REPORT OF THE REGENTS OF TIlE UNIVERSITY
ON TIIE
New York State Cabinet of Natural History for 1867.
AP P E: IN D I X:E.
ON T'IE
IAURENTIAN LIMESTONES
OF
NORTH AMERICA
T. STERRY  HUINT, L L.D., F. R. S.
REPRINTED WITH ADDITIONS FROM THE REPORT OF THE
GEOLOGICAL SURVEY OF CANADA FOR 1863-66.
ALBANY:
VAN BENTHUYSEN PRINTING HOUSE.
1871.








(E.)
ON THE MINERALOGY OF THE LAURENTIAN
LIMESTONES OF NORTH AMERICA.
By T. STERRY HUNT, LL. D., F. R. S., of the Geological Survey of Canada.
INTRODUCTION.
In a general report of the Geological Survey published in 1863,
under the title of the Geology of Canada, the ancient gneissic system of the Laurentides of Canada and the Adirondacks of New
York, is described under the name of the Laurentian system. Farther researches have shown that under this title were included two
distinct and unconformable groups of rocks, which have since been
distinguished as the Lower Laurentian and the Upper Laurentian,
or Labrador series.  The first and most ancient of these, to which
it will be well for the future to restrict the name of Laurentian,
corresponds to the primitive gneiss of Scandinavia and of the
west of Scotland.  This opinion was put forwatrd by the author
in 1855, and has since been confirmed by Sir R. I. Murchison, for
Scotland.  More recently, Messrs Gwiimbel and Hochstetter, after
a lengthened study of the older gneiss of Bavaria and Bohemia,
have declared it to be identical with the Laurentian of North
America, a conclusion sustained by the discovery by Giimbel of
the fossil remains of the rhizopod Eozoon, CCanadense, in the limestone of the Bavarian gneiss.
The lower or true Laurentian consists in great part of orthoclase
gneiss, sometimes granitoid, with quartzites, occasionally becoming conglomerates; hornblendic and micaceous schists, pyroxenites, serpentines and limestones, sometimes magnesian.  These
limestones, generally very crystalline, are seen on the Ottawna, in




4         TWENTY-FIRST REPORT ON THE STATE CABINET.              [48]
the counties of Argenteuil and Grenville, to form  three distinct
formations,  having each a thickess of fi'romlll  1,000 to 1,500 feet,
separated, underlaid and overlaid by still greater imiasses of gneiss
and quartzite.   The measuilred  thickness of this series on the
Ott-awa is more than 20,000 feet, which is l)rolbal)ly fiar from representim(,r its total volume, wvlile in Bohemia it is supposed to equal
not less than 90,000 feet.  In the coullnty of Hastins, in the pr)ovince of Onitario, not less than 21,000 feet of strata, consisting of
crystalline schists, limestones and (liorites, are found resting confo(rmlably upon Laurentian gneiss.*  It al)pears certain, however,
that this series, which differs both in the succession and the lithological character of its strata fronm the sections in the Ottawa
valley, belongY to the Lower Lanlrentian, of which it would lappear
to colnstitute a meml)er higher in the system  than anly observed in
New York or in the province of Quebec, so that the wvhole known
tlhicklless of the Lowcer Laurentiall in Canad would surpass 40,000
feet.  The Eozoot C(tracadense is met with in several localities, both
in the lower and higher memblers of the Lower Laulrelntian.
The Labrador (or Upper Laurentian) occurs in detached areas,
resting  unlconfolrnlably ul)on the true La:urentian system.  Soime
ot these areas are mally miles inl lreadth, lind they occur at
intervals in Canada from the shores of L(ake Huron to the coast of
Labrador.  The Labradl.    r series contains strata of orthoclase
gneiss, quarltzites, and crystalline limestones; but its predominiant element is an anortholite-a rock composed essentially of a
feldspar of the anorthic or triclinic system, generally with a sl:mall
admixture of pyroxene or hypersthelle.  This anortholite is sometimes grleissoid, anlld even fille-graine; )ut is imore often grlntlitoi d,
and occasionally  presents large el. avable maIsses of opalescent
fcullp1ar, generally lahradorite or andesine.  The thickness of this
l)labr;:dor serlies crlnot be less than 10,000 feet, and is perhaps
much more.  The true Lauirentianl offers nothing similar to these
alnortlolites, lwhich seem to be) identical, both  lithologically.and
geoglnostica.lly, wvith the norites of Norway.  They are the hypersthenites of the Hebrides, described bly McCullo ch, and subsequently recognized by Emmons under the name of hypersthene
rock in the Adir'onldacks, of which, accorcdiTng to him, they form1
sonme of the highest summits.
To these two great series of ancient rocks must be added a
third —the Hiuronia,  which attains on Lfake Huron a thicknless of




[49]       LAURENTIAN LIMESTONES OF NORTII AMERICA.                  5
not less than 18,000 feet, wherle it lies between the Laii rentilan and(
Siluriian systems, conilfonimalle with neither.  It is believed to lbe
newer thall the La(l)ador series, though the two have never yet
been seenl ill coIntact.  The recent observations of Prlof. Hall, lhave
shown that the Huronian system is found interposed between the
Siluriall and the Laurentian to the west of the Mississippi, while
it appel)lrs to have beein very  recently identified both in Newfoundland l and in New  BLrunswick.  Of these three great series,
Sit  William Logan remarks that their united thickness " may possiblly fair surpass that of a1ll the succeeding rocks friom the base of
the Potsdam series to the present time.  We are thuls carried black
to a period so far:emnote, that the appearance of the so-called pl'imordial fatnna may by some be considered a comparatively modern
event.  We filnd, however, that even dLuring   the Laurentian period,
the same chemical andl mechanical processes which have ever sitnce
been at work disintegratinlg and rlecoiistructtilng the earth's crust,
were itn operation, as now.  In the congilomeraltes of the lliiu'oniaiit
series, there arie enclosed boulders deirived firomr  the Laurentian,
that seemmi to show that the parent rock was alteredl to its presenlt
crystalline conditioll before the deposit of the newer fornratioll,
while illterst, yatified with the  Laurenti-an  limestones, there  1 are
beds of conglonierate, the pelbbles of which are themselves rolled
fragnments of a still older laminlated sanid-rock; and the foirmation of these b)eds leads us still furlther into the past." (Qltar. Joto.
C(ecl1. Soc., February, 1865.)
The area occupied iby the Laulrenltian  rocks ill Canada, is about
200,000 square miles, of which ablout 1,500 square miles ha.ve
l)een accurately stludied alld mapped ill the valley of the Ottawa,
ill the province  of Quelbec, and a: still smaller area in the county
of Hastings, Onitario.  The Laul'entilan area( of the Adirolldacks,
in northern New Yoirk, coilmpr ises ablout 10,000 square mniles, but
has never yet been stratigraphically stidied. althoillih mnuch llttention has leeni paid to the mineralogy of the limestoines of the series,
which preseint mainy characters )oth of scielltitic alld of economic
interest.  Thle following )pages are extracted froml  thle Report of
the Geological Survey of Canacda for 1863-66 (pages 182-223),
pullished at. Ottawa, and heire reprinted wvithl sonme few additiols,
which are distinluishled'by being enclosed in b-rackets:
The evidence afforded by the careful  stratigraplhical study of
these Laurentian limestones, and their associated rocks in tile vatl



6        TWENTY-FIRST REPORT ON THE STATE CABINET.    [50]
ley of the Ottawa, left, as we have seen, no doubt of their sedimentary nature and origin.  Similar limestones in the Highlands
of New  York and New Jersey were long since recognized by
Rogers, by Mather, and by other American geologists, as in like
manner altered stratified rocks, which were by some regarded  as
of Silurian age, and by others of greater antiquity.  The observations made by Sir WMilliam Logan andcl Prof. James Hall, in
1864 (Amer. Jour. Science [2], xxxix, 97), in the Highlands of
the Hudson, however, leave no doubt that these limestones, and
their accompallying gneissoid strata, belong to the Laurentian
syistevm.
The study by the late Dr. Emmons of the similar series of rocks,
constituting the mountain region of the Adirondacks in northern
New York, and continuous with the great Laulentian area of
Canada, led him, however, to regard the liniestomnes of the series
as of igneous origin, and in fact as intrusive rocks.  (See his
Report onl the Geology of the First District of New York, published in 1842, pages 37-59.)  This view, althoulgh in contradiction with the conclusions of other geologists who have examined
these Laurentian limestones in Canada and the United States, was
not so singular as might at first sight appear.  Mather, in his
Report on Second District of New York (page 485), while maintaining the sedimentary and metamorphic nature of the crystalline
limestones of the Highlands, asserted that there were examples in
Washingtonl county  fully sustainling Emmons' view that such
limestones sometimes occur as eruptive rocks.
Many of the first geologists of other countries have also maintained the igneous origin of certain crystalline limestones.  Thus,
in 1863, we find Von Leonhard asserting that limestones have
sometimes come from the interior of the earth in a liquid state, like
other igneous rocks.  A similar view was at that time maintained
by Guidini with regard to the dolomites of Spezzia in northern
Italy, and by Rozet for similar rocks at Oran in Algeria, and for
the crystalline limestones of the Vosges, which, like those of the
Laureltian series, occur in gneiss, and are often mingled with serpentine.  (Bull. Soc. Geol. de France, iii, pages 215 and 235.)
These observers, like Dr. Emmonos, urged in support of their view,
among other reasons more or less fallacious, the undoubted fact
that such limestones, in some cases, apparently form  dykes or
veins, which, like those of granite and greenstone, traverse gneissic
o1' ouartzose strata.




[51.]     LAURENTIAN LIMESTONES OF NORTII AMERICA.            7
It has been pointed out in the Geology of Canada (pages 28
and 643), that, in the case of the Laurentian limestones, there is
abundant evidence that they were at one time in such a plastic condition that external forces were able, not only to contort great
masses of limestone, and to break and fold in a remarkable nmanner
certain interstratified quartzose layers, but to force the softened
limestone into fissulres in the adjacent silicious strata.  Examples
of the latter phenomenon are, however, comparatively rare, and
the limestone veins upon which Mr. Emmons, and probably other
olbservers, have founded their view of the igneous originl of cr1ystalline limestone, remain to be described, after a brief account of
the limestones and their immediately associated strata.  It should
here be mentioned that Bischof considers the great dykes of granular limestone, which, near Auerbach in the Bergstrasse, are met
with traversing gneiss, to be deposits fiom water, filling up fissures; in fact, veritable veinstones. (Chem. Geol., English Ed., iii,
pp. 148-150.)  See also the note on page 47 for a description of
a similar calcareous vein.. The Laurentian limestones of North America, and other crystalline limestones in different regions, some of which belong to
other geological periods, often abound, as is well known, in foreign
minerals. These occur disseminated through the mass of the rock,
of which they serve, in many cases, to mark the lines of stratification.  While some beds consist of nearly pure, carbonate of lime,
others will be found to be characterized by an admixture of grains
or crystals of chondrodite, pyroxene, serpentine, mica, feldspar,
quartz, graphite, or other minerals, either alone or variously associated, and sometimes in such quantities as to make up a large
proportion of the rock.
Recent investigations have shown that in some cases the dissemination of certain of these minerals through the crystalline
limestones is connected with organic forms.  The observations of
Dr. Dawson and myself on the Eozoon Canadense showed that
certain silicates, namely, serpentine, pyroxene and loganite, had
been deposited in the cells and chambers left vacant by the disappearance of the animal matter from  the calcareous skeleton of
that foraminiferous organism, so that when this calcareous portion
is removed by an acid there remains a coherent mass, which is a
cast of the soft parts of the animal, in which n: t only the chanmbIers and connecting canals, but the minute tubuli and pores are
represented by solid mineral silicates.  It was shown that this




8         TWENTY-FIRST REPORT ON TIIE STATE CABINET.           [52]
process must have taken place durilng  the life of the animal or
immnne(liately after its death, and must have depended upon the
deposition of these silicates fronml the waters of the ocean.
The train of investigationl thus opened up has lbeen pursued by
Dr. Giimnlel, Director of the Geological Survey vf Bavaria, who,
ill a: recent remarkable memoir presented to the Royal Society of
that COllntry, has detailed. his results.
IHavingr first detected a fossil identical with the Canadian Eozoon
(together with several other curious microscopic organic forms not
yet observed in Canada), replaced by serpentine in a crystalline
limestone fiom the primitive gneiss of Bavaria, which lhe identifies with the Laurentian system of this country, he next discovered
a1 related organism, to which he has given the name of E'ozooni
Bactcto'icu't.  This occurs in a crystalline limestonle b1elolnging to a
series of rocks more recent than the Laurentianl, bit older thtan the
primordial zone of the Lower Silurian, and designated by him the
lIerciynian clay-slate series, which he conceives may represent the
Canbri)'ian system of Great Britain, and perhaps correspond to the
Hulronian series of Canada aiid the United  Staltes.  The cast of
the sotft parts of this new fossil is, accordingy to Gumbel, in part
of serpentine and in part of hornblende.
His attention was next directed to the green hornblende (pargasite), which occurs in the crystalline limestone of Pargas, in Finland, (land remains, when the carbonlate of lime is dissolved, as a
coherent mass, closely resemblilng that left by the irregular or
acelrvulille varieties of EJozoon.  These grains are described as
somewhat cylindrical in forlm, with roullnded and pitted surftlces,
presenting re-eentering angles, and resembling, on a small scale,
the tubers of some plants.  Though  thus destitute of external
crystalline forLm, they have a perfect cleavage. and are entirely
crystalline within.  These small tuberculated grainls are joined
together by sholt cylinders, and are occasionallly traversed by cylindiical openings; blesides which, there are implantell uponl them
small cylinders, often bralnched, and resembling exactly in size and
arratgemenlt the casts of the tubuli of Eozoon, in which, or in
some related( organic structure, he conceives the )argasite to have
been moulded.  A white mineral, probably seapolite, was found
to constitute some tulercles associated with thle pargasite, and the
two mineral species were in some cases united in the same rounded
grain1.
Similtar observations   were made lby him upon specimens of coc



[53]      LAURENTIAN LIMESTONES OF NORTH AMERICA.                9
colite, or green pyroxene, occuIinll  in rounded and wrinkled
grains inl a Laurentian limestone from New York.  These, according to Giimbel, present the same connecting cylinders and branching stems as the pargasite, and are by him supposed to have bleenl
moulded in the same mranlner.  The continuity of the casts of the
tulbuli appears to have been, for the most part, destroyed by the
subsequent crystallization of the carbonate of lime. in more compact l)o(rtions of which they are, however, occasionally preserveld.
The fine residue from the solution of the lime in acids gave other
minute organic forms, similai- to those noticed by him  in the
Eozoon limestone of Bavaria.  Very beautiful evidences of the
same oroanic structure, consistingt  of the casts of tululi and their
ramifictations, were also observed by G iinl)el in a finely clystalline
limestone, enclosing granules of chondrodite, hornblenllde, and
galrnet, from  Boden, in Saxony.  Other specimens of limestolle,
both with and without serpentine and chondrodite, were examined
without exhil)iting any traces of these peculiar forms, and these
negative results are justly deemed by Guimbel as going to prove
that their structure is really, like that of Eozoon, the result of the
intervention of organic f(:crmS.  In this connection, an observatioll
made by Sir William  Logan with regard to the Eozoon rock of
Canada is very important, namely: that the granular mixture of
carbonate of lime and serpentine whlich accompanies the pelfect
fo)rms of Eozoon, consists of broken and comminuted portions of
the fossil, still exhibiting minute structure, and having a stratifiecl
arrangement.  Besides the minerals mentioned above as haviing
been observed as the replacing substance of the Eozoon in Canada,
namely, serpentinle, pyroxene, and lo(anite, Giimbel adds chondrodite, horlnblende, scapolite (?), and probably, also pyrallolite,
quartz, and iolite or dichroite.
Accompanying the crystalline limestones of the Laurentian system in Canada, are often found strata made up of foreign minerals
to the entire exclusion of carbonllate of lime, by an admixture of
which, however, they gradually pass into the adjacent limestones.
These strata generally  consist of pyroxene, sometimes nearly
pure, and at other times mingled with mica, or with quartz and
orthoclase, often associated with hornblende, epidlote, ma'gnetite,
sphcne and graphite.  These beds, which may for the most pai't
be described as pyroxenites, from  the prevailing mineral, andi
which have been briefly noticed in the Geology of Canad3a, paL  e
2




10      TWENTY-FIRST REPORT ON THIE STATE CABINET.    [54]
475, are generally granitoid or gneissoid in structure.  They are
sometimes fine grained, and at other times made up of crystalline
elements firom two-tenths to five-tenths of an inch in diameter.
They occasionally assume a great thickness. and are then often
interstratified with beds of granitoid orthoclase gneiss, into which
the quartzo-felspathic pyroxenites pass by a gradual disappearance
of the pyroxene.  These peculiar strata, which contain at the same
time the minerals of the associated gneiss and of the limestones,
may thus be looked upon as beds of passage between the two
rocks.  Their mineral species and varieties, so far as my observations go, are identical with those of the limestones themselves.
It should be remembered that, besides the minerals already mentioned as predominating in these strata, other species characteristic of the limestones, such as serpentine and magnetite, sometimes
make up by themselves great beds in these intermediate or transition strata, which, from their mineralogical relations, may all be
looked upon as related to the accompanying limrnestones.  In some
districts, however, hornblende predominates over the pyroxene,
and gives rise to beds of pure hornblende rock, or amphibolite,
sometimes schistose, alld to compound rocks, such as diorite and
hornblendic gneiss, so that each group of limestones, with its
attendant pyroxenites, amphibolites, serpentines, magnetites, etc.,
may be considered as chlaracterizing an epoch in the geological
period to which it belongs.
Each one of the three great limestone formatiolns which have
been recognized in the Laurentian system on the Ottawa, appears
to be associated with these related rocks, which are, however, in
some parts, developed to a great exlent, and in others are comparatively unimportant in volume.  These limestone groups, as
we may hereafter designate the limestones with their attendant
rocks, appear to be the parts of the system to which the principal
economic minerals belong.  The ores of iron, col)per, nickel anld
cobalt, the apatite, mica and plumbago, as well as the serpentines
and the marbles of the great Lower Laurentian series, belong, so
far as yet known, to the limestone groups.
The Labrador or Upper Laurentian series includes one, and perhaps more limestone bands, which, so far as ascertained, present
the same mineralogical accompaniments as the limestone formations of the Lower Laurentian.
MINERAL VEINS.
WTe may now consider the mineral veins which tlraverse the




[55]       LAURENTIAN  LIMESTONES OF NORTI AMERICA.                       11
Laurentian rocks, and have chiefly been studied in connection with
these limestone groups, where they present the most varied and
important mineralogical characters.  These veins have been briefly
described ill the Geology of Canada, pages 35-37, where three
classes of them  are distinguished as follows:
1. Veins filled chiefly with calcareous spatr, sometimes with sulphate of barytes or fluor-spar, and carrying sulphuret of lead, and
more rarely, sulphurets of zinc, iron and copper.  Numbers of
these metalliferous veins have been described in speaking of the
various  metals in  chapter xxi of the  Geology, and  others are
noticed by Mr. Macfarlane in his report on the county of Hastings
(Geol. ASu'vey  of Canada, 1866).  These veins are much newer
than the Laurentian rocks, since they traverse in Ramsay, Ontario,
the  strata of the  Calciferous formation (Geol. Can., page  636).
Similar veins are also met with in Lewis county, New York, intersecting  the  limestones  of the  Trenton  group, and  sometimes
containing fluor-spar.  The vein in the Laurentian limestone on
Muscalunge lake, St. Lawrence county, New York, which contains
besides calcite, the hluge crystals of fluor-sparl so well known to
nmineraloists, may probably blelong to the same class as the leadbealaing veins just mentioned.*
2. The veins of the second class are filled  with  quartz  and
orthoclase feldspar, which is sometimes replaced by, or associated
with albite.  These veins occasionally include crystals of black or
white mica (muscovite), larrge crystals of black hornblende, and
not unfiequently black tourmaline, red garnet and zircon.  One
of this class, cuttingo  the Laurentian guneiss in Greenfield, near
Saratoga, New  York, contains, in addition to garllnet and tourmaline, the rare species chrysoberyl; and the grallitic vein holding
crystals of beryl, observed by Dr. Bigsby in the gneiss of Rainy
* In this connection may be mentioned a vein of this class, remarkable for its size, which
occurs at Spencerville, near Prescott, Ontario, and has attracted some attention in the
neighborhood. It is on the east half of lot twernty-eight, in the sixth range of Edwardsburg, and cuts the horizontal strata of the Calciferous formation, which is here bare of
soil, and holds nodules of chert. The vein, which runs E. N. E., has been traced on the
surface for a distance of about one hundred rods, and at the place where it has been
opened is not less than eighteen feet wide, and vertical in its attitude. A pit had been
sunk on the vein at the time of my visit, in August, 1864, to depth of twenty feet. The
veinstone was pure white crystalline carbonate of lime, without any traces of banded structure; and in detached blbcks the greater part of it could not be distinguished from many
saccharoidal limestones. Occasionally, however, masses of a coarsely cleavable and lilaccolored calcite were met with. The only foreign minerals in this vein were small and rare
grains of copper pyrites, and more frequently, iron pyrites in thin testaceous crusts, also
very sparsely distributed. Another, and a smaller vein, was observed nearly parallel to
this, filled with a similar carbonate of lime, but without any visible metallic impregnation.




12        TWENTY-FIRST REPORT ON THE STATE CABINET.             5 6]
Lake, possibly belongs to Laurelltian rocks (Geol. Can., page 492).
These veins, fiom. their constituent minerals, are generlally described as granitic, but are not to )be confounded with injected
gralllite dykes, since they are doubtless true veins, like those of
the first class, filled bly the gradual deposition of matters from
aqleoous sotutions.  These gllanitic veins, unlike those of tlhe preceding class, have not been observed to intersect the Silurian
rocks, and are probably of greater antiquity than they.  As will
hereafter be shown, they cannot be distinguished. from  the veins
of the third class, into which they pass bly insensible degrees.
3. In the third class were includedl, in the Geology of Canaida,
those veins which appear to l)e more, nearly related to the limestone groups, with which they are generally associated, and with
the characteristic minerals of which they are tilled. These veins are
extremely numerous, anlld exhliit, withill certain limits, remarkablle
variations in mineralogical characters.  The n:ost importallt elements of these veins are calcite, quartz, orthoclase, pihlotopite,
pyroxene, apatite and graphite, of whichi some e oler more will
be found to plrevail; but they may contain, besides, nullerlous
other species, including nearly every one to be miet with in the
limestonles, and in their accompanyillg  pyroxcnic and  rlneissic
rocks.  Veins of the present class are found traversing tall these
strata; they are most frequently vertical in attitude, and generally
cut the beds at righllt anlles, thoutoh to this many exceptions may
b)e cited.  They exhibit, within certain limits, great variations in
their mineralogical characters, not only in different veins, but in
different parts of the same veini.  Thuis, in some cases, pyroxcne
is the plredomilnant mineral, and other species are present onily in
small quantities.  At other times, orthoclase, aplatite, or mnagnesian micaL makes tup the great mass of the vein. and ill other cases,
calcareous spar.  It is the veins of this latter mlileral which have
doubtless been, l)y Emmoons and other observers, described las
inltl'usive veins of crystalline limestone. Having generally a solidly
crystalline lamellar strnlcture, very unlike the mIore or less caver'ious calcareous veinstones of the first class, anld sometimes
holding only sparsely disseminated crystals of one or more of the
minerals which are comnmon to the stratified limestones, such as
pyl'oxele, mllica, or al)atite, the observer will oftenl find it difficult
to determine whether a detached  lmass, or anl imperfectly displayed out-crop of crystalline linmestone, lelongs to a bed or a
veinl.  Whlen, however, it is p)ossible to make a throlugh exanii



[;/]      LAURENTIAN  LIMESTONES OF NORTH AMERICA.                  13
nationl of the locality, it will lIc fouind in the latter case tha;t the
deposit occuirs in a1 fissure cuttig)r the stratification, atid as welldefined walls.
A banded  aLrrallngement of the mineral contents is often very
well mnnarked.  Thus, while the walls mnay lbe coated with crystalline hol'ol)lendei, or wiphioopite, the l)ody of the vein will be
filled wvith al)atite, in the midst of which may )be found a mass
of crystalline orthoclasc, or of log(aniite, occuplying the centre of
the veiu.  Ill other istancCes, portions of the vein will ble occupied(
by crystals of apatite, pyroxerne, or lphlogopite, imbeldded in calcareous sl)par, which, inl some other part of the breadth of the veil.
or in its p)rolongationl, will so far prelominate as to give to the
mnass the aspect of a coarsely  crystalline  laniellar limestone.
Most of the well crystallized minerals described by oblservers,
both oil this continent and in Europe, as occurIiln in cr'ystalline
limestonics, appear to be derived fiom calcareous veins like those
just described.
In like manner I have descrlilbed localities of cryvstallized al)atite
as occuring in beds of limestones ill Burgess, Olltario, where a
subsequellt examination (while confirming the  existence of this
milleral in the limestone bIeds of that region) has shown, nevertheless, that the worlkable deposits are with few, if any, exceptions
confined to the veinistones.
From a lithological point of view, there cannot be allny objection
to extending the name of limestone to these calc:ateous veinstones;
but geologiclidly, it lbecomes imnlortant to discriminate between
them and those great. masses of limestonlle which.are sedimentary
deposits.
That these deposits of mineral matter, occupying fissures in the
stratified rocks, are not intrusive veins or dykes, blut, have been
formed by g'tduatl deposition or accretion, is shown by the banded
alrraingemelnt parallel to the walls, just noticed.  Further evidence
of this origiI is seen in the manner in lwhich the various minerals
surround or incrust each other.  Thus, small priisms ot apatite tare
enclosed in  large crystals of phlogopite, in spinel, and even in
massive apatite; crystals or crystalline  masses of calcite  are
imbedded in apatite and in quartz, and wvell-defined crystals of
hornblende (pal'gasite) occur imbedded inl others of plyroxene.  Inl
another example, small crystals of hornlblende are implanted oil a
largCe crystal or pyroxene, and  both of these are, in their turn,
incrusted l)y smaill prisims of epidote.  Th'lis latter crystal  v-was




14       TWENTY-FIRST REPORT ON THE STATE CABINET.           [58]
evidently from a drusy cavity, such as those often met with, representing  unfilled spaces in the midst of the veins, and lined with
large and well-defined prisms of apatite or of pyroxene.
While these associations evidently show a successive deposition
of the various mineral  species, another phenomenon, sometimes
observed  in vein-crystals, is presented by a prism  of yellow
idocrase from a veinstone of orthoclase and pyroxene in Grenville,
Quebec.  One extremity of the prism, which is about half an inch
in diameter, is imbedded in the matrix of the two minerals just
named, while the other, being broken across, shows that the
idocrase forms but a thin incrustingc shell, and is filled with a confused crystalline aggregrate of orthoclase, holding    a small priisim
of zircon.  This would show that a skeleton-crystal, such as is
sometimes seen in crystallizing solutions, had at first fornmed, and
was sLul)seqncntly filled up with the other minerals.  Similar cases
are well known to mineralogists; thus the crystals of zircon from
Laurelltian veins in St. Lavrence county, New York, are sometimes filled with calcareous spatl; and a granitic vein at Itaddam,
Connecticut, has afforded prisms of beryl filled with a mixture
of orthoclase and quartz holding minute crystals of garnet and
of tourmaline.  A strong confirmation of the view  that these
minerals have been deposited in their veins fiom soliution, is
afforded by certain phenomena not hitherto  explained, which
were, I believe, first noticed by the late Dr. Emmoons.  He observed that crystals of quartz imbedded in crystalline limestone,
ill Rossie, New York, have their angles so much rounded that
the prismaltic form  is almost or entirely eflhced, the surfaces
being smooth and shining.  This appearance, although not constant, is ob)served in many localities, and is not confined to quartz
alone —crystals of apatite and of carbonate of limle sometimes
exhil)iting  the same peculiarity.  At the same time as remarked
by Dr. Emmonos, the feldspar, scapolite, pyroxene, zircon and
sphene of these limestones present perfect forms, the crystals of
orthoclase, even in contact with the rounded crystals of quartz,
retaining their sharpness of outline.  Dr. Emmons considered the
rounded angles of these cyrstals to be due to a partial fusion,
though at the same time he did not overlook the fact that the
quartz, apatite and calcite were less fusible than those species
which, under similali circumstances, retained their crystalline foirms
intact (Geology of the First District of New York, pages 57, 58).
These observations have since been ablundantly confirmed in




59.]    LAURENTIAN LIMESTONES OF NORTH AMERICA.               15
Canada.  The crystals of apatite in Elmsley and Burgess, Ontario,
rarely present sharp or well-defined forms; but whether lining
drusy cavities, or imbedded in the calcareous veinstone, present
rounded or sub-cylindlrical crystalline masses, while the pyroxene
and sphene, which often accompany them, preserve the sharpness
of their angles.  The hypothesis which would explain by igneous
fusion this rounding of the alngles, is evidently untenable, first,
because the more fusible species show no signs of such action,
and, second, because the calbollnate of lime, which enicloses and
even penetrates the rounded quartz crystals, is not in any way
affected at the surfaces of contact as it would have been by fused
or half-fused quartz.  This rounding of the angles of certain crystals appears to me to be nothing more thanL a1 result of the solvelt
action of the heated watery solutions, from which the minerals
of these veins have been successively deposited, the crytals previously formed beinlg partially redissolved as a result of some
change in the temperature, or in the chemical constitution of the
solution.  Heated solutions of alkaline silicates, as shown by
Daubrbee, are without action on feldspars, as might be expected
from the fact, observed by him, of the production of crystals of
feldspar and of pyroxene in the midst of such solutions.  These
liquids would, however doubtless attack and dissolve phosphate
of lime, which is, in like manllner, decomposed by solutions of alkaline carbonates, and these latter at elevated temperatures attack
and dissolve crystallized quartz.
The regularity, and the frequently large dimensions of the
crystals, not less than their modes of association, and the other
phenomena just mentioned, serve to distinguish the minerals
of these veinstones from the same species which are found disseminated in the limestone beds.  In the latter case they sometimes occur in small distinct crystals, but more generally in
rounded irregular grains, which present a marked contrast to the
same minerals occuring in the veins.  This rounded form of the
minerals in the beds of limestone, is to be carefully distiilnguished
from  the rounding of the crystals in the veins just described,
although the two phenomena have hitherto been confounded by
those who have written upon the subject.  In the latter case the
rounding is bly no means constant, and is confined to a few species, while in the limestone beds it will be found that a rounded
form  characterizes alike apatite and quartz, and such silicates as
pyroxene, bornblende, serpentine and chondrodite.  The rounded




1 6      TWENTY-FIRST REPORT ON THE STATE CABINET.             [60]
shapes assumed b)y these minerals in limestone, and especially
by the silicates just mentioned, have been noticed by Naumann
alnd  Delesse, ao1110g others; anld the latter olbserver sulposed
that this condition might be due to a repulsive action between
the particles of the silicates and the suriroulding calcareous matter when both were in a plastic state under the influence of water
and heat.  The olbservations of Dawson and mnself, alld the
latter ones of Gtimbel, however, as detailed on pacges 43 and 44,
demonstrate that this rounded form, in mlany  cases, at least, is due
to no such subsequent action, but has been given by the calcareous
orga^nic structure, in whose chambbers these silicates were originally deposited.  It would, however, be premature to say that this
explanation is of universal apl)lication, but it may be affirmed in
general terms, that certain external forces have, in the limestone
beds, prevented the free deve opment which these mineral species
naturally assume while in the veinstones.  On the contrary, the
roundingl of the angles of certain crystals, to the exclusion of
others, is due to a partial dissolution of the previously formed
crystals.
As already remarked, it is impossible to draw any definite line
bettween the veins just described alld those already mentioned as
placed in the preceding class, and generally designated as granitic
veins.  Most of their characteristic mincrals lare common  to the
t(vo classes, and it is easy to trace a grladual change friom  the
typical grianitic veins, to those in which ctarbonate of lime is the
predonlinant mine~ral, and which are to the crystalline limestones
what the foirmer are to glneiss and mica-schist.  In both cases I
colnceive that they derive their mineral contenlts fr'om the adljacent
stralta, whose fissures they fill, and are entitled to the name of
segregated veins.  In both cases, also, it must be borne in mind
that other vacant spaces in the stiata, whether resulting from contraction, solution, or other causes, may prlesent contditions for
deposition similar to those of fissuriles, and may thus cgive rise to
drusy cavities, or to detached masses o;f crystalline minerals identical to those of the veinstonecs.  This view of the origin of g(ranitic
veins from  solution, and their distinction fromn intrtusive grlanites,
has been insisted upon Iby me in the Geology of Cnmada, pages
477, 644, and since, with  more details, in my Contributions to
Lithology in the Anmerican Jotrnal of Sceince [2]. xxxvii, 252.
To resume, then, it may be said that besides the fissures filled
-with igneous injected g1ranite, forminig what may be distinguished




[61 ]    LAURENTIAN LIMESTONES OF NORTH AMIERICA.              17
as granitic dykles, there are other fissures which have, by a slow
deposition fiom solutions, been filled with the constituent minel:rals
of granite, constititilln true granitic veinstones, which, unlike the
granitic dykes, -are often rich in foreign minerals.  These aggregates pass lby grradations into the pyroxenic and calcareous veinstones already noticed.  It is from  not knowing this distinction
that Durocher, Fournet and others have lelplexed themselves with
strange hyI)potheses in attempting   to explain the phenomena presented by the associations and juxtapositions of mineral species in
granitic veinstones, which they imagined to have been formed,
like granitic dykes, by the consolidation of a fused or pasty mass,
instead of being the result of a slow  deposition from  solution.
For convenience of definition, I have elsewhere distinguished these
veinstones by the title of endogenouts rocks, as describing the conditions of their formation.  The intrusive dykes, on the other
hand, I have called exotic, and the sedimentary strat~a, indigenotes
rocks.
As to the conditions under which these various minerals have
been crystallized, the beautiful researches of Sorby furnish lus
considerable light.  The limestones, fiom  Soinma, near Naples,
affrd, in a finely crystallized  state, the greater number of the
mineral species met with in the Laurentian limestones of North
America, and the crystals of hornblende, idocrase and orthoclase
firom  that locality contain small cavities, often of microscopic
dimensions, partially filled with water, holding ill solution alkaline chlorides, sulphates and carbonates.  As these cavities were
filled with liquid during  the formation of the crystal, the subsequent cooling has produced a partial vacuum; tlis is again filled
on heating the crystal to the temperature at which it was formed,
which in this way may lbe ap1l)roximately determined.  Mr. M orby
foulnd, by this method, that the horlblcndele, idocrase and feldspar
fromr the linmestones of Sommna must have been crystallized at from
360O to 380~ Centigrade, a temperature equal to that of low redness.  The crystals from the granitic veins of Cornwall, including
(quartz, mica, orthoclase and oxyd of til, all of which contain cavities holding watery solutions, have shown, il like manner, to Mr.
Sorby, that these minerals -must have been deposited at temperatu res al)proachillg those deduced for the minerals firom the crystalline limestones of Somma, or from 2000 to 340Q Centigrlade (from
392~ to 644Q Fahrenheit) (Quar. Jour. Geol. Soc., London, xiv,
453).  He thence concludes that these minerals have crystallized




18       TWENTY-FIRST REPORT ON THE STATE CABINET.          [62]
at temperatures in some cases equal to that of low redness, under a
pressure equal to that of several thousand feet of rock, and in the
presence of water holding in solution a large amount of alkaline
salts, which can in some instances be dletected in the liquid from
these cavities.
These conclusions are supported by the experiments of Daubraee,
who succeeded in forming crystallized pyroxelie, feldspar and
quartz, in the presence of alkaline solutions at a low red heat.
De Senarnmont also obtained crystallized fluor-spar, sulphate of
barytes and quartz, in the presence of water, at temperatures
between 2000 and 3000 Centigrade.  The deposits from the thermal waters of Plombietres, however, show  that some hydrous
silicates, like apophyllite, harmotome and chabazite, may be crystallized at temperatures below that of boiling water, and there
are reasons for believing that quartz may also be crystallized at
low temperatures.  Thus, while the observations of Sorby show
the temperatures at which certain minerals have been crystallized,
it does not necessarily follow that some of these crystals may not
be generated at lower degrees of heat, which, for the minerals
found in nature, must, in each case, be determined by experiments
like those of Mr. Sorby.
It will be readily understood that the conclusions as to the conditions of temperature under which certain minerals have been
crystallized, apply with equal force to those fieely deposited in
fissures or cavities of the sedimentary rocks, and those which may
have cyrstallized in the midst of the deeply buried sediments
themselves; since these mlust have been permeated with the same
solutions which circulated in the fissures, adcl which, in fact, derived
from the beds their dissolved mineral matters.  The solvent power
of waters holding alkaline carbonates and silicates, and heated to
300Q or 3600 Centigrade, is probably very great.  The questions
of the generation of many of these silicates, and of the original
composition of the sedimentary rocks, will be discussed further onl.
Those who have written on crystalline limestones, and on their
mineralogy, have, for the most part, neglected the distinction
between the rock and its veins; thus Delesse in his elaboralte
memoir on the minerals of crystalline limestones, does not even
allude to it. Incidentally, however, several observers have noticed
the occurrence of various crystallized minerals in veins amongoD( the
Laurelltian limestones of New York and New Jersey. First among
these may be mentioned Prof. Charles Upham Shepalrdl, who, in




[63]      LAURENTIAN LIMESTONES OF NORTH AMERICA.             19
1832, published a description of the minerals of Orange county,
New York (Amer. Jour. Sciece [1], xxi, 321). Pirof. H. D. Rogers
also, ill his Final Report on the Geology of New Jersey, notices
the occurrence of aggregates of carbonate of lime, with feldspar,
hornblende, pyroxene, sphene, spinel, etc., forming dykes or veins
in the crystalline limestone of that region; and shows, moreover,
that the franklinite and red zinc ore, with their associated minerals,
occur in calcareous veins.  Finally, Mr. W. P. Blake, in describing a locality of the first mentioned grolup of minerals in Vernon,
New Jersey, declares it to have the characters of a segregated
vein (Anmer. Joumi. Science [2], xiii, 116).  Despite these observations, however, Emmons and Mather did not regard the distinction
whiclh evidently exists between the bedded limestones and the
veins, many of which, from a predominiance of c-arbonate of lime
in their composition, became confounded in their eyes with the
limestones themselves, leadinlg both of these observers, as we
have already seen, to admit the existence of eruptive limestones;
while Emmons even concluded that all the limestones of the
northern Laurentian district of New York were non-stratified, and
of eruptive olrigill.  A careful geognostic study will, however, we
think, suffice to show that by far the greater part of the calcareous
rocks in the Laurentian system of North America are stratified,
and that the so-called eruptive limestones are really calcareous
veinstones, or endolcenous  rocks, generally including foreign
minerals, such as pyroxene, scapolite, orthoclase, quartz, etc.
These, in other veins, predominate to the exclusion of carbonate
of lime, and then present agglregates approaching in composition
to the granitic veinstones, into which they pass by the exclusion
of calcareous and magonesian minerals, such as calcite, apatite,
pyroxene, mi.agnesian mica. scapolite, etc.  These species serve to
distinguish the veins of the limestone groups from  the proper
grlanitic veinstones, in which latter, orthoclase, albite, quartz and
nuscovite are the characteristic minerals.
The so-called Primitive Gneiss formation of Scandinavia has
long, been regarded by the Geological Survey as belonging to the
Laurentian system  (Esquisse Geologiq.ue du Canada, p. 17  Geology of Canada, p. 586), and is associated with crystalline limestones, which have afforded most of the minerals that are to be
met with in the Laurentian limestones of North America, together
with many additional species.  Such of these minerals as are common to the two regions, offer close r,!scmblanccs, not only il their




20       TWENTY-FIRST REPORT ON TIIE STATE CABINET.          [64]
characters and associations, but also in the mode of their occurrence.  These resemblances were in fthct noticed so longt ago as
1827 by Dr. William  Meade (Ame'. Jour. Science [1], xii, 303),
who called attention to the great similarity between many Scandinavian minerals, particularly fiom  the vicinity of Arendal, and
those found in Orange county, New York, and in Sussex county,
New Jersey.  He instanced, among others, the species pyroxene,
chondrodite, scapolite, garnet, sphene and ilmenite.  DaLubree,
wrho in 1843 published an instructive account of his examination
of the metalliferous deposits of Norwa,,y and Sweden, furnislles
some interesting details of the minerals associated with the beds
of magnetic iron ore in the vicinity of Arendal (Ann. des Ailines
[4], iv, PP. 199, 282).  The ore is here found, sometimes in gneiss,
andl at other times in a gneissoid rock, consisting of various admixtures of pyroxene, horlblende, garliet, epidote and mica, the whole
associated  with crystalline limestones.  These strata are cut by
numerous well defined but irregular veins, which are described
by Daubrhee as granitic or syenitic in character, and have yielded
the following minerals'   Orthoclase,  scapolite, quartz, apatite,
lamellar carbonate of lime, hornblende, black mica in large plaltes,
garnet, epidote, allanite, gadolinite, axinite. zircon, sphene, spinel,
slpecullar iron, and more rarely, beryl and  leucite.  Serpentine,
chondrodite, lievrite and corucundum  are also enumerzlated among
the minerals of the district, though not especially mentioned by
Daulbr ee as occurring in the veins.  In addition to the species
already mentioned, these veins contain datholite and apophyllite,
with analcime and varioius other zeolites, which are, however, l)ossibly of later origin than the other minerals.  These veins sometimes include irregular friagments of' the wall-rock,  and present
cavities lined with crystals, showing, not less clearly than the
veins which we have mentioned in the Laurenitialn rocks of Caniada,
that they have been formed Iby the progressive filling u p of fissures
in the strata.
In some instances, these veinstones, by the absence of calcareous
and miagnesian minerals, become granite.like airreoates of orthoclase and quartz.  Daiubr6e, however, havingy reference to their
structure, calls all of these veins glranitic, though they sometimes
contain lamellar carbonate of lime.  He agrees with Scheerer in
supposing them  to have been filled by segregation or secretion
from. the surroundilg strata, while Durocher, on the contrarTy, rejected this view, and supposed them to have been filled bly injection.




[65]       LAURENTIAN LIMIESTONES OF NORTH A-MERICA.             21
These veins are seldom of great extent, and near Stockholm, where
they are very a)bundallnt, rarely exceed 300 feet in length.
At the iron mlines in the island of Utoe, where the ore is a mixture of magnetic and specular oxyds, occurring in beds, with hornblendic rocks passing into gneiss, or with crystalline limestone
holding hornblende and mic., granitoid veinstones, like those of
Areindal, arec met with, holdingi orthoclase and quartz, with toutrmaline and oxyd of till, together with the rare minerals, pet.litc,
spodumene and lepidolite, which occupy the cent'ral portion of the
vei ns.  This association is the more worthy of notice, as the only
other knownll locality of the rare mineral petalite (if we except the
castor of Ell)a) is in the crystalline limestone of Bolton, Malissachusetts, where it occurs with scapolite, hornblende, pyroxene,
chrysolite, spinel, apatite and sphence-the char(acteristic minerals
of similar limestones ill Canada, New York and Scandinavia.
The occurrence of oxyd of tin ill the above associations is not
without interest in relation to the economic nminer.aloyr  of the
LauellntiLn system, to which the rocks of Utc(  probably Ibelong;
and it is well to recall, in this connection, the existence of till ore
ill rocks, probably of the same age, at Pitkaranta, on Lake Ladogni
in Finland.  A. rock consisting of gcreenish lamellar hornllenlde,
Awith  arlnet, epidote and pyroxcne, is there interstratified with
mica-slates, sometimes graphitic, and -with a grilanitic gneiss, the
series being cut by granite-like veins.  In certain )beds of the horn-'11
b)lendic rock, magnetic irion is disseminalted to such an1 extent thart
the mass becomes an iron ore.  This is occasionally associated
with oxyd of tin, which in some parts predominaltes, so that tllhe
ore is mined for this metal.  Other horuiblendllic  eds in the series
are rich in copper pyrites, which is also disseminated in the micaslates, and is sometimes accompanied by sulphurets of lead, zinc
anlld mlolybdenullll  (DaUocter, Annl. les Iinles 8 [4], xv, 316).  These
associations should not be overlooked in the study of ou1r Laurentian rocks, whiclh may yet be foiund to be tin-bearinlg.
Another mineral  which may possibly be met with in the Laurentiall rocks of Canada is gold, since small quantities of the precious metal are found in several localities in Sc:lndinlavia, some of
them  prol)bally, as that of 43arbo, near Arendtal, in rocks of LtLureltian aTge.  The  cold of Scandinavia is, however, ill such smiall
quantities as to be nowhere malde the olbject of milinetg.  Details
with re~gamd to it are given by Daubl)rle  (ilb. des Mi31nles [4], iv,
265) and by Durocher (Ibid. [4], xv, 371).  Smalll quantities of




22       TWENTY-FIRST REPORT ON THE STATE CABINET.              [66]
mercury, in the forms of cinnabar and silver-amLalgam, are also
found associated with galenal at Sala ill Sweden, in crystalline
limestones, plrobal ly Laurentian.  The notion that gold belongs
onlly to rocks of Lower Silurian age, was many years since disproved by its discovery in the Upper Silurian slates of Eastern
Canada, and more recently it has been shown that the gtreat gold
mines of California are in strata far more recent, and chiefly of
the Jurassic and Triassic periods.
[Since the writiong of this report, native gold has been found in
the county of Hastinlgs, under several conditions; first, associated
with argentiferous fiahlerz and with inispickel inll mall veins of
bitter-spar, calcite and quartz cutting nmitgnesian limestones, in
Madoc; second, in a quartz vein in Marmora; and thirdly, in
small irregular veins cutti  ng magnesian limestone, with ferrifelrous
bitter-spar, black hornblende, quartz and a black cotaly nlatter, i
which, as well as in the bitter-splar, the gold is disseminated in
plaltes scand crystalline scales.  This last locality is also in Madoc,
Ontario.  See the Rel)ort of T. Sterry Hunt and( A. Michel on
gold in the county of Hastilgs, 1867.]
The existence of the Laurentian system in Bavaria and Bohemia,
as already stated, has lately been established by Giiunbel, l)oth by
stra.tilraphical and palahontological evidence.  He finds in Bavaria
an ancient gleissic series, estimated as Inot less than 90,000 feet in
tlhickness, and by him divided into a lower portion, chiefly of red
or variegated gcneiss, which he calls the Bojian gieiss, and -1an
ul)per p)ortion, distingcuished as tile Heicynian gneiss.  To this
succeedls a series coniisitinl.cchiefly of micaceous schists, with hornblendic.and chloritic bands, overlaid by what lie calls the Hercynian clay-slate formation, which immediately underlies the plrimordial zone of the Lower Silurian system.  The prevailing character
of the Hercynian gneiss is greyish, elry quartzose, oftenl containlin(r
black iagllesian mica, alid frequently having a1n admixture of oligoclase.  Great portions of this gneiss are also nlarked by the
presellce of iolite or dichroite, givinlg rise to a distinct variety of
rock, the so-called iolite-gieiss or diclroite-gneiss.  Beds of hornblende slate, diorite and hornillendic gneiss are also abundant in
this series, particularly in the vicinity of tile limestone bands,
and are often acconjmp)anied by b)eds of metallic sulphlurels, and by
lenticular masses and beds of gra phite, which somel imes inlpiegnates tile beds to such all extent as to le xvrougllt with prlofit.  It
is in these strata that tht e well-k~nown  plumli(yago deposits of the




[67]       LAURENTIAN LIMESTONES       OF NORTII AMERICA.          23
vicinity of Passan are found, under conditions closely similar to
those of Canada and New  York, ill the same geological system.
The crystalline limestone band near Passalu, which OCC1rs in hornblendic gineiss, is from  fiftyv to seventy feet in thickness, aind is
directly overlaid by a bed of several feet of hornblende slate,
between which and the limestone, a bed of three or four feet of
serpentine is interposed, and in other parts a layer of nearly compact scapolite, mingled with hornblende and chlorite.  The stratified cgranular limestone beneath contains, amonlg other mlinerals,
serpentine, chondrodite, hornblende, mica, scapolite, garnet and
graphite; the disseminated serpentine here, as in Canada, replacing the Eozoon Caiadeiise.
The occurrence of iolite, as a frequent element in the Laurlentian
gneiss of Bavaria, is a fact of interest, inasmuch as it is also one
of the minerals of the sfame ancient gneiss in Scandinavia, and may
}be looked for in this country, although it has not yet been detected
in the undoubted Laurentian rocks of North America.*
The Hercynian clay-slate series of Bavaria, already referred to,
and supposed by Giunlbel to correspond to our Huronian series,
includes a formation of crystalline limestones more than 300 feet
in' thickness, containing, like the older limestone of the Lkaurentian system, graphite, chondroditc, hollrnblende and serpentine, the
latter two minerals repllacing a peculiar and distinct species of
Eozoon, named Eozoon Bavar'icum.
Allusion has been made to the crystalline  limestones which
occur in Bolton and the adjoining towns ill Eastern Massachusetts,
and resemble in geognostic alld mineralogical characters those
of the Lanrentian system.  There are, however, not wanting   reasons for. supposing them  to belong to a more recellt geologic
period, alnd the fitcts recently observed in Bavaria, and detailed
above, show what was antecedently prolbable, that similar llilleraloogical characteristics may be found in crystalline limestonaes of
very different ages.
Inl this connection, it is not without interest to recall the mineral
characters of the rocks of Ceylon, which l)lresellt many striking
resemblances to the Laurentialn strata of North Alncrica, and may
perhaps be found to belong to the same system.  The islalnd was,
* Iolite, as I have elsewhere remarked, is related to the feldspars, of which it has the
atomic;olume, and may be looked upon, chemically, as a feldspar, with the oxygen ratios,
5: 3:1 (intermediate between labradorite and anorthite, and corresponding to barsowite
and bytownite), in which magnesia, sometimes with protoxide of iron takes the place of
lime and soda.




241        TWENTY-FIRST REPORT ON 1IHE STATE CABINET.    [68]
so long ago as 1818, described by Dr. John Davy (Trans. Geol.
Soc., London, 1st series, v. 311) as made up of old feldspathic
gneiss and gneissocl limestone, together with granular crystalline
limestone and dcolmite, both in mountain masses and in veins, the
latter sometimes white and lamellar, and enclosing spincl and apatite, priisms of yellow  mica, cinnamilon-stone g'arnet, yellow  tourmaline and zircon, the latter two minerals associated with feldspar
and quartz.  The lameliar glraphite, so abundallt in the island, was
regarded by Dr. Davy as the chlaracteristic associate of the gems,
spinel, zircon, garnet. etc. Anhydrite exists there in the gneissoid
limestone, which he found to be impregnated also with sulph~ate
of magnesia, nitre and nitrate of lime.  In addition to these minerals may be mentioned sapphire and chondrodite, which are found
tooether, imbedded in lamellar calcite, in Ceylon, and were mentioned by me ill the Report oz the Geology of C(eazrtda for 1847,
page 134, as similar to those of our Laurentian rocks.
It is 1now proposed to consider the minerals of the limestones,
with their accompanying be(ls of pyroxeenite, gneiss, etc., which
together constitute  what we have denominated  the limestone
gr'oups of the Laurenltinll system.  When the mineral species occur
disseminated in the stratified  or indigenous rocks, and form an
integral part of them, they will b)e designated as bed mineralcs, blut
when, on the contra-ry, they  appear to belong to eidogenoius
masses, occupying fissures or cavities in the strata, they will be
spoken of as vein-minerals. The study of the species found under
these two conditions will show that nearly al1 the minerals met with
in the veins likewise occur disseminated in the strata, and will permit the inference that it is from  the latter that the vein-minerals
have all been derived.  Il the case of such as contain the rarer
elements, however, it may well be supposed that these are so Uiffused through the mass of the sediments, that it was only when
co(ncentrated in the veinstones that they are caplable of beino
recotlgnized I)y minleralogical ch-aractelrs.  It is nevertheless evident
that, in certain catses at least, the particles of the seclimelntary
strata have at one time possessed a sufficient moblility to peirmit of
crystallization, and of a partial segregation andl grouping of their
heterooleneolus elements.
In the following list are included all the minerals, so frm as yet
known, which may be regarded as belonging to the Lauirentian
limestones of Norlth America, and their immediately related strata.
In addition to the rocks of this denomination it COanada, and in




[69]     LAURENTIAN LIMESTONES OF NORTH AIERICA.            25
northern New York, are to be added those of the Highlands of
the Hudson, and their extension in Orange county, New York, and
in Sussex county, New Jersey.  The observations of Prof. J. Hall
and Sir William Logan upon these rocks in the Highlands, have
confirmed the views of those who had previously asserted them to
be older than the Lower Silurian series, and shown that they are
doubtless of Laurentian age. This more southern area is much
better known and explored than the comparatively wild and uncultivated Laurentian region of Canada, yet with the exception of the
remarkable zinciferous minerals, f'ranklin!ite, red zinc ore, willemite and dysluite, which are confined to a small section in New
Jersey, nearly all the mineral species of these limestones found in
the United States have already been recognized in Canada.
MIINERALS OF THE LAURENTIAN LIMESTONES OF NORTH AMERICA.
Calcite.                       Epidote.
Dolomite.                      Allanite.
Fluor-spar.                    Zircon.
Heavy-spar.                    Spinel.
Apatite.                       V6lknerite.
Serpentine.                    Corundum.
Chrysolite.                    Quartz.
Chondrodite.                   Sphene.
Tephroite.                     Warwickite.
Wil lemite.                    Ilmellite.
NWol I lastonite.              Ruti le.
Hornblende.                    Magnetite.
Pyroxene.                      Hematite.
Babingtonite.                  Franklinite.
Pyral lolite,                  Zincite.
Talc.                          Culbic pyrites.
Gieseckite.                    Magnetic pyrites.
Loganite.                      Copper pyrites.
Scapolite.                    AMispickle.
Orthoclase.                    Fahlerz.
Oligoclase.                    Bismuthine.
Phlogopite.                    Blende.
Mar garite.                    Antimony glance.
Clintonite.                    Molybdenite.
Tourmaline.                    Gold.
Garnet.                        Graphite.
Idocrase.                      Anthracite.
4




26       TWENTY-FIRST REPORT ON THE STATE CABINET.    [70]
No one bled or vein probably has ever been found to include all
the mineral species of the above list, yet the composition of some
of these veinstones is nevertheless very complex, as ma.y be seen
bly the following examples.  The first is fiom my own observation
of the vein on the tenth lot of the fifth range of Grenville, Ontario,
which cuts a crystalline limestone hboldling scales of mica and
graphite, and has itself been mined as a source of the latter mineral.  The minerals found in this vein are calcite, apatite, serpentine,
wollastonite, pyroxene, scapolite, orthoclase, oligoclase,  garnlet,
idocrase, zircon, quartz, sphene and graphite-foulteecn species in
all.  A still larger number has been observed by Mr1. W. P. Blake
in a singlle vein, traversing crystalline  limestone, in Vernllon,
Sussex county, New Jersey.  He there found calcite, fluor-spar,
chondroclite, horllblende, phlogopite, mnargarite, red spinel, red
corullndum, zircon, sphene, rutile, ilmenite, pyrites and gralphite, to
which list he adds " hydrous peroxyd of iron, and hydrous silicates
of alumina" (Amer. Jotur. Science [2], xiii. 116).
These veinstones, as will be seen from numerous examples in the
following  pages, are found traversing alike the limestones and
their various associated strata.  In an instructive instance in the
Cheever ore-bed at Port Henry, Newv York, a vein is found in a
b)ed of magnetic iron, of which it includes angular fragmcnlts.
The veinstone, fir specimens of which I am  indebted to Prof.
IIall, consists of cleavable masses of a greenish triclinic feldspalr,
l)yramidatl crystals of quartz with rounded ang(les, octahedrolns
of ni:ioanetite, a substance resembling allanite, with  a  specific
gravity of 4.09, and a dark green mineral with the cleavage of
pyroxen, but having the hallrdness and specific graviity (2.713)
of locganite.  All of the elements of this remarkable aggroregate
with the exception of the magnetite. are in masses of an inch or
more in diameter.
CALCITE. -In many of the veins traversingl  the strata of the limestone group, calcite is entirely  wanlltillng, or is present only in small
portiolns; but in others it occurs in large quantity, and so far l)redominates that the veinstone is readily mistaken for a crystalline
lincestone, generally coarse, bat sometimes very fine grained, which
is occasionally white, but more frequently yellowish, pink, flesh or
salmon colored, and rarely p.ale blue.  These ancient calcareous
veinstones are sometimes nearly free ffrom  foreign minerials, but
llore frequently include crystals, often of large dimensions, of




[7 1]     LAURENTIAN LIMESTONES OF NORTH AMERICA.              27
apatite, magnesian mica, pyroxene, brown tourmaline, and other
ninerals.  Drusy cavities, in the veins of mingled calcite and
apatite in Burcgess, are sometimes lined with large crystals of dogtooth spar.  We have already insisted oil page 48 upon the fitct,
which is there for the first time pointed out, that it is these highly
calcareous veinstones which have given rise, in North America at
least, to the widely-spread notion of the eruptive origiu of crystalline limestones.
Of calcite as a bed-mineral, constituting great stratified m.asses
of limestone in the Laurentian series, it is not necessary here to
speak.  It is, however, to be relllarked that in these limestones,
as in those of later periods, we have now evidence that portions
of the carl)onate of lime once belonged to living orglanisms, as is
shown in the calcareous skeletons of the Eozoon.  These, though
sometimes preserved bly injection with silicates, appear in other
cases with their tubes and canals filled with carbonate of lime,
evidently-like the silicates-a chemical deposit, and there is no
dloubt that a part of these limestones, like those of more recent
formations, have been directly precipitated by chemical reactions
from the waters of the ocean.  The often repeated assertion that
organic life has built up all the great limestone formations, is based
upoll a fillacy, for animals have no power to generate carbonate
of lime. Although many invertel)rate animals construct calcareous
skeletons, which form a great part of the limestone of the earth's
crlust, the pre existence of this carblonate of lime is one of the
conditiolls necessary to their growth, and, as I have elsewhere
shown, owes its oriegin to chemical reactions which are still going
on in the ocea:n's waters, and which have in past times given rise
directly to limestone strata, in which the oe(urlrence of shells and
corals is only accidental (Geol. CJan., pages 575, 631).
DOLOMxTE.-As already pointed out inll the Geology of Canada,
pages 24 a1md 592, large 1eds of the Laurentian limestones are
mnagnesilan, and sometiles have the composition of true dolomites.
These dolomlites and magnesian limestones have been found to contain serpentine, hornblende (tremnolite), apatite. quartz and small
portions of mica, and they may, perhaps, in different localities,
include all those mineral species which have been indicated as
belonging to the limestone striata.  It is to be remarked that the
calcareous skeleton of E ozoon Canadense, which is carbonate of
lime, is found, in specimens from  Burgess, replaced by dolomite.




28       TWENTY-FIRST REPORT ON THE STATE CABINET.           [72]
k'he mineral filling the chaml)ers of the fossil is ill this case
loanlite, but the delicate tubuli, which are preserved in the
Eozoon fiom most other localities, have almost entirely disappeared; a fact perhaps connected with the removal of the calcareous skeleton, and its replacement by dolomite.
As a vein-mineral, dolomite has bleen but seldom observed in
the Laurentian veins.  A mnancesian carbonate of lime is, however,
found in two localities in North Burgess, in one case forming the
g.angue of apatite crystals, and in the other of prisms of bro-wn
mica. The analysis of the yellowish splarry carbonate, in the latter
instance, showed it to contain, besides carbonates of lime and magnesia, a notable amount of carbonate of iron and a little carbonate
of manganese.  These complex carbonates require further study.
The interesting results obtained by Jenzsch inl the analysis of a
similar white sparry carbonate, which, at Sparta, New Jersey,
forms the veinstone of the red zinc ore and frianklinite, deserve
to be recalled in this connection.  He found the spar to contain
carbonate of litme 79.96, carbonate of magnesia 1.94, carbonate of
manganese 11.09, carbonate of iron 0.60, carbonate of zinc 0.58,
besides 5.39 per cent. of flulorid of calcium, an ingredient which he
has also detected ill the calcareous spar of several other localities
(Amer. Jour. Science [2], xxi, 197).
FLuoR SPAR.-Inasmruch as fluorid of calcium enters into the
composition both of the calcite and the apatite of these calcareous
veins, we are prepared to find it separately crystallized, as fluorspar, which occurs in several localities amonog the Laurentian
limestones of the United States, in veins with scapolite, chondrodite, pyroxene, spinel, and other characteristic species.  In Canada
it is met with in Ross, Ontario, in small purple cleavable grains,
imbedded, with prisms of apatite and large crystals of spinel, in
what has been described in the Geology of Canacda, pages 461
and 463, as a yellowish white crystalline limestone, and which,
from its mineralogical characters, will probably be found to be a
veinstone.  In addlition to this, a small vein, filled with cleavable
purple fluor-spar, was observed in the vicinity.  The purple fluor
which occurs with red heavy-spar, in fissures or cavities in the
limestone associated with the hematite of Iron Island, in Lake
Nipissing (Geol. Can., pages 456 and 463), is priobably also a veinstone mineral, and I know as yet of no certain evidence that fluor
occurs as a distinct species amongic, the Laurentian bed-minerals.




[73]     LAURENTIAN LIMESTONES OF NORTH AMERICA.                 29
HEAVY-SPAR. —The heavy-spar found in the Laurentian rocks,
cgenerally belongs to the recent or lead-bearillng veins, but sometirnes alppeas in the older veirs. In addition to that just mentioned
as occurrino at Iron Island, small quantities of flesh-red lainellar
sulphate of barytes are foulld iwith quartz, impllantcd on apatite,
in a vein in Bur gess.
APATITE.-This is one of the most ablundant minerals in the
Laurentian veinistones, of which it sometimes constitutes the entire
nmass, appearing, as descrilbed on pige (761 of the Geology, as a
crystalline, honlogenleous rock, translucent, with an uneven firacture, a vitreous lustre, and a grayish color, passing into glreenisi
or reddish.  It then resembles in its aspect some varieties of
quartzite, and at other times consists of incoherent grains, resenimlbling, a disintegrating  sandstone.  Another variety is more coarsely
crystalline, sea-green in color, and, like the last, intermixed with
a1 little black mica.  In this instance, large and distinct prisms of
apatite, with rounded angles, are ol)served penetrating the confusedly crystalline mass of the same mineral, which has apparently
been deposited upon and around them.  The locality of this variety
is on the twenty-fifth lot of the eighth range of North Elmsley,
Ontario (which is described in the Geology as a bed, but is proba)bly a vein).  There, adjoillilng three feet of nearly pure apcatitc,
is found an admixture of crystals of apatite with crystallile fleshcolored carbonate of lime, accompanlied by loganite and sphene.
In several other localities in this region, outcrops of a  )precisely
similar aggregate are found, which would lie described as crystalline limestones, generally reddish or pink in color,,land including,
crystals and irregular crysttalline masses of green apatite, soimetimes
associated with large priisms of magnesianl mica.  In those 1)laces
where it has been  possible to determine the attitude of these
aroireoates, it is very evident that they are true veinstones, cutting
the bedded rocks of the country. Crystals of aIlatite several inches
in diameter are often met with, and one in the Museum  of' the
Geological Survey is eighteen inches long and tnenty-six inches
in circumference, and weighs about one hunldred pounds.  Like
all the apatite crystals from this region, its lateral and terminal
angles are very milch rounded.  The apatite crystals of these
veinstones are generally of some shade of green; but in Ross,
crystals of a reddish-brown color are met with, and others of an




30        TWEN'TY-FIRST REPORT ON THE STATE CABINET.           [74]
olivegreeccn, passincg into wax-yellow, inmeldded with purple fluor,
ill carl)onate of lime.
Tlhe crystals of apatite from these veillst(ones sometimes include
rounded crystals of quartz, or of carbolllte of lime, and on the
colltrary are sometimes themselves imbl)e(ded, not only in carl'bonate of lime and dolomite, but in massive alpatite, in quartz, in
nica, or iron pyrites, in foliated  grapliite, and prolably in other
minerals.  In one case, a crystal of aptatite one-fourth of an inch
in diameter and two inches long, was founlld imbedded in a large
crystal of mica, one end only projecting from  the side of the
mica pi-ism, with which the prism of apatite was at iight angles.
In Ross, cirystalline grains of yellow apatite are inmbedded in octahedrons of black spinel.  As already stated, prisms of apatite,
often of large dimensions, line drusy cavities in the veils of
massive apatite, or of minlgled apatite and pyroxene.  In the
latter case, large crystals of the two species iare sometimes foiund
gr-ouped together like those from  Snaitum,, in Norway.  In the
specimens from  the latter locality, however, unlike those fiom
Burgess, the apatite  prisms prieserive their sharpness of outline,
and, as well as the accompanying pyroxene, are pairtially incrusted
-with quartz crystals.
Apatite occurs iln the veins in Burgcess incrusted with crystals
of quartz, sometimes, smoky, felrulgirt)s, or amnethystille, and at
Ticondeleoga, New  York, crysta:ls of aplatite are imb)edded   in
massive vitreous quarltz.  The ra ldiated and botryoidal apatite,
named eupyrchroite by Emrmoils, is worthy of notice as a peculi.r,irm- of the mineral; it occurs with qualrtz, 1l'O1wn toullmalille and
allanite, filling a vein at Ticonderoga.  The minieral from  North
Burgcss, as showvn in the Geology of Canada, belongs to the
variety fluor-apatite, the analysis of a pure massive specimen havinag given me phosphate of lime 91.20, fluorid of calcium  7.60,
chlorid of calcium 0.78, insoluble 0.90   1]00.48.
Ap.atite as a bed-mineral is very frequent, bIoth in the limestones
of the Laurentian systenm and their associated iocks.  Small crystals of it are often disseminated through the limestone beds, generally in very small prolportion, lbut in sonimc cases rising to two
or three per cent, or evenl a much larger amounltlll, thougrh still
in the form  of grains or small crystals, often with pyroxene.
These larger proportions of apatite appear to chariacter-ize certaini
beds or )andls in the limestone.
Apatite also occurs disseminated in grains or small masses,




[75]       LAURENTIAN LIM;ESTONES OF NORTII AMERICA.               31
nlalkillg the stratification in the beds of the pyroxenite, and il
one instance, to be descrilbed further on, was  otlserved formingl   a
small interrupted bled in this rock.  The magnetic iron ore, which
often forms beds in the immediate vicinity of the limestones of the
Laurentian series, and, like the pyroxcnite, is to be regardled ias
b)elonging( to the limestone groups, contains in some places in Newv
York, a la,-ge admixture of grains or small prisms of apatite, generally reddish-brown, but sometimes colorless, and occasionally
associated with grains of green pyroxene.  Specimens of a similar
aglgregate of magnetite and apatite are said to have beiie foulnd on
the Ottawa; and it is worthy of remark that the extensive beds
of iron ore found in Laulrentian rocks in Graiingjilrde ill Sweden,
and consisting of an admixture of matgnetic and specular oxyls,
very generally contain grainsll  of atpatite, whose presence is sI,)pposed to depreciate the quality of the iron there mallllfactured.
(Dterocher, Ann. des Mines [4], xv, 249).
SERPENTINE. —This species, thoghl  not very common ill the
Laurentian veinstones in Canada. sometimes occurs in smiall disseminated grains, or in crystals of considera!)le size, imbedded in
calcite.  Examples of this occur in North Bui-rgess, where, in one
locality, imperfectly defined crystals, an inch in diameter, alld in
another, smallll riains,  with corundum, sphene, mica and 1)roxene,
are found; in both cases imbedcled in calcite.  A massive serpentine also occurs, forming the  angute of large crystals of mica in
northern New York.  The large crystals of serpentine (sometimes
enclosingi  a nucleus of chllrysolite) fiom Snaruim in Norwlay, which,
according to Scheerer, are accompanied wit  mica,.and imbeded in
ilmcnite, or in magnesite, in the midst of gneiss, prol)al)ly belong
to a vein.  Crystals resembling them  occur in New York (Amer.
Jour~. Science [2], xvi.)
Distinct from these veins are the small seams filled with fibrous
serpentine or chrysotile, which are frequently found traversincg the
massive serpentines, or the mixtures of serpenltine anid limestone
whichl make up great beds in the Laurentianll series.  Maissive
translucent serpentine often occurs as the millelral replacilg the
Eozoon (actnatdense, the canals of which  are in such cases injected
with this silicate.  In some cases the unbroken calctareous skeleton of the fossil is preserved in the serpentine, whlile in others,
olnly broken anld detached fragments of the skeleton are founcd,
sp1 arsely distlrib ted through the serpentine.  The presence of dis



32        TWENTY-FIRST REPORT ON THE STATE CABINET.           [76]
seminated gTrains of serpenltine, in glreater or less al)undance,
characterizes beds, 1)oth of pure limestonel anld of dlolotmite, ill thle
Laurentian series; and beds of pure, or nearly pure, seCrpentinle
are also met with, sometimes enclosingl  scales of mica, grains of
calcite, which, under the microscope, are seen to be fraiments
of Eozoon, or finely disseminated peroxyd of iron, which gives to
the serpentine a deep red color.  Concretionary masses of serpentine, sometimes exhibiting iii the arranoement of different colors.a banded or agatized structure, are often met with, imbedded in
the limestones, and generally have a nucleus of white gratnul ar
pyroxene.  These masses may vary from a few inches to a foot or
more inl diameter,.
I have already elsewhere described the composition of the Lanrentian serpentines, their low specific gravity and pale colors —
characters which are due to the small amount of oxyd of iron,. and1
the large proportion of water (equal to about fifteen per cent)
which enters into their composition.  These characters, together
with that of the constant absence from them of chrome and nickel,
serve to distinguish the Laurentian serpentines of North America
from most others known, and to connect them with those from the
old( rocks of Scandinavia, with which they have a close resemblance.
An analysis of the chrysotile from a narrow vein traversing the
Eozoon rock of Petite Nation seigniory, Quebec, gave me, silica,
43.65; magnesia, 41.57; protoxyd of iron, 1.46; water, 13.48=
100.16.
CIIRYSOLITE. —This species, which  is found in the crystalline
limestones of Somina, and, according to Rose, occurs wvith the
serpentines of Snarum, is known in the crystalline limestones of
Bolton, Massachusetts, under the name of boltonite, which Messrs.
Lawrence Smith and Brulsh have shown to be a pure magnesiachrysolite.  I place it in the list of Laurentianll minerals, on the
authority of Messrs. Horton and Beck, according to whom, boltonite occurs in several localities in limestone, associated with
spinel and horinblende, ill Oralnge county, New  York (Beck,
Mineralogy of lVew York, page 283).  It is not improbable that
this mineral may be more widely diffused, and it has perhaps been
confounded with chondrodite, like whic'h species, and like serpentine, it will probably occur both in beds and in veinstones.
CHONDRODITE. —This flLuosilicate of macgnesia occurs in calcareous
veins, generally with spinel, in numerous localities in the United




[77]      LAURENTIAN LIMESTONES OF NORTH AMERICA.             33
States, but I have as yet noticed it in Canada only in beds, where
disseminated grains of chondrodite mark the places of stratification in the limestone.  In one instance, in a specimen of limestone
from an unknown locality, the contact of two layers, one marked
l)y grains of chondrodite, and the other by grains of serpentine, is
distinctly seen.  A similar.association of the two minerals occurs
at St. J6r6me, in the province of Quebec.
TEPHROITE, WILLEMITE.-These two rare species, the first a
silicate of manganese, and the second a silicate of zinc, both of
them having the general formiula of chrysolite, with which the
fiIrmer is isomlorphous, have hitherto only been observed il North
America, in Lalurentian veins, crystallized with the franklinite and
r'ed zinc ore of Sterling, New Jersey, and its vicinity.
WOLLASTONITE.-This species forms considertable masses in the
larlge vein already noticed in Grenville, where its associates in the
veinstone are pyroxene, orthoclase. quartz, apatite and sphene. In
smaller specimens it occurs with the same associates in a vein in
North Elnlsley, while in Willslborough,  New York, it is found also
in- a vein with grains of green pyroxene, and red granular garnet,
which latter in some part predomlinates to the exclusion of the
other minelials.
As a bed-mineral I have observed it in North Burgess, sparsely
disseminated in a limestone, with small qllantities of green pyroxene, brown mica and apatite.  In the same vicinity, interstratified
with pyroxenite, are interruplted beds of rock made up of quartz
and wollatonite.  Similar associations to these occur elsewhere
in the Laurentian strata.
HORNBLENDE.-The horlnlecnde of the Laurentian limestones is
either in the form of treniolite, or more frequently in green prismatic crystals belongcingc to the variety called pargasite.  The
raphilite, a grayish fibrous hornblende, allied to tremolite, occurs
apparently in a vein with quartz, mica, apatite and calcite. Large
well-defined crystals of dark green pargasite are found implanted
upon1 or imbedded in still larger crystals of l)ale-green pyroxene,
in a vein descrilbed by Sir William Logan as occurring near the
High Falls on the Madawaska, Olltario, cutting across alternating
strata of gneiss and limestone, and having a breadth of not less
than one hundred and fifty feet.  The minerals filling this immense
vein are chiefly a pale grayish-green pyroxene (sahlite), pargasite,




34       TWENTY-FIRST REPORT ON THE STATE CABINET.           [78]
calcite, quartz, mica and black tourmaline, the crystals of the first
named mineral beitng sometimes six inches thick, and as much as
twenty-foulr inches in length, and those of the dark green hornblende occasionally an inch both in length and breadth.  (See
Geol. Can., pages 35 and 466).  This association of pyroxene and
hornblende has been observed elsewhere in the Laurentian rocks
(page 49).  Pargasite is frequently found in the apatite veins in
Bulrgess, and sometimes forms the selvage of the vein where this
cuts a hornblendic gneiss. Although this species frequently occurs
in the guleissoid rocks near the crystalline limestones, it is less frequent, as a disseminated mineral in the limestones, than pyroxene.
In the stratified pyroxenite rocks, small poitions of hornblende,
recolgnizable iby their different crystallization:and their darker
green color, are not unfirequent.  In some localities it appears to
take the place of the pyroxene. and large beds of hornblende
rock, passing into diorite and horlnblendic gneiss, are met with.
A radiated green hornblende, actinolite, is sometimes found imbelded in the magnetic iron ores.
PYROXENE.-Repeated mention has already lbeen made of the
important rank which this species assumes in the Laurentian veinstones, in which the varieties diopside, sahlite or coccolite often
form the predomninant mineral.  Its crystals are sometimes foun1d,
either alone or with mica, imbedded in calcite, or in contact with
hornllenlde, wollastonite, orthoclase, scapolite, garnet, apatite,
spinel, zircon or sl)heine.  It often assumes a granu1lar form, collstituting what is called coccolite.  A white aluminous diolpside is
found with apatite, gieseckite, etc., in Bathurst, Ontario (Geol.
Ca0n., page 467), and the hudsoniite of Orange county, New York,
is a black alunlinous pyroxene.
We have already mentioned the pyroxenite rocks, sometimes
micaccous, and at other times mixed with hornblende, or with
orthoclase, quartz and spherie.  Pyroxene also sometimes occurs
disseminated in the bed; of magnletite, and glains or imperfect crystals of it, generally of a green color more or less deep, are common
in the beds of Ii m:estone, and are also sometimes found in the
associated quartzites.  A  pure white granular pyroxene occurs,
replacing, like serpentine, Eozoon Canadense.  Large masses of a
similar pyroxene are also frequent in these limestones, generally
associated with serpentine, which often incrusts it, and small
nuclei of this pyroxene frequently form the centre of concretionary masses of serpentinle.




[79]      LAURENTIAN LIMESTONES OF NORTH AMERICA.              35
BABINGTONITE. —This rare species, which belongs to the pyroxene group, is said to he found upon crystals of feldspar ill Gouverneur, New York, and occurs undler similar conditions in veins
nearl Arenldal in Norway.
PYRALLOLITE. —This species, the rensellaerite - f Emmons, occurs
in one locality in radiating columnar masses, with quartz, in a
vein, and is also met with in beds, in contact with serpentine, with
pyroxenite, and in another case with  limestone, and enclosing
scales of -mica and of graphite (Geol. Can., page 470).  A compact earthy hydrous silicate of macgnesia, having the characters of
meerschaum or aphrodite, and the composition of the latter, occurs
in cavities in massive renseliaerite in Grenville (Ibid. page 473).
TALC. —This species is closely related to the last, and the two
may be looked upon as dimnorphous conditions of the same
hydrous silicate of magnesia.  In the Laurentian series, talc seems
to be generally replaced by pyrallolite, but in one instance is
observed mixed with carbonates of lime and magnesia, in such
proportions as to give rise to a bed of imlpure steatite (Ibid.
page 469).  Prof: 11. D. Rogers has also indicated talc as occurringt in a vein, with calcite, pyroxene and spinel, in Sparta, New
Je rsey.
GIESECKITE. —This mineral, which the careful researches of
Prof. G. J. Brush have shown to be identical with the rock
namti.ed dyssyntribite by Prot: C. U. Shepard, and with what I
formerly desc:ribed as parophite, is foullnd in larcge crystals in
northern New York, associated with calcite, brown pyroxene and
lica, the aggre.gate doubtless constituting a veinstone. YWilsonite,
which, notwithstanding its apparently distinct cleavagce-form, I
have provisionally included under the head of gieseckite, with
which it is almost identical in compositionl, hardness and gravity,
occurs also in a veinstone, in Bathurst, with calcite, apatite, wvhite
aluainous pyroxene and serpentine.  The mineral which I once
described by the name of algerite, is found in white calcite, among
the Laurentian limestones of Franklin, New Jersey, and has a composition similar to that of gieseckite, although the form of the
crystals appears to be a square prism.  Whatever conclusions may
eventually be arrived at relative to these hydrous silicates of alumina and potash, the assumption that they are results of a supposed alteration of nepheline, scapolite, etc., is purely gratuitous.




36       TWENTY-FIRST REPORT ON THE STATE CABINET.           [80]
The occurrence of beds of this compound, more or less pure
(dyssyntril)ite and parophite), as a massive or schistose rock, alike
in the Laurentian and Silurian series, leads us to assign to it a
rank and an ori^gin amirag such rocks as serpentine, steatite,
pyroxene, chlorite, glauconite and epidote, all of which silicates,
and many others, have been in most cases deposited as aqueous
sediments generated by chemical reactions at the earth's surface,
and in many clases subsequently modified bly crystallization, or
molecular re-arrangement (Geol. Can., page 581.)
As I have elsewhere remarked,   although spar:'y in structure,
gieseckite and wilsonite have very nearly the chemical comnposition of the hydrous potash-mica, marglarodite.  In like mannler the
sparry silicates, plyrallolite alld logoanite, correspond to the folitted
species, talc and pyrosclerite, of which they have the elementary
composition, although  lifferingr entirely in structure ([bid. page
49 ).
LOGANITE.-This prismatic hydrous species, which I first described in 1848, has recently acquired a new interest.  It occurs
in several places as a veinstone, in one case filling the central portion of a vein of apatite, and inclosincg calcite and sphene; and in
another, in considerable masses, with large crystals of mica, imbedded in a great vein of p)yroxene.  Evidence of its occurrience
as a sedimentary mineral is afforded by the fact that in one locality
it forms the enclosing and filling material of the Eozoon.
[This species, numerous analyses of which will be found in the
eology of Canad,   ge 49, has been by Dana (Mlineralogy, 4th
edition) referred to pyrosclerite, wbhich he however described as
possessing -ian eminent basal cleavage, and in fact identical with
the foliated micaceous minerals kaemmlererite and vermiculite.  I
have maintained the distinctness of loganite fi-om these, first, from
the greater amount of water in its composition, and, secondly,
from the entire absence of foliated or micaceons structure.  Specimens declared to be the original pyrosclerite from Elba, which I
have since examined, have, however, a sparry aspect, and a cleav8age
resembling that of pyroxene and loganite.  The difference in composition between loganite and pyrosclerite still remains to be got
over; but if these two minerals are to ]be identified, neither of them
can be confounded with kaemmererite or vermiculite, from which
they differ as pyrallolite does from talc.]
In the Geology of Canada, page 490, attention has been called




[81]      LAURENTIAN LIMESTONES OF NORTH AMERICA.                  37
to several other hydrous alurnino-mantgne-sian silicates approaching
to loganite in collmposition, and resembling serpentine or pyrallolite in sensil)le cha;racters.  Two of these, described and analyzed
by Dr. Beck, occur in the Laurentian limestones of Orange county,
New York.  These form  altogether all interesting and but little
understood group of minerals, which are perhaps most important
in the history of the crystalline limestones than has hitherto been
sulpposed.
ORTHOCLASE. —This species is common in Laurentian limestones,
generally with 1)yroxene and spherne, and sometimes accompanied
bly scapolite olr a triclinic feldspar.  The orthoclase of the veins is,
ias I have shown, sometimes a very pure potash-feldspar, while the
variety named loxoclase by Breithaupt, which occurs with pyroxene in a Laullentian vein in Hammond, New York, wals fo)und by
Smith and Birtsh to have a predominance of soda (Geol Can., p.
475).  La:rge isolated crystals of white orthoclase are found, with
spinal, apatite and ftl ro, in a veinstone of lamellar link ca,'bonate
of lime in Ross.  The perthite of Burgess, which probably belongs
to a granitiC  veinstonle, is also an examnple of an orthoclase with a
laroge aniount of soda.* An orthoclase, reddish-lblownl in color, like
the perthite, but without its aventurine-like reflections, also occurs
in Burgess, mixed withl a little quartz, andl sometimes with gl'een
apatite, in the midst of a large vein chiefly of apatite and -calcite,
forming a grianite-like vertical layer, eqluidistant from  the two
walls of the vein.  Orthoclase is sometimes disseminated in the
beds of pyroxenite which accompany the Laurentian linmestones,
and are in that case interstratified with  eclds of an aggregate of
orthoclase and quartz, forming' a granitic  neiss, into which the
pyrlxenite graduates.
OLIGOCLASE. -To  this species I refer provisionally, a white
translucent triclinic feldspar, which occurs in small masses with
orthoclase, pyroxerne and sphene in a vein at Grenville, already
noticed.  A similar white feldspar, recognizabl)e by the }beautiful
striation of its cleavage planles, occurs with pyroxene and sphene
in Willsborough, New Yoirk, and a dark green triclinic feldspar is
found with apatite, pyrites and miagnetite ne ar Dover, New Jersey,
and with magnetite and allaniite at Port Henry, New Yoik.  None
* It has since been shown by Gerhard to be made up of thin layers of reddish orthoclase
and whitish albite. See Dana's Miaeralogy, fifth edition, page 356.  T. S. 1I.




38       TWENTY-FIRST REPORT ON THE STATE CABINET.             [82]
of these, so far as I am aware, have been analysed.  The peristerite of Thompson, which, as I have shown, is an opalescent
all)ite, containing, however, a small portion of lime, belongs to a
Laurentiian veinlstone, and is accompanied by quartz and orthoclase.
Portilns of a feldspar are occasionally intermixed  with the
pyroxenic and hornlblendlic strata accompanlying the Laurentian
limestones.  This in some cases is orthoclase, as remarked above,
bult at other times is evidently a triclinic species, givinlg rise by
its admixture with hornblende to a kind of diorite.  The great
beds of rock, composed chiefly of labradorite or related triclinic
feldspars, whlich have been elsewhere descrilb-ed as belongling to the
Laurentian system, occur in that upper and unconformable division
which has been designated as the Upper Laurentian or the Labrador series.
ScAPOLITE.-Underr the head of scapolite and its various synoinyms, mineralogists have included a number of dimetric silicates
allied to the feldspars, and sustainingo, to one another relations
similar to those of the different triclinic feldspars; the extremes
being dipyre, the least basic, and meionite, the most basic of the
series.  Scapolite abounds in many of the Laurentian veinstones,
often associated with pyroxeJne or sphene (sometimes with orthoclase), and frequlently in detached crystals, imbedded in calcite.
It will not improbably be found in the crystalline agogrlegates
which make up some of the stratified rocks of the series, and has
lbeen observed by Gimbel under such conditions in Bavaria.  See
p)ages 47 an3 67.
PHLOGOPITE.-ThC  crystallized mica of the Laurentian calcareous veinstones is a magiiesian mica, and belongs to the species
phlogopite or l)iotite.  The crystals, which  occasionally afford
laminiit two feet square, are found imnbedded alike in calcite, dolo.
1nite, apatite, serpentine and l)yroxene.  Packed close together,
with but little intervening matter, large crystals of magnesian
mica sonmetimes line the walls of veins whose centre is filled with
apatite.  The laminm of the large mlica crystals are often contortecl, and sometimes hold between them thin plates of calcite or
quartz, or flakes of plumliago.  In one case already noticed, a
vwell-formed crystal of apatite was found imbedded in a prisml of
nlica, which had evidlenitly crystallized arounld it.  Some of the
finest crystals of mica of modelrate size occur imlbedded in serpenitille. or with civystallized i)yl oxene, in calcite.




[83]      LAURENTIAN LIMESTONES OF NORTH AMERICA.              39
Small plates of mica, probalbly a magnesian species, abound
both in the limestone beds and the pyroxenites, and sometimles
form layers of a schistose mica-rock, interstratified with the latter.
Non-magnesian micas, belongiing to the species muscovite, nimargarodite or lepidolite, are occasionally found in the quartzo-fecldspathic veins of the Laurentian series, where compounds of linme
and magnesia are wanting; but it is not certain whether they ever
occur with the calcareous veins or beds.  As already remlarked.
the chemical composition of gieseekite, and of the minerals which
we have provisionally associated with it (wilsonite, algerite and
dyssyntribite) is identical with the hydrous mica, margarodite,
which is thus represented in the L:lurenti.all series by these sparlry
silicates, precisely as talc is there represented  bly pyra llolite
(Geol. Can., pages 482-486 and 492).
MARGARITE.-This species, the emerylite of Dr. J. Lawrlence
Smith, which may be regarlded as a hydrous limne-mica, is mentiolled by Blake as occurling o with corundum, spinel and calcite in
a Laurentian vein.,wtone in Vernon, New Jersey, but has not been
elsewhere identified.
CLINTONITE. —This mineral, somewhat related in composition to
the preceding species, occurs in several localities in Orange county,
New York, with spinlel.and( chondrodite, in calcareolls veinstoiles.
It has also been observed, with small crystals of blue spinel, in a
calcareous matrix, in Daillebout, Quebec.
TOURMALINE. —This species frequently occurs in the calcareous
Laiur-entian veins, with pyroxene, hornblende, apatite and calcite.
The finest crystals of brown tourmaline in Canada have been follnd
in veinstones of flesh-colored calcite, either with or without pale
green pyroxene, or in a veinstone of translucent quartz.  Black
tourmaline is also occasionally found with pyroxene, but is more
generally met with in the granitic veinstones, with orthoclase and
a non-magnesian mica. Tolln rmaline, in grains or imperfect cirystals,
also occurs in the stratified rocks of the series.  In one instance it
appears in small knot-like masses, in an impure grayish limestone,
apparently marking the planes of st'ratification.
GARNET.-ThiS mineral frequently occurs in the veins, sometimes imbedded in orthoclase or in quartz, at others in calcite. or,
as at Willsborough, New Yoirk, fornlms cgranular mnasses, associated




40        TWENTY-FIRST REPORT ON THE STATE CABINET.            [84]
with wollastonite and pyroxenle.  Ga-rnet is moreover of frequent
occurrence in the strata associated with the limestones, sonietimes
dissemillated in grains in the pyrloxellites, and more often in
accompanying beds of quartzite, in which it sometimes forms
layers of red garnet rock.  The strata of gneiss in the vicinity of
the limestones often abound in gairnet.
IDOCRASE.-This species, althoullgh less ab)undant than garnet, is
found in several places associated with it.  The ocurrcnce in a
vein of a skeleton-crystal of yellow idocrase, enclosing orthoclase
and zircon, has been noticed on page 50.  The same vein afibr(ls
crystals of' cinnamon-stole garnet.  I have elsewhere described a
boulder of crlystalline carbonate of lime, apparently a veinstone,
founld on the Ottawa, in which were detected small square prisms
of idlocraset, dodecahedos of garnet, and terminated tialrlgular
pr'islms of tourmaline, all three species being of a bright yellowishbro()ll color.
EmDOTE. —This species occutrs ill several localities in calcareous
veins amollg the Laurentian irocks in New York and New Jersey,
solnetimes crystallized with orthoclase, I)yroxene and graphite, or
as described b)y Prof. Henlly Wulrtz, inibeclded in fine crystals in
calcite, in Byram, New Jersey.  A  sl)ecimen from  Cold Spring,
New York, exhibits a crust of small crystals of epidote coatillg a
large prism of pyroxene.  Although not hitherto detected in alny
of the Laurenltian veilIs in Canada, epidote enters largely into the
conm)osition of the lpyroxenic alld feldspathic rocks which aire associated with the limestones in the vicinity of the iron ores of Belioiiot and Seymour, Ontario.
ALLANITE, which is regarded as a cerium-epiclote, occurs in some
of the L-aurentian veins, associated with apatite and tourmaline:at
Ticollderoga, and with quartz, feldspar and  magnetite at Port
Henry, New York.
ZIRCON. —This sl)ecies is of frequent occurrence in the calcareolls
veins, associated withl pyroxeiie, hotrnblende, orthoclase, scapolite
and sphcne.  In Munroe, Orange county, New  York, crystals of
zircon al)ounld ill a galiitge of magnetic iron ore with pyroxene and
feldspar, andl according to Durocher, zircon is also met with in the
mntaglletic iron of Solberlg, near Arendal, and at Laligsoe in Norway
(Ai-i. cdes iltnes 1-4], xv, 229).  Zrl'conl is also foundl disseminated in




[85]      LAURENTIAN LIMESTONES OF NORTH AMERICA.              41
large proportion in a ganguie of black hornblende with a little feldspar, in Cornwall, Orange counllty.  Large and well-defined prisms
of zircon, which occur with apatite and feldspar in Hammond,
St. Lawrence county, New York, are sometimes, like the idocrase
noted -above, skeleton ctrystals, filled with carbonate of lime (Beck.
Miiineralogy of Neuw York, page 381).
SPINEL.-This mineral is often albundant ill the calcareous Laurentian veins, generally associated with chondrodite, pyroxeln,
clintonite, serlpentine, ilmenite, anil other species.  Sometimes it
is imbedded in calcite without any other mineral, as in Burgess,
where a mass of pink limestone, probably a veinstolle, has afforded
fine crystals of black spinel an inch in diameter.  In Ross, similar
crystals occur in -a calcite vein with orthoclase, fluor-spar.land
apatite; grains of the latter mineral are frequelltly imbedded ill
the spinel crystals.  Small crystals of spinel are sometimes found
disseminated in what appear to be stratified limestones. Although
the spinel of the Laurentian limestones is generally vblack, blue,
red and green varieties are occasionally met with.  TlIe dysluite
or zinciferous spinel is worthy of notice, as occurring in Stirling,
New Jersey, with other zinc-bearing lminerals.
VOLKNERITE.-To this species, a hydrous aluminate of magnesia,
Dana has refelrred the houghite of Shepard, from  St. Lawrevnce
county, New York, which occurs associated with crystals of spillel,
and having the same octahedral form, but distinguished by a low
specific gravity, and a softness like steatite.  A gradation is seen
firom the hard spinels to the houghite crystals, which still include
a portion of spinel, but consist chiefly of'a matter having the composition of volknerite.  It would seem that the crystallogenic force
of the spinel has given its form  to accompanyilng vlknerite.
Small steatitic octahedrons, apparently similar to the houghite,
have been found  imbedded in serpentinel in Burgess, but require
farther examination.  The hydrotalcite, which is regarded as idelltical with v6lknerite, occurs with ilmenite in the Laurentian serpentine of Snarum, in Norway.
CoRuNDUML.-Crystal lized corundum, white, blue or red in color,
occurs with associations similar to those of spinel, which occasionally accompanaies it.  Crystals of corundunl line cavities in the
large spinels from  Orange county, New York.  The redl erystsals
froml Vernon, New Jersey, as described1 by Blake, like the idlocrase
6)




42       TWENTY-FIRST REPORT ON THE STATE CABINET.             [86]
and zircoll mentioned above, often present a mere outel' shell of
colrulllduln filled nup with other minerals.  The corundum found inl
Canladal is imbedded in calcite with pyroxene, sphene and mica,
and very  closely reseml)ling those associated with it at Vernon.
QUARiTZ.-The presence of crystalline quartz in tEe Laurentian
veinstones has already l)een repeatedly noticed.  Sometimes, as at
Goulvelnleur, New York, it is found in crystals with iounlded angles imbedded in crystalline calcite; at other times implinted on
al)atite, as ill Burgess, where the crystals are occasionally ametiystile, smoke-blrown or opaque-red in color, andl unlike the apatite,
to whllich  they are posterior, have not their anglles rounded.
Quarl'tz is of very common occurrence in the veins, minagled with
wollastonite, pyroxene or orthoclase, and a vitreous quartz is
sometimes the gangue of crystallized brownli tourmaline' alnd of
np:itite.  It is also frequently disseminated  in grains or small
masses in the limestone beds, or forms in the accomnpanying, strata
]layers, in which it is sometimes mingled w-ith wollal;tonite, with
glreelln )yroxele, with garnet, or Nwith orthoclase.  Besides these,
thin layers and massive beds of quartzite are frequent, and are
often interstratified with the limestones.
SPrENE —This is one of the most comnmoln minerals of the calcareolus Laurentlan veins, anl(l its occurrence and associations have
already been repeatedly niiti')ned.  It also occurs in small grains
or clrystals,  cenerally olive-brown in color, disseminated in the
stratified limestones, or more fiequelntly inl the associated pyroxenic and feldspathic strlata.
RUTILE —ILIENITE.-Both of these species are occasionally found
crystallized in Laurentian veins with spinel, chondrodite, corllunduin, etc., or imbedded in serpentine.  The imbedded grains and
masses of ilmenite, often of glreat size, ald so()metimes intermixed
with rutile, which occur at Bay St. Paul, Chatelau Richelr, and elsewhere in the province of Quebec, appear to belong to the Upper
Laurelltian or Labrador series, and neither of these minerals have
as yet been niet with in tle proper Laulrentian rocks in Canada,
atlthough occullinl in several localities in New York.  The ilmenite criystals, with serpentilne, from Snaruim, and with hornbllendle
and calcite fronm Kx.rageieoe, are well known to mineralogists.
MAGNETITE.-Tllis important iron ore, which constitutes one of
the principal sources of mineral wvealth to the Laurentian regions




[87]       LAURENTIAN LIMESTONES OF NORTH AIMERICA.                43
both of North America and of Scandinavia, has been shown 1)b the
explorations of tile Geological survey in Canadal to occur in g(re:t
beds, iilterstratified with the limestones of the series or ill their
vicinity.  This is cletarly the clse with all the considerable deposits of ore hitherto examined in Caniada  yet, as in the c~ase of
the crystalline limestones, there are those who ma:intain the erulnptive character and igneous origin of these masses of ore.  Emmons
looked upon the mcagnetic iron ores of llolthern New York as
intrusive masses, alnd Prof. H. D. Rogel's ill like manner re(.ardcd
the magnetic ir(on ores of the Laurentian strata of New Jersey nlot as
l)eds, but as real veins of injection (Fiinal 1Retport, Geol. I. Jersey,
page 22).  Durocher in like manner, in descrilbing the deposit of
the same ore at Bispberg in Sweden, spealks of it as a " )ltltonlli
rock" inlje ted amon(g the beds of gueiss in the plalne of stlratification, and having a thickness of frolm eighty to one hundred feet.
He elsewhere speaks of the injection of the masses of a sinliltar
ore near Arendal (Ann. des MIines, [4], xv, pp. 203, 204, 225).
A  careful study of his descriptions and plalls vill, however, we
think, show that these great deposits of Scandinavia lare, like the
similar masses of ore in Canada and the United States, interst-ratified sedimentary layers.  At the same time there exists in favor
of the view maintained by Emrmons, Rogers, Durocher, and other
geologists, evidence similar to that adduced in favor of the elruptive origin of crystalline limestones; that is to say, the fact of
veinstones consistingi wholly or in part of magnetic oxyd of iron,
An interesting, examplle of tlhis occurs near Dover, New Jersexw-here la-ge crystals of apatite occur in a giangue comnposed of triclinic feldspar tiand iron pyrites, imbedded in which latter occu-rs
crystalline magnetite in rounded masses, sometimes half a:l illch
in diameter, that were at first taken for ilmenite.  Similar associations [lave been observed in other veins, and it is not imprloba)l)le
that the mixture of magnetite wvith a   largle proportion of zircon,
descril)ed under the head of this species, may be from a veinstone.
Allother and an instructive instance is that described by Sir Willia,'; Loganii as occurring in the township of Ross, opposite Portage
du Fort.  Here a vein, or rather:l group of reticulating veins and
cracks, is seen in a white grlilanular Laurentitan limestone, cuttingl
across the stratification, and sendinol off branches on either side in
the plane of the limestone beds.  These veins vary from  a sixteenth of an inch to two or three inches in thickness, and are
filled with highly crystalline mnagnetite, which in co(ntact with the
n                   n r




44       TWENTY-FIRST REPORT ON THE STATE CABINET.            [88]
limestone presents in some parts large cubic and cubo-octahedlral
crystals.  Two largre veins, niade up almost entirely of orthoclase
and highly crystalline rmag(netite, eaLch mineral often presenting
cleavage planes of a square inch or more, have recently bleen met
with in Buckingham, on the Ottowa.  In these veins which intersect the gneiss, and have a breadth of nearly eighty feet each,
the lmagnetite foirms more than one-half the weight of the veinstone.  Other and perhaps larger veins of magnetite may exist,
and may have given countenance to the theory of its eruptive
origin, but it is probable that few of the workable deposits of
this ore are of the nature of veins.  They appear to be conformable to the stratification, and are cut by the same veins which
traverse the adjacent gneiss and limestone.  Moreover, they are
impregnated with the same minerals as the accompanying strata;
grains of apatite, scales of graphite, calcite, feldspar, pyroxenle
and garnet are occasionally fo)und disseminated in the ore, which,
by a predominance of some of these mixtures, passes into the
accompanyiny gneiss, or into hornblendic or pyroxenic rock.
HEMATITE.-Amiong the Laurentian rocks of St. Lawrence and
Jefferson counties, New York, several localities of crystallized red
hematite, or specular iron, with brown spar andl dodecahedral
quartz, are met with, accordingl to Beck, in small veins.  In like
manner, in the township of Bristol, on the Lac des Chats, specular
iron, in broad crystalline plates, occurs with quartz, and also with
calcite, in what appear to be true veins cutting the crystalline
limestone and the adjoining gneiss.  The octahedral peroxyd of
iron, martite,which I describe(l several years since as occurring with
green hornblende, orthoclase and quartz, from Munroe, New York,
is probably from a veinstone (Amer. Jour. Science [2], xiii, 372).
The workable deposits of the granular and compact varieties of
hematite,  which col;stitute the red iron ores of Northern New
York an(i of Canada, appeal, however, to be in all cases of the
nature of beds, and the remarks with regard to the relation of
the Inagnetic ores to the stratification are equally applicable to
the present species.  Although the great deposits of iron ores in
the Laurentian rocks are chiefly of the magnetic species, bedis of
red hematite have been described as occurringr in MacNab, on
Iron Island, in Lake Nipissing, and elsewhere.  In the Laturentian region of northern New  York, in like manner the magnetic oxyd is the prevailing ore, especieally in the eastern portion,




[891    LAURENTIAN LIMESTONES OF NORTH AMERICA.                45
while in St. Lawrence corunty the red hematite predlominates, and
forms very extensive deposits.  In Beverley and ill Bastard, ()Ontario, snmall beds of this ore occur in the Potsdam sandstone, which
there rests directly on the Laurentian, and some of the other
deposits of red hematite, already alluded to, may perhaps be
found to rest upon this allcielnt system  instead of fornming part
of it.
The magnetie and hematitic iron ores are sometimes intimately
associated both in Scandin.avia and in Canada.  A specimen now
before me from the great magnetic ore bed in Hull, Qllebec, consists of two p:uaallel layers, each about anl inch thick, the one of
coarsely granular magnmetite, and the other of compact red herlatite, not at all mlagnetic, the two being r somewhlat interminigled for
half an inch at the junction.  Grains of cgreenish feldsplar are disseminated   in the magnetite, and b)oth it and the hematite contain
imbedded crystalline plates of grtaphite a tenth of an inch or more
in diameter.  A  film  of scaly graphite, nloreover, coats the free
surfiace of the hematite layer.
FRANKLINITE, ZINCITE.-The two remarkalble ores, which are
found together in Sterlin(r and Franklin, NeSw Jersev, were lonlg
since described by Prof. H. D. Rogers as occutrring in veins which
traverse the crystalline limestone of the region (Final Report,
Geol. N. Jersey, 1840, pages 63, 64 and 69-71).  The red oxyd
or zincite sometimes fol'ms the gangul e of the firanklinite; at other
times the two ores are associated in a matrix of calcite, whose
peculiar composition has talready been noticed under its proper
he'ad.  The silicate of zinc, willemite, is also occasionally found
with the fliranklinite in the calcareous veinstolle.  It remains to l)e
seen whether these ores do not, like the magnetite, occtir in the
stratified rocks of the region.  These zinciferous minerals appear
to be confined to a small area in New Jersey, as they have never
yet been seen elsewhere in the Laurentian rocks of North America
or of Scandinavia.  They are sometimes accompanied by colorless
transparent bllende.
IRoN PYRITES.-Culbic iron pyrites is of not unfrequent occurrence in the calcareous Laurentian veins, sometimes in distinct
crystals, imnledded in calcite, and at other times filling up considerablle portions of the veins, as in some localities in Burgess,
and.associated with apatite, pyroxeine or mica-.  In an instance




46        TWENTY-FIRST REPORT ON THE STATE CABINET.             [90]
mentioned above, a massive pyrites is the galgue both of crystals
of apatite and of magnetite.  The l)yrites from veins in the L.1iirentitian rocks occasionally contains cobalt and nickel, sometimes in
large proportions.  A bronze colored, compact, imnpalpalble variety, folund in irregular reniform  or globullar nmasses, with copper
pyrites, in North Burgess, gave me onl analysis 3.47 per cent of
cobalt and 2.21 per cent of nickel.  It contained no arsenlic.
It would seem  scarcely necessary to mention the existence, in
the strata, of a mineral so genlerally (iffutised as pyrites, were it
not for two reasolns: first, to recall that pyrites is sometinmes disseminated in the beds of magnetic oxyd, so as to render the roasting of these, to remove the sulphur, a necessary 1)relimillary to
the smelting process, and second, to remark that the banlIls ill the
Laurentian gneiss are sometimnes imupregnatedl with pyrites to stuch
an extent that their weathered surfa'ces become stained of a reddish hue from its decomposition.  These il'lon-stainied strata conlstitute what the German miners call frthlbands, anild are oftenl of
economic interest, fr'om containing   ores of more precious metals,
such as copper, zinc, cobalt, nickel or eNven gold alnd silver, either
impregnating certain layers, or accumulated in veins, which illtersect the fahllland.  From  a certain similarity in their cllemical
relations between all these metals, it happens that their sulphurets
are very commonloy (associated in nature, so that a deposit of pyl'ites
is nOt unfrequently impregnated with or accollllnpaied 1by the sulphurets of more valuable mnetals.
MAGNETIC PYRITES is occasionally found in the Laulrentiall veils
ulider conditions similar to those just mentioned for culbic pyrites.
Near Portleuf, Qulebec, a veinstone of calcite encloses small crystals of green pyroxene, together with' collsiderable masses and
imperfect crystals of maglnetic pyrites.
COPPER PYRITES.-This ore is occasionally found wIith the Lalirentian limestonies both in Canada and in New York (Geol. Can;.,
p)age 692).  In some cases it occurs in small irregultc r veins, with
calcite, and occasionally with iron pyrites rich in cobalt and nickel, but unaccomnlanied bly the minlerals which generally charlt:cterize the Laurentianl veinstones.  In Escott, Onlltalio, however, it
is found in considerable quantity, in a true granitic veinstone, withl
orthoclase, quartz, black tourmnaline and mnicar.  Ill the same towinship there was wrou,ht:1 deposit of this ore, havigi,, apparently




[91]      LAURENTIAN LIMESTONES OF NORTH AMERICA.                  47
the foi-rm of a small lenticular bed, ill immediate contact with a
bled of magnetic ilonll ore (I6id, page 6i3).  Small veins filled
with cubiic tInd maglnetic irion l)yrites, copper pyrites and blende,
with a little calcite, are found traversinog  a maonesian limestone
in IMaLdoc.
[In anllother locality ill the same township similar veins, having
a gtlngue of mixed calcite, bitter-spair and quartz, carry besides
copper pyrites, gr:llena and the two species of iron pyrites just
melltioned, mispickel and argelntifet ous f ahlerz, the latter species
piredloniin:ltillg and beinll ass{cia;ted with a little gold.  The mispic/kel of the locality just describ)ed contains a tl'ace of cobalt.
The  same mliinelral is ftound in several other localities ill that
vicinlity, which morl'eover affolds s tstllnAtpret of antimihony in small
quantitics dlisseminated in dolomllite, and in one insttance associated
Nwith tremllolite.]
[BIrsuTIIINE. —The silllhuret of lismlutll is foiund in crystalline
masses of considerable size in a vein cuttilg a plumnbaginous limlestone ill L;tke, in the province of OntLario. It is imbedded in quartz,
and immediately associated with plumbaol o and brown tourinaline,
delicate prisms of which are occasionally found penetrating  the
bisnutltinle.  Millnute porltions of native bismuth are occasionally
met with in the vein, (lnd carblonate of lbismnuth, probably fi-om the
decomp)osition( of the stll)lhlluet, occurs iear the surface.  This vein
belongs to the thi'il class, alrea(ly   describcd, and in sonime parts )y
an adlnixtuile of mica and calcite passes into anll aggrlegate which
migrht be mistaken for a, coar!sely crystalline limnestone.  These
calcarleous portions of the veil lare pinlkish ill color, with'yellow
p)hiogopite, and contain crystalline mllasses of iron pyrites.]
SULPHURET OF MOLYBDENUM. — This species, as mentioned in the
(Geolor/ of Cacotacla, pages 503 and 754, occurs in several localities in tile Laturenltiall  rocks.  In the vicinity of Balsam Lake it is
found in small quantities, associated with scapolite, pyroxene alnd
iron pyirites, in a huge vein of quartz whichll traverses the crystalline limestones of that rlegion.
[GoLL). —The occurel'nce  of native gold has already been mentioned  oil pagte 66.  Small portions of the 1precious metal have
also been tletected in assalys of pyiitifecous quartz froml Belmont,
and it is said in qutartz from  otllher localities, atnd also associated




48        TWENTY-FIRST REPORT ON THE STATE CABINET.             [92]
with beds of silicious rock impregnated with plumnbago fi'om more
than one locality.]
GRAPHITE OR PLUMBAGO.-This milnerall is occasionally met with
ill most of the stratified rocks of the Laurentian systemll; not ojnly
the limestones, but the gneiss, pyroxenite, quartzite andl pyrallolite
beds sometimes hold disseminated graphite.  It is moreover met
with in the iron ores of the series, as in Hull, Quebec, where large
scales of graphite are imbedded in the crystalline  malrgnetite, and
also in Franklin, New Jersey, where, accordinig to Dr. Fowler, the
graphite disseminated in the magnletic iron ore is an obstacle to
the workingr of it in the forge (Roger's, Final Rep. Geol. N2ew
Jersey, page 64).  Beck has also describe(l, as occuring near the
Natural Bridgre, in Lewis county, New York, a mixture of chlorite,
graphite and red iron ore, the latter amoultillg to about one-half
of the mass (Jlneralogy of NVew Yo'rk, piage 26).  The presence
of graphite in the hematite which is associated wvitli magnetite in
Hull, has already been noticed above.  It is, however, chiefly in
tle limestones that we find graphite dissenminated, sometimes so
finely divided as to rrive a1 lluish-grley tinlt to certain bands marking the stratification, and at other times appearing in thin detached
films or flakes, also marking the stratification.  Portions of the rock
il this way sometimnes become higlhly charged with graphite, and
llmaly fotrm  workable beds, lbut it is doubttful whether accumulations of pure crystalline gra'.phite ever occur in the stlratification.
Specimens of an impure am)orphous graphite have lately bleen
brought from  Clarendon, Onllta:io, where it is said to form a bed
of fifteen inches in thickness, in a fine grained mica-slalte.  The
mineral is sub-conchoidal ill frlactulre, 1earthy, bluish-blIack in color,
(lull, but assuming the lustre of rTl.'phite under the 1)urnisher. It
loses by ignition only 0.4 of volatile lmatterC; by a p)rolonged calcination in the open air, however, the,grlaphite is burned awvay,
leavin)g 66.16 per cent of blrowllish-yellow  residue, Nrwhich yields
to acids a little lime, magnesia and oxyd of iron, and then consists
chiefly of a silicate in large part alumillcus.  This anhydrons
arglillaceous rock thus conltains very nearly one-third its weiglht
of amorphous or uncrystallinle graphite.
Crystalline graphite is olne of the most frequent minerals of the
Laurentian veins, in which it occurs under a variety of aspects,
solnetimes as large plates, or hexagonal tlables, disseminatetd in
coarlse-grainedl calcite, vitreous qllartz, orthoclase or 1)yroxene, in




[93]      LAURENTIAN LIMESTONES OF NORTH AMERICA.                  49
scales between the laminTe of mica crystals, or else forminog solid
masses in the Veini.  These masses, when pure, are cgenerally madeL
of broad and thick lamina, the edges of which, in some cases at
least, are at right angles to the sides of the vein.  In some cases
a lar1ge vein will carry two or mnore bands or lyers of pure or
nearly pure gnlraphite, selparated from  each  other and fronm  the
Twall-rock by  feldspar, pyroxene  or quartz.  Occasionally  the
grlphite found in these veins is finely gralinular, or like that fronm
Warirensburgh, New York, breaks easily into rectangu1lar mLasses,
which exhibit on certain of the  fractured  surfaces a, pecliiar
finely waved aspect, due to a structure which nlmay!be desclribed
as consistino, of layers of a millimeter or less in thickness, tolerably regular, and made up of minute and nIlarrowv laell, arraed11'1'
at riglht angles to the layers, and presenting a filbrous or columnar
aspect when broken across.  W\re]C   the firacture is with the layer s,
and thus exposes only the ends of the lamelhl, a (rallul:ar surf1ace
is presented.  Fractures at right angles with the layers show  111
undulatingY surface, recalling   that of certain waved maplle woods,
and due to the faict that the fibres of the successive layers are nlot
quite parallel with each other.  This Lautrentian graplhite, according to Pr1of. C. F. Chandler's ana1lysis, consists of carbon, 64.06;
carbonate of lime, 32.90; the rernaining three pei' cent beilg
chiefly silica and oxyd of iron.  The carbonate of lime is invisibly
diffused through the mass, which effervesces freely with acids.  It
is not in any way connected with the peculiar waved structure,
since the Ygraphite from the famous mine of Marinski, in the Government of Irkutsk in Siberia. which presents a structure precisely
similar, contains no carbonate of limle, and( only small q(luantities of
earthy impurities, amounting, according to Dumas, to 3.7 per celnt
of the purest specimens.
The Laurentian graphites, then, besides their visil)ly  present
foreign minerals,  may contain finely disseminated inlpurities, which
detract from their cconomicall value, and can only be detected by
analysis.
A Laurentian graphite from Patterson, New Jersey,  crystallized
in broad lamelle, gave to Prof. Chandler, 21.0 per cent of pyrites,
finely (lisseminated between the laminmc.  This graphite, -which ~by
exposure becomes covered with aln efflorescence of stllphate of
ilron, gave also portions of silica, alumina  and limne, apparently
-derived from  s(ome mineral like SCal)polite, (lisseillnatc(l throll-ll




50       TWENTY-FIRST REPORT ON THE STATE CABINET.            [94]
the lmass, and also enclosed  small but distinct brown prisms of
apatite.
On the other hand, a gral)hite from the third lot of the second
range of Grenville, Quebec, closely resembling the last in appearance, was found to be of great purity.  By long continued ignition
it burlned away, leaving only 1.27 per cent of foreign matter,
which consisted of small, colorless, brilliant glrains, apparently of
quartz or feldspar, with a minute quantity of ftawn-colored flocculi.
Portions of the specimens of graphite sent from  C(anada to the
Exhibition at London in 1862, were furnished to Mr. Regnault, the
eminent French chemist and physicist, who has since made use of
them in an investigation on the specific heat of this form of carl)oa.  Incidental to this inquiry, they were submitted to a carefull
analysis by Mr. Cloez; (after being calcined to expel any traces of
moisture, they were burned in a current of dry oxygen and showed
the fact, already suspected l)y RecTnault, that a portion of hydrogcli enters into their composition, and is only separated by prolonged ignition in a current of dry chlorine, which at the same
time separates the earthy implurities, in the form of chlorids, and
leaves the graphite an almost chemically  pune  carbon.  The
analysis of a specimen, probably from the same locality with that
which gave me 1.27 per cent of ash, cgave to Cloez, carbon, 98.56;
hydrogen, 1.34; ash, 0.20 =  100.10.  Two other specimens of
Canadian graphite gave him, respectively, 12.60 and 23.40 per
cent of arg-illaceous ash (Annl. de Chim. et de Phys. [4], vii, 450).
The lalnellar graphite ablove noticed, like that of most of the
sinmilllar grlaphites known in Grenville and the adjacent region, occurs
in veins traversing the crystalline limestones, which are themselves
mIore or less impregnated with graphite.  In other cases, however, the wall-rock is gneiss, as in Ticonderoga, New York, where,
in addition to the graphite veins, interstiaatfied layers highly clharged
with lanmellar crystalline gr-aphite are extensively mined in the
Laurentian gneiss.  A small vein, also in gneiss, occurs near Mud
Lake, in Loughborough, Ontario.  The graphite of the Laurentain veins is sitlilar in its characters to the crystalline graphites
of Ceylon, the mineralogical resemblances of whose rocks to the
Laurentian series we have already pointed ouit.  These graphites
are distinluished b3y their highly crystalline texture, their metallic
gray streak and lustre, and their comparative frleedom from  ordinar1y  earthy impurities, although, as we have seen, they may include iadlmixtures of carbonate of lime and sulphuret otf iron.




[95]      LAURENTIAN LIMESTONES OF NORTH AMERICA.                51
There is, however, another class of graphites belonging  to the
stratification, and evidently of sedimentary origin, containuing,   a
large ladmixture of earthy materials, such as sand and clay. These
graphites are generally amorphous, or but imperfectly crystalline,
and ordinlarily give a much darl'ker streak than the purer varieties.
To this second class belolgs the earthy graphite fronm  Clarendon,
Ontario, already described, and that of many other localities, iwhere
the mineral has bleen formed by the alteration of more or less carlonaceous layers in schistose rocks.  The impure plumbaginous
schists from  the Quebec group of the Eastern Townships of the
province of Quebec;  the beds of graphite in the micaceous schists
of eastern Massachusetts, at Sturbridge, Worcester and elsewhere,
which are now recognized to be altered beds of coal; those of the
French Alps, which are associated with fossil plants, and those of
Passau, in Bavaria, where the mineral is disseminated in gneiss
of Lallrentiall age, are also examples of this second class of graphites.   To these we may add the graphite of Borrowdale, in
Cumberland,  which is found in lenticular masses in laltered slates,
and the beds of graphite inl mica-slate, in New Hampshlire, which
in some cases passes into a plumlbaginlous mica-slate, holding gltrnets.  In describing  the latter deposits, Dr. Jackson has observed
that in the town of Goshen the l)eds of graphite are intersected
with cross veinis, which are filled with pure foliate(ld,raphite.
These graphites of the second class are distinguished not only
by the laire proportion of silicious and argillaceous matters withl
which they are mningled, but also by the very general absence of
crystalline texture.  This is so evident a characteristi,. that Sir
Benjamin  Brodie, in his recent researches on the chemical relations
of graphite, distinguishes two varieties-the amorphous, in cluding
that from Borrorwdale and from Passau, and the lamellar or crvstallille, represented by the graphite,associated with quartz f-om
Ceylon, and that from Ticonderoga, New York (Philos. Tl'ransactions 1859, page 249), the latter of which belongs to Laurentain
veins.  The graphites from New Brunswick and from  Grecilanld,
according to him, approach to anthracite in character, and prol)albly, like that of Massachusetts, pass into this variety of mineral
carlboll (Lyell. Geol. Jotr-nal, I, 199.-Hilchcock's Geol. i7_I(sa.,
page 127).  Between the amorphous graphite of Brodie, represented by that of Bor-rowdale and Passau, and the lamnellar variety
fromn Ceylon and from the Laurentian veins of North America,
may ble placed the interstratified graphites of New Hampshire and




52        TWENTY-FIRST REPORT ON THE STATE CABINET.            [96]
of Stlirbrl'idc, MaIssachuisetts, whicll are mnore or less crystalline in
texturle.  It will prolally l)e foulnd tlhat the highlv crystalline
laimellar graphite belonls, iln all cases, to tlrule veins, where a
slow  lprocess of deposit has allowed it to assume that mode of
aggregation  and that purity which characterize other minelrals
thuls deposited.
The presence of grall)hite in veins unllder sucll conditions arnd
asIsociations'as have already been described, implies its separation
from  solution at an elevated temlllleratre, and in this collnection
the curious researches of Brodie, above refeirred to, have shown
that this frl'm of carlbon is possessed of singular chemical proplerties and affinities, which, when farther studied, may serve to explain
its solution and crystallli;-atien.  MeanNwhile, the observations of
Pauli have establlishetl that when hydrate of solda, mixed with
cyanid of sodium, is heated with nitrate of soda to incipient rednless, the carbon of the cyanid separates fromn the liquid mass in
the fourm of gLraphite. Pauli moreover sig(rgests that natiNve grap)hite
may have been sel)arated fionm  certain c'arbon coml)pounds by a
lprocess analogous to this (Philos. M3egy., [4], xxi, 541).  The
direct Iransfiormation into grilphite of carblonaceous matter cannot,
howeNNver, be doubted  by  geologists,  and  such a hypothesis is
therefore untenable for the stratified  gralphites.  This reactioll
described  ly Pauli is nevertheless instructive, as showing that
gralvphite may be separa~ted  fromi   solutions at a temperature not
hiTher than that at which, acclrding to Sorby, the minerals
which accompany it in the Laurentian veins have crystallized,
althlough we cannot, in the formation of these veins, suppose the
intervention of these same chemical reagents as in the experinlent
of Pauli.
Graphite may undoubltedly be fornmed at much higher temperatures.  Its occurrence in cast-iron is -well known; and Brodie,
who obtained, lby dissolvint a graphitic iron in acid, four per cent
of lamellar graphite, fiolund it to be identical in physical characters
with that met with ill nature.  Jacquelain also, by the decomposition of sulphluret of carbon in COlntact with metallic copper, at
800~ Centigrade, obtained, together with  sulphuret of copper,
amorphous graplhite.  Starting fromn this experiment, Jacquelai n
suggests that native graphite may have originated fronm the distillation into the fissures of rocks of volatile hydro-carbons, iwhich
have there, Iby a decomposition similar to that which takes place
in contact with the walls of coal-gas retorts, given rise to a deplosit
Z71V'  lr L U- n




[97]       LAURENTIAN LIMESTONES OF NORTH AMERICA.                 53
of carbon thait has assunied the form of graphite (Cosmos, June 23,
1864).  This hypothesis, evidently inadmissible for the'graphite
fiund. as a disseminated mineral in stratified rocks, is not less so
for that found in veins, where its associates are mineralils whose
lpr(selnce is inlcompa;til)le Avith the high  temperature  supposed.
Graphite, when ignited with carbonate of lirme, gives rise to carl)otnic oxyd, and under similar conditions reduces iron from  its
oxvd to the metallic state.  It even  decomposes the vapor of
vwater at a red heat.  We are hence led to regard the graphite
of bedded rocks.s having been foinrmed by the alteratioll of coal
alnd similar carbonaceleous matters at a temperature below redness,
while its subsequent translation into the veins, and its deposition
in a crystalline fo'rm, tog'ether with various other minerals, as it
occurs in the Laurenltian veins, have been effected ulder conditions
which, althoutgh imnperfectly   understood, prolbably iuicludedl aqueols solutiol, alnld a temperature not ftr below a red heat.
[ANTHnACITE.-Under this n11nie, for wanllt of  better term, may
be described the black carbonl:ceous matter which has allrea'dy
beenl noticed ais associated with native gold, bitter-spar and a reddish ochre, derived firomn tlhe decomposition of the latter, at the
Richardson rmine in Mad oc, Ontario.  The anthracite seem-3 like
the simil(r material associated with qllartz crystals in Herkimer
coullty, New  York, to  have been deposited  contemporaneously
with the qulartz and bitter-spar, in soime  cases lining  the walls of
the vein, and in others appearing in masses an inch or more inl
diamneter in the middle of the veinstone.  It is jet bllack in color,
with a conchoidal fracture and a somevhat resinous lustre, and is
soft and easily crushed between the fingers.
When exposed to heat in Ca titbe it give out somne water, but no
bitumlnillous llntter; in the open air at a red heat, it talkes fire and
b)urns readily without flame, leaving a somewhat labundall     t ash,
whitish and sometimes reddish, consisting   of carlonate of liime
with some silicious and feirrluginous   matter, including    a quantity
of gold.  This metal is visible in the form. of grains and scales in
the recent fractures of the black substance, which, although coallike ill its aspect, resembles more the carbonaceous matter which
has bleenl described in the Geology? of Cactlada as filling veins or
fissures in the rocks of the Quleec group, anid is doubtless derived
fro1m  the transform ation of blitume.:.  This substance, as I have
shewn, is in some cases so falr altered  by oxydattion as to have a




54       TWENTY-FIRST REPORT ON THE STATE CABINET.             r98]
composition like that of anthracite, and is then scarcely distinguish.able from the Madoc mineral.
The gold, as already stated, occurs )both in fine scales, disseminated throurgh the black anthracitic matterl, and in large crystalline grains anld plates, iml)edded  in the bitter-splar, sometimes associated with quartz, l)lack hornblende and iron pyrites.  From
this it would appear that the introduction of the gold was not
only contemporaneous with the deposition of the bitter-spar, but
continued after the introduction of bitumen.
Carbonaceous matters not unfrequently occur in mineral veins
in other regions, and are met with in several localities in the
Laurentian rocks of Scandinavia, where, according to Daubrl e, in
the silver mine of Kongsberg, a matter allied to anthracite and
similar to that of Madoc, occurs in mnammillary masses inllbedded
in the calc-spar of the veinstone, and sometimes peietirated( by
native silver (Ann. des J'lines [4], iv, p. 2(;0).  In other veins in
that region the presence of bitumen is indicated, and in the Ibeds
of magnetic iroll ore, found in gneiss at Dannemnora, small masses
of a matter closely resembling  bituminous coal in composition,
and penetr ated by quartz veins, occur ill the midst of the o0re. See
il this connection Igeistl'om's recent obsel'vatiOlls on the bitumiious gleiss of Werlmland, in Sweden (Alner. Jour. Science, [2],
xlv, 38).  According to Daubri6e, both graphite and allthracite,
-where they occur in the ancient rocks of Scalldinavia, are accompanied by lbitumen. No such.associa;tioiis h1ave hitheirto been obserived
with the grIaphite of our Laurentitan series.
The above details are chiefly taken from the Report on the Gold
of the County of Hastings, already cited.]
P. S. —More recent researches by the Geological Survey of
Canada, have shown that the rocks of Hastings county, Ontario,
noticed on page 48, rest unconformably upon the Laurentian,  and
lbelong to one and possibly two distinct systems.  The uppel and
la11ger portion consists in great parlt of mica-schists and micaceous
limestones, while at the base are great masses of dioriitic.and
horlnblendic schists with iron ore, possil)ly of Hlllonian age.  To
the basal portion of this upper series belong the stcatite, pagle 79 
as also the gold, page 66; the bismuth ores of page 9 1, and the
anthracite of page 97.  The upper wvorks of Hastings arle noticed
by me in the American,Joturnal of Science, for July, 1870, page
85.                                                      T. S. H.