rock appears 
 strongly marked by the old glacial dressings. The me- 
 chanical and zoologic evidences of the existence of a 
 period of extreme cold thus lying side by side may be 
 studied together. But the district has its many such ap- 
 pearances. Not a few of the hills bear, in their rounded 
 protuberances and smoothed and channelled hollows, evi- 
 dence of the ice-agent that wasted them of old, and in 
 the valley of the Gareloch, only a few miles distant, Mr.
 
 A geologist's portfolio. 405 
 
 Charles Maclaren found unequivocal traces of an ancient 
 glacier. 
 
 But the collateral evidences would lead us into a field 
 quite as wide as that into which we have made our brief 
 excursion, and are now preparing to leave. The following 
 interesting extract from Mr. Kingsley's Glaucus, with 
 which we conclude, may at once show how rightly to read 
 these, and what very amusing reading they form. It is 
 thus we find Mr. Kingsley accounting, in light and grace- 
 ful dialogue, for the formation of a profoundly deep lochan 
 of limited area, tliat opens its blue eye to the heavens 
 amid the rough wilderness of rocks and hills that encircle 
 the gigantic Snowdop. 
 
 " You see the lake is nearly circular. On the side where 
 we stand the pebbly beach is not six feet above the water, 
 and slopes away steeply into the valley behind us, while 
 before us it shelves gradually into the lake ; forty yards 
 out, as you know, there is not ten feet of water, and then 
 a steep bank, the edge whereof we and the big trout know 
 well, sinks suddently to unknown depths. On the oppo- 
 site side, that vast flat-topped wall of rock towers up 
 ehoreless into the sky seven hundred feet perpendicular. 
 The deepest water of all, we know, is at its very foot. 
 Right and left two shoulders of down slope into the lake. 
 Now turn round, and look down the gorge. Remark that 
 the pebble bank on which we stand reaches some fifty 
 yards downward. You see the loose stones peeping out 
 everywhere. We may fairly suppose that we stand on a 
 dam of loose stones, a hundred feet deep. 
 
 "But why loose stones? and if so, what matter and 
 what wonder ? There are rocks cropping out everywhere 
 down the hill-side. 
 
 " Because, if you will take up one of these stones, and
 
 406 DESCRIPTI^rE SKETCHES FROM 
 
 crack it across, you will see that it is not of the same stuff 
 as those said rocks. Step into the next field and see. 
 That rock is the common Snowdon slate which we see 
 everywhere. The two shoulders of down right and left 
 are slate, too; you can see that at a glance. But the 
 stones of the pebble bank are a close-grained, yellow-spot- 
 ted Syenite; and where, — where on earth did these Syen- 
 ite pebbles come from ? Let us walk round to the cliff on 
 the opposite side and see. 
 
 "Now mark. Between the cliff-foot and the sloping 
 down is a crack, ending in a gully : the nearer side is of 
 slate, and the further side the cliff itself. Why, the whole 
 cliff is composed of the very same stone as the pebble 
 ridge. 
 
 " Now, my good friend, how did these pebbles get three 
 hundred yards across the lake ? Hundreds of tons, some 
 of them three feet long, — who carried them across ? The 
 old Cimbri were not likely to amuse themselves by making 
 such a breakwater up here in No-man's-land, two thou- 
 sand feet above the sea; but somebody or something must 
 have carried them, for stones do not fly, nor swim either. 
 
 " Let our hope of a solution be in John Jones, who car- 
 ried up the coracle. Hail him, and ask what is on the top 
 of that cliff. So? — 'Plains, and bogs, and another linn.* 
 Very good. Now, does it not strike you that the whole 
 cliff has a remarkably smooth and plastered look, like a 
 hare's run up an earth bank? And do you see that it is 
 polishfd thus only over the lake ? that as soon as the 
 cliff abuts on the downs right and left, it forms pinnacles, 
 caves, broken angular boulders ? Syenite usually does so 
 in our damp climate, from the weathering effect of frost 
 and rain ; why has it not done so over the lake ? On that 
 part something (giants perhaps) has been scrambling up
 
 A geologist's portfolio. 407 
 
 and down on a very large scale, and so rubbed off every 
 corner which was inclined to come away, till the solid core 
 of the rock was bared. And may not these mysterious 
 giants have had a hand in carrying the stones across the 
 lake? . . . Really, I am not altogether jesting. Think 
 awhile what agent could possibly have produced either 
 one or both of these effects ? 
 
 " There is but one ; and that, if you have been an 
 Alpine traveller, much more if you have been a chamois- 
 hunter, you have seen many a time (whether you knew it 
 or not) at the very same work." 
 
 "Ice! Yes: ice. Hrymin, the frost-giant, and no one 
 else. And if you look at the facts, you will see how ice 
 may have done it. Our friend John Jones's report of 
 plains and bogs, and a lake above, makes it quite possible 
 that in the ice-age (glacial epoch, as the big-word mongers 
 call it), there was above that cliff a great neve or snow- 
 field, such as you have seen often in the Alps at the head 
 of each glacier. Over the face of this cliff a glacier had 
 crawled down from that neve, polishing the face of the 
 rock in its descent ; but the snow, having no large and 
 deep outlet, has not slid down in a sufficient stream to 
 reach the vale below, and form a glacier of the first order, 
 and has therefore stopped short on the other side of the 
 lake, as a glacier of the second order, which ends in an 
 ice-cliff hanging high upon the mountain-side, and kept 
 from farther progress by daily melting. If you have ever 
 gone up the Mer-de-Glace to the Tacal, you saw a mag- 
 nificent specimen of the sort on your right hand, just 
 opposite the Tacal, in the Glacier de Trelaporte, which 
 comes down from the Aiguille de Charmoz." 
 
 "This explains our pebble ridge. The stones which 
 the glacier rubbed off the cliff beneath it, it carried for-
 
 408 DESCRIPTIVE SKETCHES FROM 
 
 wards slowly, but surely, till they saw the light again in 
 the face of the ice-cliff, and dropped out of it under the 
 melting of the summer sun, to form a huge dam across the 
 ravine ; till, the ' ice-age ' past, a more genial climate suc- 
 ceeded, and neve and glacier melted away; but the 
 * moraine ' of stones did not, and remains to this day, the 
 dam which keeps up the waters of the lake. 
 
 " There is my explanation. If you can find a better, 
 do ; but remember always that it must include an answer 
 to, — ' How did the stones get across the lake ? ' "
 
 RECENT GEOLOGICAL DISCOVERIES.* 
 
 PKEPAKATIONS FOR THE BRITISH ASSOCIATION MEETING Al 
 ABERDEEN IN 1859. 
 
 The gentlemen of the hammer and chisel must imme- 
 diately prepare a Reform Bill^ and readjust their nomen- 
 clature and classification. Both are uncouth and barbar- 
 ous, as well as unscientific. Recent discoveries have 
 unsettled almost every one of the characters and tests of 
 the age of rocks. Old Werner's Transition class, though 
 founded to some extent on facts, has been long ago dis- 
 carded. But will hardness or crystalline structure, or the 
 absence even of organic remains, hitherto described as the 
 grand features of the primitive class of rocks, now bear 
 to be trusted as essentialia of classification ! Every sum- 
 mer's ramble multiplies proofs to the contrary. The mere 
 \'icinity of a trap-vein, squirted from its boiling caldron 
 below, among the most sedimentary strata, has often baked 
 them into hard crystalline masses, and converted mud- 
 banks charged with shells into beautiful granular marble, 
 as may be seen at Strath, in Skye, under the overlying 
 igneous rocks of the Cuchullins. And perhaps the time is 
 not far distant when it may be difficult to find in the crust 
 of the globe any assemblage of rocks in which organisms 
 may not be detected, although heat^ for the most part, has 
 
 * See Introductory Re'sume, p. 30. 
 35
 
 410 DESCRIPTIVE SKETCHES FROM 
 
 nearly obliterated them.^ Again, a little more patient 
 investigation, we expect, will blow to the winds many a 
 fine theory as to the gradual development of species, and 
 will most likely show that at no former period was there 
 an ocean replete with shells and worms low in the scale of 
 organization, which had not on its shores a rich vegetation 
 and a fauna abomiding in reptiles, and perhaps birds and 
 quadrupeds! Thus, when Hugh Miller wrote his "Old 
 Red Sandstone," he described it as peculiarly a salt-ioater 
 fish formation, in which there were scarcely any shells or 
 vegetables, the faint traces of the latter which he had dis^ 
 covered being only markings of fucoids and similar sea^ 
 weeds. So far as then known, the Scottish Old Red 
 Sandstone was the produce of a deep shoreless ocean, to 
 which no decayed forests had been brought down by rains 
 and rivers to become future coal-fields, nor on whose 
 
 1 " The hypothesis," says Sir Roderick Murchison, in his newly-pub- 
 lished edition of " Sihiria," " that all the earliest sediments have been so 
 altered as to have obliterated the traces of any relics of former life which 
 may have been entombed in them, is opposed by examples of enormously 
 thick and often finely levigated deposits beneath the lowest fossiliferous 
 rocks, and in which, if many animal remains had ever existed, more 
 traces of them would be detected." 
 
 "And yet," as he again observes, " the fine aggregation and unaltered 
 condition of those sediments have permitted the minutest impressions to 
 be preserved. Thus, not only are the broad wave-marks distinct, but also 
 those smaller ripples which may have been produced by wind, together 
 with apparent rain-prints, as seen upon the muddy surface, and even 
 cracks produced by the action of the sun on a half-dried surface. Again, 
 as a further indication that these are littoral markings, and not the results 
 of deep-sea currents, the minute holes left by the Annelides are most con- 
 spicuous on the sheltered sides of the reptiles in each slab. 
 
 " Surely, then, if animals of a higher organization had existed in this 
 very ancient period, we sliould find their relics in this sediment, so admi- 
 rably adapted for their conservation, as seen in the markings of the little 
 arenicola, accompanied even by the traces of diurnal atmospheric action." 
 — " Siluria," pp. 20—27. L. M.
 
 A geologist's portfolio, 41] 
 
 margins and lagunes disported the amphibious crocodile 
 or other allied genera, who could leave the impress of 
 their feet or tails on the soft mud or sand. The formation, 
 in short, was considered very low down indeed, and nea* 
 the base of the platform of rocks in which rest entombed 
 the remains of the earliest races of organized creatures. 
 But what have the discoveries of the last six months 
 established? Why, this, that the Old Red Sandstone of 
 the east coast of Scotland is comparatively a modern 
 formation, — much newer, at least, than the grand and 
 lofty masses of the jiurple and red conglomerate of the 
 western coast, which they so greatly resemble, but upon 
 which Sir Roderick Murchison has now proved that an 
 extensive series of crystalline quartz-rocks, limestones, and 
 micaceous schists repose all greatly older than Hugh Mil- 
 ler's fish-beds ! The discovery a few yeai-s ago of a little, 
 frog-like, air breathing reptile in Morayshire (named the 
 Telerpeton Elginense)^ has been a bone of contention 
 among the savans, because, according to past theories, it 
 was not easy to admit that it could have lived at the date 
 of the deposition of the Old Red Sandstone ; and hence 
 very grave doubts were expressed about it, and much 
 anxiety shown to establish that it belonged to the car- 
 honiferous strata, or to a New Red Sandstone formation, 
 which, if it did exist in our district, would be most valua- 
 ble, from the salt and calcareous deposits in which it 
 usually abounds. But within the last month or so. Sir 
 Roderick Murchison, in company with the Rev. G. Gor- 
 don, of Birnie, made transverse sections of the whole 
 series of Morayshire freestones, from the edges of the 
 micaceous schist in the interior, to the maritime promon- 
 tories of Burghead and Lossiemouth, which convinced 
 thera that the whole red and yellowish sandstones of the
 
 412 DESCRIPTIVE SKETCHES FROM 
 
 province "are so bound together by mineral characters 
 and fossil remains, that they must all be grouped as Old 
 Bed or Devonian^ Nay, more than this, the views of the 
 Director-General of the Geological Survey have been con- 
 firmed and extended by the farther discovery oi foot-prints 
 in the Burghead sandstone, not only of a small reptile 
 like the Telerpeton, but of very large creatures, that in 
 their movements made enormous strides, and whose bushy 
 tails have left trails more distinct than the largest seals or 
 otters could do ! A well-known laborer in the English 
 deposits (S. H. Beckles, Esq.), whose discoveries, in the 
 Purbeck and Wealden beds, of the jaw-bones of most 
 gigantic reptilia, have been extensive and most important, 
 has recently examined the sandstone quai-ries at Burg- 
 head and Covesea, where he has discovered the most 
 undoubted foot-prints of both large and small animals ; 
 and he has sent an extensive set of specimens to London, 
 to be laid before the Geological Society at its winter meet- 
 ings. Other foot-marks (each having the impression of 
 three or four claws to it) have lately been seen by Sir 
 Koderick, Mr, Martin, of Elgin, and Mr. Gordon, and 
 specimens communicated by Mr. P. Duff; so that, in the 
 language of Sir Koderick Murchison's announcement to 
 the late meeting of the British Association at Leeds, "the 
 presence of lai-ge reptiles, as well as of the little Telerpe- 
 ton, in this upper member of the Old Red Sandstone, is 
 completely established." 
 
 We have not room enough at present to point out fur- 
 ther deductions from these facts, and from the discovery, 
 about three years ago, of Silurian fossils in the Southern 
 HighlaiMs and in Ayrshire. We allude to them only to 
 show that, as in the days of Ilutton and Playfair, the gran- 
 ite veins which traverse in all directions the schists of Gleo-
 
 A geologist's portfolio. 413 
 
 Tilt were the means of establishing the imiptive and 
 igneous origin of granite, so Scotland again turns out to 
 be the battle-field of our men of science, and that very- 
 great many things may be expected from the explorations 
 which undoubtedly will be made, in connection with the 
 next meeting of the association, to be held next autumn 
 at Aberdeen, under the eye of the Prince Consort, and at 
 which Sir Roderick Murchison, we are glad to understand, 
 is to take his place as vice-president in all the sections. 
 He is the senior of the three permanent trustees of the 
 Association, and one of the founders of the body in 1831, 
 of whom, strange to say, only five are now alive. In Sir 
 David Brewster the science of the south of Scotland will 
 be admirably represented and supported ; while Sir Rod- 
 erick, a Ross-shire man, an alumnus of the Inverness Acad- 
 emy (aye, and one who put shoulder to shoulder with the 
 Highlanders on Corunna's bloody sod), will represent the 
 land north of the Spey. 
 
 If we might suggest to those who will take the lead in 
 the arrangements for the Aberdeen meeting, we would say 
 that they ought, in the geological section, to prepare for 
 one excursion to Stonehaven, on the eastern coast, and 
 another to Cromarty and Eathie, the scenes of Hugh Mil- 
 ler's labors, on the north. 
 
 In Stonehaven bay, and arising out of the harbor, may 
 be seen large dykes of trap ascending the cliff and over- 
 spreading the sandstone strata like the branches of a palm 
 tree, and thence overflowing towards the very curious 
 quartzose conglomerate at Dunnottar Castle. On the other 
 or northern horn of the bay, irruptive or felspar rocks jut 
 up in great masses and promontories, shifting and disturb- 
 ing the sandstone strata ; and immediately beyond, these 
 latter give place to hard crystalline and vertical strata, as 
 
 35*
 
 414 DESCRIPTIVE SKETCHES FROM 
 
 to which the Association will have to decide whether they 
 are altered Silurian or true j^^'i^nitive rocks. 
 
 At Cromarty, the local authorities, we think, should 
 prepare for a visit from a large body of savans (which our 
 railway and steamers will render easy), by exploring some 
 new sections of the rocks on which Hugh Miller used to 
 work. Many of these, it is well known, are below high- 
 water mark, and are thus often covered by the sea ; while 
 almost all the nodules containing fossil-fish have been ex- 
 tracted and carried away. Some excavations in the strike 
 or line of the same rocks should be made inland, the gravel 
 and boulder-clay should be removed, a few layers of the 
 sandstone underneath loosened, and a few broad sheets of 
 the rock exposed in situ, and so left for the further exam- 
 ination of visitors, without the natural dip or contents of 
 the beds being at all interfered with. 
 
 EXTRACT PROM "FOOTPRINTS OF THE CREATOR," P. 199. 
 
 In my little work on the " Old Red Sandstone," I have 
 referred to an apparent lignite of the Lower Old Red of 
 Cromarty, which presented, when viewed by the micro- 
 scope, marks of the internal fibre. The surface, when 
 under the glass, resembled, I said, a bundle of horse-hairs 
 lying stretched in parallel lines ; and in this specimen alone, 
 it was added, had I found aught in the Lower Old Red 
 Sandstone approaching to proof of the existence of dry 
 land. About four years ago, I had this lignite put strin- 
 gently to the question by Mr. Sanderson ; and deeply inter- 
 esting was the result. I must first mention, however, that 
 there cannot rest the shadow of a doubt regarding the 
 place of the organism in the geologic scale. It is unequiv- 
 ocally a fossil of the Lower Old Red Sandstone. I found
 
 A geologist's portfolio. 415 
 
 it partially imbedded, with many other nodules half-disin- 
 terred by the sea, in an ichthyolitic deposit, a few hundred 
 yards to the east of the town of Cromarty, which occurs 
 more than four hundred feet over the Great Conglomerate 
 base of the system. A nodule that lay immediately beside 
 it contained a well-preserved specimen of the Coccosteus 
 decipiens / and in the nodule in which the lignite itself is 
 contained the practised eye may detect a scattered group 
 of scales of Dij^lacanthics^ a scarce less characteristic 
 organism of the lower formation. And what, asks the 
 reader, is the character of this ancient vegetable, — the 
 most ancient, by three whole formations, that has presented 
 its internal structure to the microscope ? Is it as low in 
 the scale of development as in the geological scale? Does 
 this venerable Adam of the forest appear, like the Adam 
 of the infidel, as a squalid, ill-formed savage, with a rugged 
 shaggy nature which it would require the suggestive neces- 
 sities of many ages painfully to lick into civilization ? Or 
 does it appear rather like the Adam of the poet and the 
 theologian, independent, in its instantaneously-derived per- 
 fection, of all after developments, — 
 
 " Adam, the goodliest man of men since bom 
 His sons ? " 
 
 Is this tissue vascular or cellular, or, like that of some of 
 the cryptogamia, intermediate ? Or what, in fine, is the 
 nature and bearing of its mute but emphatic testimony 
 on that doctrine of progressive development^ of late so 
 strangely resuscitated ? 
 
 In the first place, then, this ancient fossil is a true wood, 
 
 1 This alludes, of^course, to the development theory of the " Vestiges of 
 the Natural History of Creation."
 
 416 DESCRIPTIVE SKETCHES FROM 
 
 — a dicotyledonous or polycotyledonous Gymno sperm., 
 that, like the pines and larches of our existing forests, bore 
 naked seeds, which, in their state of germination, developed 
 either double lobes to shelter the embryo within, or shot 
 Dut a fringe of verticillate spikes, which performed the 
 jjame protective functions, and that, as it increased in bulk 
 year after year, received its accessions of growtli in outside 
 layers. In the transverse section the cells bear the reticu- 
 lated appearance which distinguish the coniferje ; the lig- 
 nite had been exposed in its bed to a considerable degree 
 of pressure ; and so the openings somewhat resemble the 
 meshes of a net that has been drawn a little awry ; but no 
 general obliteration of their original character has taken 
 place, save in minute patches, where they have been injured 
 by compression or the bituminizing process. All the tubes 
 indicated by the openings are, as in recent coniferae, of 
 nearly the same size ; and though, as in many of the more 
 ancient lignites, there are no indications of annual rings, 
 the direction of the medullary rays is distinctly traceable. 
 The longitudinal sections are rather less distinct than the 
 transverse one : in the section parallel to the radius of the 
 stem or bole the circular disks of the coniferte Avere at first 
 not at all detected ; and, as since shown by a very fine 
 microscope, they appe;ir simply as double and triple lines 
 of undefined dots, that somewhat resemble the stippled 
 markings of the miniature painter ; nor are the openings 
 of the medullary rays frequent in the tangental section (^. e. 
 that parallel to the bark) ; but nothing can be better de- 
 fined than the peculiar arrangement of the woody fibre, 
 and the longitudinal form of tlie colls. Such is the char- 
 acter of this the most ancient of lignites yet found that 
 yields to the microscope the peculiarities of its original
 
 A geologist's portfolio. 417 
 
 structure. "We find in it an unfallen Adam — not a half- 
 developed savage.^ 
 
 The olive-leaf which the dove brought to Noah estab- 
 lished at least three important focts, and indicated a few- 
 more. It showed most conclusively that there was dry- 
 land, that there were olive-trees, and that the climate of 
 the surrounding region, whatever change it may have un- 
 dergone, Avas still favorable to the development of vegeta- 
 ble life. And, further, it might be safely inferred from it, 
 that if olive-trees had survived, other trees and plants must 
 have survived also ; and that the dark muddy prominences 
 round which the ebbing currents were fist sweeping to 
 lower levels Avould soon present, as in antediluvian times, 
 their coverings of cheerful green. The olive-leaf spoke 
 
 1 On a point of such importance I find it necessary to strengthen my 
 testimony by auxiliary evidence. The following is the judgment, on this 
 ancient petrifaction, of Mr. Nicol, of Edinburgh, — confessedly one of our 
 highest living authorities in that division of fossil botany which takes 
 cognizance of the internal structure of hgnites, and decides, from their 
 anatomy, their race and family : 
 
 " Edinburgh, 19th July 1845. 
 " Dear Sir, — I have examined the structure of the fossil-wood which you 
 found in the Old Red Sandstone at Cromarty, and have no hesitation in stating, 
 that the reticulated texture of the transverse sections, though somewhat com- 
 pressed, clearly indicates a coniferous origin; but as there is not the slightest 
 trace of a disc to be seen in the longitudinal sections parallel to the medullary 
 rays, it is impossible to say whether it belongs to the pine or araucarian division. 
 I am, etc. William Xicol." 
 
 It will be seen that Mr. Nicol failed to detect what I now deem the discs 
 of this conifer, — those stippled markings to which I have referred. But 
 even were this portion of the evidence wholly wanting, we would be left 
 in doubt, in consequence, not whether the Old Red lignite formed part of 
 a true gymnospermous tree, but whether that tree is now represented by 
 the pines of Europe and America, or by the araucarians of Chili and New 
 Zealand. "Were I to risk an opinion in a department not particularly my 
 province, it would be in favor of an araucarian relationship.
 
 418 DESCRIPTIVE SKETCHES FROM 
 
 not of merely a partial, but of a general vegetation. Now, 
 the coniferous lignite of the Lower Old Red Sandstone we 
 find charged, like the olive-leaf, with a various and sing- 
 ularly interesting evidence. It is something to know, that 
 in the times of the Coccosteiis and Asterolcjns there existed 
 dry land, and that that land wore, as at after periods, its 
 soft, gay mantle of green. It is something also to know, 
 that the verdant tint was not owing to a profuse develop- 
 ment of mere immaturities of the vegetable kingdom, — 
 crisp, slow-growing lichens, or watery spore-propagated 
 fungi, that shoot up to their full size in a night, — nor even 
 to an abundance of the more highly organized families of 
 the liverworts and the mosses. These may have abounded 
 then, as now ; though we have not a shadow of evidence 
 that they did. But while we have no proof whatever of 
 their existence, we have conclusive proof that there existed 
 orders and families of a rank far above them. On the dry 
 land of the Lower Old Red Sandstone, on which, according 
 to the theory of Adolphe Brogniart, nothing higher than a 
 lichen or a moss could have been expected, the ship-car- 
 jienter might have hopefully taken axe in hand to explore 
 the woods for some such stately pine as the one described 
 by Milton, — 
 
 " Hewn on Nonvejnan hills, to be the mast 
 Of some great admiral."
 
 SIR RODERICK MURCHISON 
 
 RECENT GEOLOGICAL DISCOVERIES IN MORAYSHIRE. 
 
 At a meeting of the Geological Society of London, held 
 on the 15th December 1858, Part III. of a paper by Sir 
 Roderick Murchison, on " the Geological Structure of the 
 North of Scotland," was read. 
 
 Referring to his previous memoir for an account of the 
 triple division of the Old Red Sandstone of Caithness and 
 the Orkney Islands, Sir Roderick showed how the chief 
 member of the group in those tracts diminished in its 
 range southwards into Ross-shire, and how, when traceable 
 through Inverness and Nairn, it was scarcely to be recog- 
 nized in Morayshire, but reappeared, with its characteristic 
 ichthyolites, in Banffshire (Dipple, Tynet, and Gamrie). 
 He then prefaced his description of the ascending order of 
 the strata belonging to this gi-oup in Morayshire by a 
 sketch of the successive labors of geologists in that dis- 
 trict; pointing out how, in 1828, the sandstones and corn- 
 stones of this tract had been shown by Professor Sedgwick 
 and himself to constitute, together with the inferior Red
 
 420 DESCRIPTIVE SKETCHES FROM 
 
 Sandstone and conglomei'ate, one natural geological assem- 
 blage; that in 1839 the late Dr. Malcolmson made the im- 
 portant additional discovery of fossil fishes, in conjunction 
 with Lady Gordon Gumming; and also read a valuable 
 memoir on the structure of the tract, before the Geolog- 
 ical Society, of which, to his, the author's, regret, an ab- 
 stract only had been published. — {Proc. Geol. Soc. vol. iii. 
 p. 141.) Sir Roderick revisited the district in the autumn 
 of 1840, and made sections in the environs of P^orres and 
 Elgin. Subsequently, Mr. P. Duff of Elgin published a 
 " Sketch of the Geology of Moray," with illustrative plates 
 of fossil-fishes, sections, and a geological map, by Mr. John 
 Martin ; and afterwards Mr. Alexander Robertson threw 
 much light upon the structure of the district, particularly 
 as regarded deposits younger than those under considera- 
 tion. All these writers, as well as Sedgwick and himself, 
 had grouped the yellow and whitish-yellow sandstones of 
 Elgin with the Old Red Sandstone ; but the discovery in 
 them of the curious small reptile the Telerpeton Elgin- 
 e;ise, described by Mantell in 1851 from a specimen in Mr. 
 P. Duff's collection, first occasioned doubts to arise respect- 
 ing the age of the deposit. Still, the sections by Captain 
 Brickenden, who sent that reptile up to London, proved 
 that it had been found in a sandstone which dipped under 
 "Cornstone," and which passed downwards into the Old 
 Re<i series. Captain Brickenden also sent to London nat- 
 ural impressions of the foot-prints of an apparently rep- 
 tilian animal in a slab of similar sandstone, from the coast- 
 ridire extending from Burghead to Lossiemouth (Cum- 
 mingston). Although adhering to his original view re- 
 specting the age of tlie sandstones. Sir R. Murchison could 
 not help having misgivings and doubts, in common with 
 many geologists, on account of the high grade of reptile
 
 A geologist's portfolio. 421 
 
 to which the Telerpeton belonged ; and hence he revisited 
 the tract, examining the critical points, in company with 
 his friend the Rev. G. Gordon, to whose zealous labors he 
 owned himself to be greatly indebted. In looking through 
 the collections in the public Museum of Elgin, and of Mr. 
 P. Duff, he was much struck with the appearance of sev- 
 eral undescribed fossils, apparently belonging to reptiles, 
 which, by the liberality of their possessors, were, at his 
 request, sent up for inspection to the Museum of Practical 
 Geology. He was also much astonished at the state of 
 preservation of a large bone {ischium) apparently belong- 
 ing to a reptile, found by Mr. Martin in the same sand- 
 stone quarries of Lossiemouth in Avhich the scales or scutes 
 of the Stagonolepis, described as belonging to a fish by 
 Agassiz, had been found. On visiting these quarries, Mr. 
 G. Gordon and himself fortunately discovered other bones 
 of the same animal ; and these, having been compared 
 with the remains in the Elgin collections, have enabled 
 Professor Huxley to decide that, with the exception of the 
 Telerpeton, all these casts, scales, and bones belong to the 
 reptile Stagonolepis Mobertsoni. Sir Roderick, having 
 visited the quarries in the coast-ridge, from which slabs 
 with impressions of reptilian foot-marks had long been 
 obtained, induced Mr. G. Gordon to transmit a variety of 
 these, which are now in the Museum of Practical Geology, 
 and of which some were exhibited at the meeting. 
 
 After reviewing the whole succession of strata, from the 
 edge of the crystalline rocks in the interior to the bold 
 cliffs on the sea-coast, the author has satisfied himself that 
 the reptile-bearing sandstones must be considered to form 
 the uppermost portion of the Old Red Sandstone, or Dev- 
 onian group, the following being among the chief reasons 
 for his adherence to this view : — 1. That these sandstones 
 
 36
 
 422 DESCRIPTIVE SKETCHES FROM 
 
 have everywhere the same strike and dip as the inferior 
 red sandstones containing Holoptychii and other Old Red 
 ichthyolites, there being a perfect conformity between the 
 two rocks, and a gradual passage from the one into the 
 other. 2. That the yellow and light colors of the upper 
 band are seen in natural sections to occur and alternate 
 with red and green sandstones, marls, and conglomerates 
 low down in the ichthyolitic series. 3. That while the 
 concretionary limestones called " Cornstones " are seen 
 amidst some of the lowest red and green conglomerates, 
 they reappear in a younger and broader zone at Elgin, 
 and reoccur above the Telerpeton-stone at Spynie Hill, 
 and above the Stagonolepis-sandstone of Lossiemouth; 
 thus binding the whole into one natural physical group. 
 4. That whilst the small patches of so-called "Wealden" 
 or Oolitic strata, described by Mr. Robertson and others, 
 occuring in this district, are wholly unconformable to, and 
 rest upon, the eroded surfaces of all the rocks under con- 
 sideration, so it was shown that none of the Oolitic or 
 Liassio rocks of the opposite side of the Moray Frith, or 
 those of Brora, Duni'obin, Eathie, etc., which are charged 
 with Oolitic and Liassic remains, resemble the reptiliferous 
 sandstones and " Cornstones" of Elgin, or their repetitions 
 in the coast-ridge that extends from Burghead to Lossie- 
 mouth. Fully aware of the great difficulty of determin- 
 ing the exact boundary-line between the Uppermost Devo- 
 nian and Lowest Carboniferous strata^ and knowing that 
 they pass into each other in many countries, the author 
 stated that no one could dogmatically assert that the rep- 
 tile-bearing sandstones might not, by future researches, be 
 proved to form the commencement of the younger era. 
 
 Sir Roderick concluded by stating that the conversion 
 of the Stagouolej)is into a reptile of high organization,
 
 A geologist's portfolio. 
 
 423 
 
 though of nondescript characters, did not interfere 
 
 WITH HIS LONG-CHERISHED OPINION FOUNDED ON AC- 
 KNOWLEDGED FACTS AS TO THE PROGRESSIVE SUCCES- 
 SION OF GREAT CLASSES OF ANIMALS, and that, inasmuch 
 as the earliest trilobite of the invertebrate Lower Siluriaji 
 era teas as wonderfully organized as any living Crusta- 
 cean, so it did not unsettle his belief to find that the earli- 
 est reptiles yet recognized, — the Stagonolepis and Telerpe- 
 ton, — pertained to a high order of that class. 
 
 At the same meeting, papers were read " On the Stago- 
 nolepis Hobertsoni of the Elgin Sandstones, and on the 
 Footmarks in the Sandstones of Cuminingston," by Mr. T. 
 H, Huxley ; as well as one " On Fossil Foot-prints in the 
 Old Red Sandstones at Cummingston," by S. H. Beckles, 
 Esq.
 
 c^
 
 000 684 248