ilftfitrrN LIBRARY I UNIVERSITY OP I VCAIIPORNIA/ SCIENCES LIBRARY DESCRIPTIVE CATALOGUE OF THE SPECIMENS OP THE ROCKS OF VICTORIA IN THE Jfct&enm, MELBOURNE. GEOLOGY OF VICTORIA. DESCBIPTIVE CATALOGUE OF THE SPECIMENS IN THE atib ^tthnolatywl (MELBOURNE), ILLUSTKATING THE ROCK SYSTEM OF VICTORIA, BY GEORGE H. F. ULRICH, M.E., F.G.S., Lecturer on Mining at the University of Melbourne, and Curator of the Mineral Collection in the Industrial and Technological Museum, Melbourne. MASON, FIRTH & M'CUTCHEON, GENERAL PRINTERS, 51 & 53 FLINDEES LANE WEST. 1875. PUBLIC LIBRARY, MUSEUMS, & NATIONAL GALLERY OF VICTORIA. Incorporated by Act jj> Vic., No. cc civil* trustees : His Honour SIR REDMOND BARRY, President. DAVID CHARTERIS M'ARTHUR, Esq., Vice-Pre- sident. Hon. J. A. MACPHERSON, M.L.A., Treasurer. The Hon. SIR WILLIAM F. STAWELL, Chief Justice. Hon. SIR FRANCIS MURPHY, M.L.C. His Honour Mr. JUSTICE FELLOWS. Hon. SIR JOHN O'SIIANASSY. Hon. SIRC. GAVAN DUFFY, M.L.A. Hon.SiR JAMES M'CuLLOcn, K.C.M.G., M.L.A. Hon. JAMES GOOD ALL FRANCIS. Hon. THOS. TURNER A'BECKETT, M.L.C. Hon. SAMUEL HENRY BINDON. CHARLES E. BRIGHT, Esq. Rev. JOHN I. BLEASDALE, D.D. Hon. SIR WILLIAM H. F. MITCHELL, M.L.C. M. H. IRVING, Esq., M.A. SIR GEORGE VERDON, K.C.M.G., C.B. Hon. CHARLES MACMAHON, M.L.A. Hon. WILLIAM M. K. VALE. Hon. F. S. DOBSON, L.L.D., M.L.C. Hon. JOHN MACGREGOR. Hon. EDWARD LANGTON, M.L.A. Li * INDUSTRIAL & TECHNOLOGICAL MUSEUM, LABORATORIES, >'? m^ With Hornbler (with and with Quartz). -| -Q.2^ g H) 92 V Diorite-Porphj trnblende-Porpl ligoclase-Porph Andesite. Q M O oT a A I 3 |J Iglll II s ! l|l|| ^ ^ Orthoclase- Liebenerite- Porphyry. 1 Q 1 1 1 M t ii .1 ^1.2 i a> i . I "> g ^ 1 **! ^ ' O"<5 PH 1 1 ^fl & a | - g a S3 | |f| I 3 ~ >1 a "S ' oj ^-2 ^: * S a a l3 1 2 1 I ! -.nqnmuo Dill j[nq pun PUB ^q^OJ^ POB H oiiHireqdy -o'jdXjo Assure 6 9 831003 ' 18P [O JiaX I. CRYSTALLINE-GRANULAR SILICATE ROCKS. I. FELDSPAR ROCKS. A. OLDER FELDSPAR ROCKS; OLDER IGNEOUS OR PLUTONIC ROCKS. 1. ROCKS IN WHICH THE PREDOMINATING FELDSPAR IS " ORTHOCLASE." a. QUARTZOSE ORTHOCLASE ROCKS. THE species of rocks of this subdivision represented in the collection are granite (and syenite-granite); granite porphyry (and syenite-granite porphyry), and felsite porphyry. Of these the first and last are the most important, the intermediate species occurring generally only as local modifications, without any defined boundaries within tracts of granite. Granite This rock occupies a considerable portion of the area of the colony, forming larger and smaller isolated tracts and mas- sives, arranged without any system or without following any defined axis a mode of distribution which, according to Mr. Selwyn, seems to indicate the probability of the existence of the rock at no great depth beneath the entire surface of Victoria. Considering their physical features, the granite tracts exhibit each generally one or more high culminating points or massive ridges, from which descend steep rocky spurs, which in their turn gradu- ally merge into low swelling ridges, with here and there higher rounded bosses, and with broad grassy flats between. The higher points and spurs are in most cases quite bare, or support but a poor forest-growth of gum-tree (Eucalyptus), and, as specially characteristic, of she-oak (Casuarina) and honeysuckle (Banksia), which in most of the northern tracts is not even much improved in the lower country at foot, whilst in some of the southern ones (Gippsland) fine timber with dense undergrowth are there prevalent. Wherever the low swelling ridges or the higher rounded bosses are bare of vegetation, and show vertical sections, we observe the peculiar concentric-tabular jointing a special characteristic of B 2 granitic rocks. And isolated blocks of a more fine-grained texture than the rest, or two and three resting one upon the other often in fanciful shapes along the slopes or on the summits of the eminences, prove, by the gentle curvature of their top and resting- planes, to be the less destructible remains of as many concentric- tabular layers, long since disintegrated and removed. The boundaries of the granite areas, i.e., their junctions with sedi- mentary rocks (principally Silurian), are partly very irregular, on account of numberless bends and ramifications, partly singularly well defined, often in straight unbroken lines for long distances (Mount Alexander granite, near Elphinstone, &c.). The influ- ence of the granite upon the bounding rocks will be noticed further on. With few exceptions, all the varieties of granite known and described occur in Victoria, and are represented in the collection in all variations of texture, colour, and mode of composition. In the descriptions following and those given on the labels distinction has been made into binary, ternary, and quaternary granite, which qualifications refer to the number of the essential mineral components of the rock, i.e., whether it contains 2, 3, or 4. For instance, a compound of quartz, feldspar (orthoclase and oligoclase), and mica constituting the typical granite is called common ternary, whilst a replacement of one of these constituents by another mineral, for instance hornblende, tour- maline, talc, epidote, &c., is simply called ternary, and the modification mentioned. If a fourth mineral occurs in the rock, and by its mode of distribution or of association with the other three constituents appears as an essential component, the rock is called quaternary, and the new mineral noticed. It is generally one of the four just mentioned. In the reverse case of one of the three essential components being absent, the rock is called binary, yet with a certain reservation, namely, regarding the binary compound of feldspar (orthoclase and oligoclase) and mica in granular mixture, it is considered nearer allied to syenite, and called mica-syenite, in contradistinction to the typical horn- blende-syenite ; whilst, if the mixture is porphyritic, i.e., repre- sents a feldspathic base, enclosing crystals of orthoclase and mica, it is called after the French minette, being in reality a mica- orthoclase porphyry. Amongst the specimens representing the binary granites in the collection is placed, however, a rather rare one, called greisen, a granular grey rock, composed of light-grey quartz and greyish, yellowish, and greenish mica ; the former in coarse grains strongly predominating. Although the absence of feldspar in this rock renders it inconsistent with the system of classification adopted to place it here, still as it stands in intimate relation to granite, it can be regarded as a granite variety without feldspar. In fact granite graduates into greisen, by a gradual decrease of the feldspar, the intermediate stages of which trans- formation may be considered either as granite poor in feldspar, or as greisen, containing as it were feldspar as an accessory constituent. It is an interesting fact that a very frequent acces- sory mineral of greisen in Europe, viz., cassiterite (tin-ore), in small crystals and grains, has here. (Beechworth) also been found in it, and that the rock-mass from which the specimen in the collection was broken, occurs similarly as there associated with the variety of granite called tin-granite, which is also represented in the collection.* Granite has, in this colony, not as yet been much used as a building stone, owing principally to its being expensive to work on account of its hardness. The variety most abundant throughout Victoria, especially the western gold- fields a medium grained rock, composed of white feldspar, greyish-white quartz, and black mica though not of a very ornamental appearance, forms nevertheless a fine durable building stone, and could be procured at many places in large solid blocks. At Harcourt, near Mount Alexander, extensive quarries have been opened in it, from which very large solid masses have been extracted ; for instance, the square block, many cubic yards in size, covering the grave of Burke and Wills, the explorers, in the Melbourne General Cemetery ; those used for Burke's monument at Castlemaine ; and for Burke and Wills' monument in Mel- bourne, &c. Gellibrand's Hill, section 8, parish of Will-will- Rook, has also furnished good building stone ; for instance, for Prince's Bridge, the old Town Hall, and the Commissioners of Titles Office. A fine ornamental kind a syenite-granite, con- taining red feldspar and greenish hornblende occurs at Gabo Island and other places in Gippsland, that of the former place having been used for the General Post Office, the Custom House, and the Australasian Insurance Company's Offices. With regard to the moot point, whether granite is auriferous, i.e., contains gold impregnated or is traversed by auriferous quartz veins, the workings on the Nuggety Reef, near Maldon, have furnished valuable and interesting data. This celebrated reef, though it does not in fact traverse the granite itself, but terminates against it, is on the contrary, however, traversed by several granite veins.t The lines of contact of the reef-quartz and these * At the Elamore tin mine, near Inverell, New South Wales, " greisen" occurs under quite similar circumstances. t See note accompanying the Geological \ sheet of the Maldon district. 6 intrusive veins are not, however, sharp and defined ; but the quartz becomes, by increasing accession of feldspar and mica, gradually transformed into granite, and within this zone of trans- formation, as it were, specs of gold and of the rare mineral maldonite (an alloy of gold and bismuth) have been found in places quite richly impregnated. In the massive granite no gold has as yet been discovered. The auriferous character of the alluvial and older drifts of gullies and creek valleys, running through granite areas (for instance, at Beech worth, Maldon, Kingower, Moliagul, &c.), can also not be considered as proof of the gold-bearing character of the rock, for the reason that the drift in its composition affords strong evidence of its being in part derived from denuded silurian rocks. In some cases this origin of the drift can be clearly established by the fact that the respective gullies and creeks rise in silurian ranges outside the granite areas ; but even where this latter feature does not obtain, we cannot otherwise explain the presence of silurian material in the drift than by supposing that silurian rocks once existed within the drainage area of such drift-channels. As regards accessory minerals, besides hornblende, black tour- maline ( schorl J, tin-ore and epidote, which constitute special varieties of the rock, the granites of the colony are, in comparison to those of other countries, rather poor. The most frequent are garnet, in fine crystals at Beech worth and Chiltern ; chlorite, in small nests, same localities ; fluorspar, in small patches, poorly crystallised, same localities ; amethyst, finely crystallised in druse- cavities and veins, same localities ; columbite, in small impreg- nated crystals at Maldon ; molybdenite, in small patches and crystals, at Yackandandah, Maldon, Mount Moliagul, &c.; iron- glance, in small plates and scales, at Mount Korong ; iron pyrites, in crystals and grains, generally distributed. It may also be mentioned that those peculiar mineralogical phenomena the so-called enhydros, or water stones, i.e., irregularly polygonal, sharp angular bodies of chalcedony, with hollows inside, con- taining fluid and gas bubbles occur in decomposed granite beneath gold-drift at Beechworth. Felsite Porphyry. Several varieties of this species, as horne- stone porphyry, eurite porphyry, elvanite, quartz porphyry, &c., occur as dykes of sometimes considerable dimensions, and in larger intrusive masses. Of these latter, the best known are Mount Macedon, Dryden's Rock, and the Dandenong Ranges ; a patch in the valley of the Wannon, near Hamilton; and one, the most extensive, in Gippsland, at Buchan, bounding the Snowy River on the west. No minerals of any value have as yet been found in this rock, which hitherto has only proved useful as a pretty good road metal. GRANITE. 1. GRANITE. Common ternary; coarse-grained, and rather feldspathic; contains orthoclase of bluish-white and pale pink colour; also small particles of whitish oligoclase. Excelsior Claim, Reed's Creek, Beechivorth. 2. GRANITE. Common ternary; coarse-grained, and rather feldspathic; contains some oligoclase. One-tree Hill, Beech- ivorth. 3. GRANITE. Common ternary. This specimen is composed of a coarse-grained, rather feldspathic portion in conjunction with a fine-grained rather quartzose one. Neighbourhood of Hensley's Tin-lode, Beechivorth. 4. GRANITE. Common ternary ; rather coarse-grained and feldspathic ; some of the feldspar is oligoclase. Spring Creek, He.echworth. 5. GRANITE. Common ternary; rather coarse-grained; con- tains much oligoclase. Ten chains south of old slaughteryard, Beechivorth. 6. GRANITE. Common ternary; fine-grained and very coarse- grained feldspathic portions mixed, the latter having in places the appearance of graphic-granite; contains some oligoclase. Tail-race, Wooragee Creek, Beechworth. I. GRANITE. Common ternary; medium-grained; quartz rather predominating and forming the largest grains; contains some oligoclase. Mount Alexander. Geological \ sheet 13 N.W. 8. GRANITE. Common ternary ; very coarse-grained and feld- spathic portion in conjunction with fine-grained one. From a vein in massive granite near Dargaris Creek. 9. GRANITE. Common ternary ; very coarse-grained and feld- spathic ; contains some oligoclase. Station Peak, near Geelong. Geological J sheet 20 S.W. 10. GRANITE. Common ternary; medium-grained; in con- junction with black, dense, slightly porphyritic, metamorphic rock (hornfels). Baringhup. Geological \ sheet 14 S.W. II. GRANITE. Common ternary; rather coarse-grained quartz forming the largest grains. Harcourt quarries, near Mount Alexander. Geological^ sheet 13 N.W. 12. GRANITE. Common ternary ; coarse-grained, feldspathic portion in junction with very fine-grained quartzose one ; the 8 former shows some oligoclase. Station Peak, near Geelong. Geological J sheet 20 S. W. 13. GRANITE. Common ternary ; coarse and fine-grained granite portions parted by a seam of fine-granular quartz. Station Peak, near Geelong. Geological J sheet 20 S. W. 14. GRANITE. Common ternary ; rather fine-grained ; encloses large patches of orthoclase. Dog Rocks, near Geelong. 15. GRANITE. Common ternary ; rather fine-grained, with larger patches of feldspar and quartz. Dog Rocks, near Geelong. 16. GRANITE. Common ternary; medium-grained; contains some oligoclase. Mill-road, four miles from Beechworth. 17. GRANITE. Common ternary; fine-grained, with a slightly porphyritic aspect, due to enclosed larger patches of feldspar, smoky quartz, and black mica. Newtown quarries, Beechivorth. 18. GRANITE. Common ternary, with but little mica ; very coarse-grained ; feldspar slightly decomposed. Saddle in range east of Pound Creek, Beechworth. 19. GRANITE. Common ternary ; very coarse-grained and feldspathic ; mica of black and white colour ; encloses patches of schorl (black tourmaline). From a vein in silurian rocks near top of Mount Tarrangower. Geological J sheet 14 S.W. 20. GRANITE. Common ternary; very fine-grained portions poor in mica, mixed with highly micaceous ones, and enclosing large patches and crystals of orthoclase. Ingletvood. 21. GRANITE. Same as No. 20. Inglewood. 22. GRANITE. Common ternary ; coarse-grained portion in conjunction with fine-grained one ; encloses a large patch of crystallised schorl (black tourmaline) ; feldspar slightly decom- posed. From near Mount Tarrangower. Geological |- sheet HS.W. 23. GRANITE. Common ternary ; coarse-grained and rather feldspathic; feldspar slightly affected by decomposition. Mount Xorong. 24. GRANITE. Common ternary coarse-grained ; quartz slightly predominating and forming the larger grains. Mount Kingower. 25. GRANITE. Common ternary ; very coarse-grained and traversed by veins of chalcedony. Spring Creek, Beechworth. 26. GRANITE. Common ternary; fine-grained. Spring Creek, Beechworth. 27. GRANITE. Common ternary, but poor in mica ; medium grained, and somewhat affected by decomposition ; rusty colour, due to percolation of ferruginous waters. Mount Beckwith. 28. GRANITE. Common ternary; coarse-grained and highly 9 -quartzose; portions consist of nearly pure quartz. North side of Pound Creek, Beechworth. 29. GRANITE. Common ternary, but very poor in quartz ; structure imperfectly laminated, resembling that of gneiss ; feld- spar slightly affected by decomposition. Pennyweight Flat, Beechworth. 30. GRANITE. Common ternary, but very poor in mica ; -quartz of a dark smoky colour; contains a considerable per- centage of yellowish-coloured oligoclase. Mill-road, three miles from Beechworth. 31. GRANITE. Common ternary; medium-grained, and rather feldspathic. The peculiar mode of the distribution of the black mica imparts to it a porphyritic aspect. Mount Korong. 32. GRANITE. -Common ternary, but very poor in mica ; slightly affected by decomposition. Mount Beckwith. 33. GRANITE. Common ternary ; fine-grained and rather micaceous. Mount Beckwith. 34. GRANITE. Common ternary ; fine-grained and very micaceous. Mount Kingower. 35. GRANITE. Common ternary ; main mass rather fine- grained, and rendered porphyritic by larger crystals of orthoclase and patches of quartz ; feldspar rather granular, and devoid of lustre on accout of partial decomposition. Inglcwood. 36. GRANITE Common ternary ; rather fine-grained and poor in mica ; larger patches of feldspar impart to it a mottled appearance. Mount Beckwith. 37. GRANITE. Common ternary ; black mica strikingly predominating; medium-grained. Excelsior Claim, Reid's Creek, Beechworth. 38. GRANITE. Common ternary ; rather fine-grained ; mica scattered in small quantity. Bendigo. 39. GRANITE. Common ternary ; rather feldspathic ; medium- grained; occurs as pebbles in upper palaeozoic conglomerate. N.E. ofMia-mia. Geological \ sheet N.E. Note 40. 40. GRANITE. Common ternary, but very poor in mica, flesh- -coloured orthoclase predominating ; very coarse-grained ; would form a handsome building stone. Tail-race, Wooragee Creek, Beechworth. 41. GRANITE. Common ternary, but poor in mica; very coarse-grained and feldspathic ; feldspar of fine flesh-colour ; bears a strong resemblance to No. 40. Gabo Island. 42. GRANITE. Common ternary ; contains black and white mica ; coarse-grained. Pyramid Rock, Phillip Island. 43. GRANITE. Common ternary; flesh-coloured orthoclase greatly predominating ; rather poor in quartz ; mica black, 10 green, and white ; encloses small patches of chlorite ; very- coarse-grained. Gabo Island. 44. GRANITE. Common ternary, but poor in mica, mottled white and pink coloured orthoclase predominating ; medium- grained. Mount Beckwith. 45. GRANITE. Common ternary ; rather feldspathic, some of the feldspar being oligoclase ; medium-grained. Inglewood. 46. GRANITE. Common ternary, but very poor in mica ; one portion rather feldspathic and coloured brownish by ferruginous infiltrations ; in the remainder the black spots appear to be due to manganiferous brown iron-ore ; medium-grained. Mount Beckwith. 47. GRANITE. Common ternary ; in part very micaceous ; rather fine-grained. Mount Beckwith. 48. GRANITE. Common ternary; rather feldspathic ; medium- grained. Eastern slope of Mount Baw-baw, near Walkalla. 49. GRANITE. Common ternary ; a rather fine and even- grained mixture of white feldspar, quartz, and white mica, with a few small patches of black tourmaline (schorl), and a few grains of brown garnet ; some of the feldspar is triclinic (albite ?) ; structure of the rock apparently tabular. Mount Korong. 50. GRANITE. Common ternary, but rather poor in mica ; medium-grained ; encloses large patches of quartz and orthoclase. From between Violet Town and Seymour. 51. GRANITE. Common ternary ; medium-grained ; encloses larger patches of quartz. From between Violet Town and Seymour. 52. GRANITE. Common ternary, but poor in mica, feldspar predominating ; very fine-grained. Mount Beckivith. 53. GRANITE. Common ternary ; very fine-grained ; consists of a rather decomposed highly feldspathic base enclosing larger patches of greenish- white mica, Tail-race, Wooragee Creel', Beechworth, 54. GRANITE. Common ternary, but poor in mica ; fine- grained very feldspathic base, rendered in part porphyritic by larger patches of quartz. Mount Beckwith. 55. GRANITE. Common ternary, but poor in mica; rather fine-grained. Mount Beckvrith. 56. GRANITE. Common ternary, but very poor in mica ; fine- grained ; portion of a vein of coarse-grained granite containing oligoclase visible along one edge. Eumemmering Creek, Robinson's Station. 57. GRANITE. Common ternary, rather feldspathic; very 11 fine-grained. Back track to Wooragee, Beechworth. 58. GRANITE. Common ternary ; fine-granular mixture of orthoclase, some oligoclase, white mica, and quartz. Neighbour- hood of Ballarat. 59. GRANITE. Common ternary ; quartzose and very mica- ceous in part ; extremely fine-grained. From close to boundary of lower silurian rocks, Loddon River, near Mount Tarrangower. 60. GRANITE. Common ternary ; very micaceous and fine- grained. From close to boundary of lower silurian rocks, Loddon River, near Baringhup. Geological | sheet 14 S.W. 61. GRANITITE. Common ternary; coarse-grained; contains quartz, much greenish-white oligoclase, flesh-coloured orthoclase, and little black mica. Occurs as pebbles in upper palaeozoic conglomerate north-east of Mia-mia. Geological |- - sheet N.E. Xote 40. 62. GRANITITE. Common ternary ; very rich in greyish-green oligoclase, easily distinguishable from the flesh-coloured orthoclase ; medium-grained ; would form a handsome building stone. Pyramid Rock, Phillip Island. 63. GRANITITE. Common ternary ; fine-grained base, contain- ing much oligoclase, rendered porphyritic by patches of black mica and larger crystals and grains of flesh-coloured orthoclase and smoky quartz. Grampians. 64. GNEISS-GRANITE. Common ternary ; medium-grained ; very micaceous, the peculiar mode of distribution of the mica imparting to it a gneissose texture. BucknalUs Station, near Carisbrook. 65. GNEISS-GRANITE. Common ternary; fine-grained; very micaceous; the peculiar mode of distribution of the mica producing a gneissose texture. Part of the specimen in which this texture is absent is rendered porphyritic by larger crystals of orthoclase, and contains some oligoclase. Bendigo. 66. TIN-GRANITE. Common ternary, but very poor in mica ; coarse-grained ; contains cassiterite (tin-ore) and copper and arsenical pyrites finely impregnated. Gimblet's Tin locality, Beechworth. 67. TIN-GRANITE. Common ternary ; fine-grained; very poor in mica and rich in oligoclase; contains small grains and crystals of cassiterite (tin-ore) and arsenical and copper pryrites disseminated through the mass, and is irregularly traversed by thin quartzose veins full of the same minerals. Gimblet's Tin locality, Beechworth. 68. TIN-GRANITE. Common ternary ; rich in silvery-white mica ; medium-grained ;, contains grains of cassiterite scattered 12 through the mass; rather friable on account of partial decompo- sition of the feldspar. Hensley's Tin-lode, Beechworth. 69. GREISEN. Binary; composed of granular quartz with patches of white and greenish-grey mica ; contains scattered grains of tin-ore. (See introductory remarks under Granite.) Neighbourhood of Hensley's Tin-lode, Beechworth. 70. HALF-GRANITE (Aplite). Binary ; quartz and orthoclase ; coarsely porphyritic. The orthoclase crystals are twins of the Baveno type. From a dyke in common ternary granite near Bradford. Geological J sheet 14 N.W. 71. HALF-GRANITE (Aplite). Binary; quartz and orthoclase ; coarsely porphyritic. The orthoclase crystals, though rather imperfect, appear, like in No. 69, to be twins of the Baveno type. Station Peak, near Geelong. Geological -|- sheet 20 S. W. 72. HALF-GRANITE (Aplite). Binary ; quartz and orthoclase, the former greatly predominating, the latter more or less decomposed. The peculiar layer-like mode of distribution of the feldspar produces a rather imperfectly laminated structure. Back track to Wooragee, Beechworth. 73. HALF-GRANITE (Aplite). Binary. This specimen consists of a porphyritic portion a white fine granular feldspathic base enclosing quartz grains which graduates into a dense intimate mixture of much quartz and some feldspar, conforming to felsite, or so-called "haelleflinta." Breakneck track, Reid's Creek, Beechworth. 74. HALF-GRANITE (Aplite). Binary; medium-grained; an even mixture of quartz and white orthoclase, rendered porphyritic by larger grains and crystals of orthoclase of a light flesh-colour. From a dyke in common ternary granite, Mount Alexander. 75. HALF-GRANITE (Aplite). Binary; quartz and orthoclase with a few scattered scales of mica ; the feldspar slightly affected by decomposition. Mount Beckwith. 76. HALF-GRANITE (Aplite). Binary ; quartz and orthoclase, the latter slightly predominating; rather fine-grained. Mount Beckwith. 77. HALF-GRANITE (Aplite). rBinary; fine-granular rather feldspathic base, composed of quartz and orthoclase, rendered porphyritic by small patches of quartz and a few scales of mica. Mount Beckwith. 78. HALF-GRANITE ( Aplite). Binary ; quartz and orthoclase with a few scales of mica ; rather fine grained. Mount Beckwith. 79. HALF-GRANITE (Aplite). Binary; very fine-grained uniform mixture of quartz and feldspar, the latter rather 13 predominating ; approaches felsite in appearance. RiddelVs Creek, near Mount Macedon. 80. HALF-GRANITE (Aplite). Binary ; fine-grained mixture of quartz and orthoclase with larger patches of both minerals interspersed. Loddon River. 81. HALF-GRANITE (Aplite). Binary; very fine-grained mixture of quartz and orthoclase. From the " Hanging Rock" dyke, near Heathcote. (Geological Note by Mr. Norman Taylor. This dyke, which lies to the westward of the Heathcote township, is in places of an ordinary granite character ; in others it passes into eurite. The most prevailing colour is of a light-brown passing into light-green. In width it varies from two to five chains, and is traceable for four miles south of the Kyneton road-cutting, where it appears to pass into a thin granite dyke, accompanied by greenstone. It is extensively used in Heathcote both for building and kerbiug, the harder varieties being well adapted for these purposes. It has also been used for making filters, or " drip-stones." The dyke has, probably, some connection with one occurring in the area of Geological J sheet 51 S.W.) 82. HALF-GRANITE (Aplite). Binary ; fine-grained mixture of quartz and principally orthoclase. Button Grange, near Mount Alexander. Geological sheet 15 N. W. 83. HALF-GRANITE (Aplite). Binary ; very fine-grained mixture of quartz and orthoclase. Dyke under Mount Ida Hotel, Heathcote. 84. HALF-GRANITE (Aplite). Binary; much decomposed feldspar and greenish mica. Pyrenees. 85. HALF-GRANITE (Aplite). Binary; quite decomposed feldspar and quartz; medium-grained. Pennyweight Flat, Beechworth. 86. EPIDOTE-GRANITE. Ternary; flesh-coloured orthoclase, green " epidote" (pistacite), and some quartz ; medium-grained. Head of Nuggety Gully, near Talbot. 87. TOURMALINE-GRANITE. Quaternary; a crystalline, fine- granular mixture of white feldspar, quartz, white mica, and black tourmaline (schorl), with a few grains of brown garnet ; some of the feldspar is triclinic (albite ?) ; structure of the rock apparently tabular. Resembles No. 49, but contains more tourmaline. Bendigo District. 88. SYENITE-GRANITE. Ternary; consists of flesh-coloured orthoclase, hornblende, and quartz ; medium-grained. A fine ornamental building stone, but expensive to work. Used in the General Post Office, the Australasian Insurance Company's H offices, for gravestones, &c. Gabo Island. 89. SYENITE-GRANITE. Ternary; medium-grained; composed of flesh-coloured orthoclase, some greenish-white oligoclase, hornblende, and quartz. Would form a fine ornamental building stone, though, like No. 88, expensive to work. Gippsland. 90. SYENITE-GRANITE. Ternary; fine-grained; composed of feldspar, quartz, and hornblende ; some of the feldspar appears to be oligoclase. From a dyke in Van der Luffs paddock, near Heathcote. 91. SYENITE-GRANITE. Ternary; a fine-grained base, com- posed of feldspar, quartz, and hornblende, rendered porphyritic by irregular-sized patches and crystals of feldspar. From a dyke in south-west corner of Geological -| sheet 51 S. W. 92. SYENITE-GRANITE. Quaternary ; brecciated-looking mix- ture of portions of common ternary, coarse and fine-grained granite, rendered porphyritic by crystals of black "hornblende;" a considerable percentage of the feldspar showing a light-greenish colour is "oligoclase." Mount Kingovjer. 93. SYENITE-GRANITE. Quaternary ; medium-grained, com- mon ternary granite with abundance of " oligoclase," rendered porphyritic by largish crystals of black " hornblende." Mount Kingower. 94. SYENITE-GRANITE. Quaternary ; medium-grained com- mon ternary granite base, rendered porphyritic by crystals of black " hornblende," and coloured brownish-red by hydrous oxide of iron ; part of the feldspar appears to be " oligoclase." Mount Beckwith. 95. SYENITE-GRANITE. Quaternary ; fine-grained common ternary granite base, rendered porphyritic by crystals of black " hornblende" and of both "orthoclase" and " oligoclase." Bendigo. 96. DECOMPOSED GRANITE (Kaolin Rock). Feldspar entirely decomposed to kaolinite, through which quartz grains are sparingly distributed ; mica completely removed ; valuable for china manufacture. Deep Creek, near Bulla. Geological J sheet 7 S.E. 97. DECOMPOSED GRANITE (Kaolin Rock). Same as No. 96. Mount Kingower. 15 GRANITE PORPHYRY. This species, which stands intermediate between granite and felsite porphyry, is represented in the collection by but a few and not very characteristic specimens. Several very fine and characteristic ones are contained, however, in the collection of rocks from New South Wales. 98. GKANITE PORPHYRY. Extremely fine-grained binary base, composed of feldspar and quartz, full of crystals of orthoclase and quartz ; those of the latter representing mostly the double hexagonal pyramid, with no, or but occasional very small, planes of the hexagonal prism. Back Creek, east of Spring Plains. Geological J sheet 51 S.W. 99. GRANITE PORPHYRY. Very fine-grained, common ternary granite base, showing imperfect crystals and patches of quartz, and accumulations of scales of greyish-green mica ; encloses also pseudomorphs of brown iron ore after iron pyrites. M'Intyre Diggings. 100. GRANITE PORPHYRY. Common ternary, very fine-grained granite base, poor in mica, with larger and smaller crystals of orthoclase, oligoclase, and dark-coloured quartz. One-tree Hill, Beechwortfi. 101. GRANITE PORPHYRY. Common ternary, very fine-grained granite base, with crystals of quartz, orthoclase, and mica, the latter rather prominent. Brewery Springs, near Maldon. 102. GRANITE PORPHYRY. Extremely fine-grained, nearly dense, binary granite base, composed of feldspar and quartz, enclosing crystals of orthoclase and small granular black patches, consisting of scales of black mica. North-east of Baynton. Geological J sheet 51 S.W. 103. SYENITE-GRANITE PORPHYRY. Fine-grained, common ternary granite base, enclosing crystals of hornblende and large crystals of orthoclase. West of Lancefield-road, south of parish of Baynton. Geological -J sheet 5 N. W. 104. SYENITE-GRANITE PORPHYRY. Very fine-grained, qua- ternary, rather quartzose, granite base (quartz, mica, hornblende, and orthoclase), with large crystals of hornblende and feldspar ; the latter consisting of both orthoclase and oligoclase. Mount Kingower. 105. SYENITE-GRANITE PORPHYRY. Fine-grained, quaternary granite base (feldspar, quartz, mica, and hornblende), enclosing large crystals of hornblende, mica, and feldspar j some of which latter appears to be oligoclase. Heathcote. 1C 106. SYENITE-GRANITE PORPHYRY. Fine-grained syenite- granite base (orthoclase, quartz, and hornblende), with larger crystals of feldspar and hornblende. From a dyke at south-ivest corner of Geological J sheet 51 S. W. FELSITE-FELSITE PORPHYRY. Of this species the collection contains a number of fine characteristic specimens, representing most of the known varieties. Some of these varieties are called by various names, which have been noted both on the descriptive labels and in the sequel. 107. FELSITE (Feldstone, Elvanite.) Dense siliceo-feldspathic rock. From between Violet Town and Seymour. 108. FELSITE (Feldstone, Elvanite). Dense siliceo-feldspathic rock, similar to 107. From a hill 12 miles north of Sandhurst. 109. FELSITE (Feldstone, Elvanite). Same as 108. 110. FELSITE (Feldstone, Elvanite). Extremely fine-grained, nearly dense rock, with imperfect slaty cleavage, consisting of an intimate mixture of quartz and feldspar, of which the former greatly predominates. The black markings appear to be of a dendritic character, caused by oxide of manganese. From a dyke running along Swiper's Reef, Maldon. 111. FELSITE (Feldstone, Elvanite). Siliceo-feldspathic rock ; rather porous. Similar to 107 and 108. Heathcote. 112. FELSITE. A light greenish-coloured felsitic rock, traversed and rendered breccia-like by innumerable veins and nests of quartz From a dyke. in granite, Spring Creek, BeechwortJi. 113. FELSITE PORPHYRY (Feldstone Porphyry, Eurite Por- phyry, Elvanite). Yellowish-white felsitic base, enclosing rather small crystals of quartz (mostly perfect double hexagonal pyramids) and orthoclase. Bank of the Yarra River, betiveen Prince's Bridge and the Botanical Gardens. Geological \ sheet 1 S.E. 114. FELSITE PORPHYRY (Feldstone Porphyry, Elvanite). Yellowish-white, rather dull felsitic base, with crystals of orthoclase, hornblende, patches of greenish-white mica, and occa- sional grains of quartz. Gippsland. 115. FELSITE PORPHYRY (Eurite Porphyry, Quartz Porphyry, Elvanite). Dense, white, apparently pure feldspar base, enclos- ing grains and crystals of quartz. This rock has some resem- blance to the species " granulite" or " leptynite." Dunolly. 116. FELSITE PORPHYRY (Feldstone Porphyry, Quartz Por- phyry, Elvanite). Whitish, rather dull felsitic base, with grains 17 crystals of quartz ; appears to be indistinctly laminated ; ^the black spots are apparently, as on No. 110, of a dendritic ch aracter. Kingower. 117. FELSITE PORPHYRY (Feldstone Porphyry). Bluish-grey, very fine-granular, siliceo-feldspathic base, with rather scattered crystals of orthoclase and quartz. Loddon River, near Maldon. 118. FELSITE PORPHYRY (Hornstone Porphyry). Dense, brown, hornstorie-like base, densely impregnated with crystals of orthoclase and grains of quartz ; a few scattered mica scales and .grains of almandine garnet are also observable in places. .Kingower. 119. FELSITE PORPHYRY (Hornstone Porphyry). Dense, brown base, with rather small crystals of reddish orthoclase and grains and crystals of dark-coloured quartz. From between M'lvor and Sandhurst. 120. FELSITE PORPHYRY (Hornstone Porphyry). Dense greenish-grey, hornstone-like base, enclosing crystals of flesh- coloured orthoclase and grains of quartz. Upper Wannon .Falls. 121. FELSITE PORPHYRY (Hornstone Porphyry). Base greyish- black ; otherwise same as 120. Upper Wannon Falls. 122. FELSITE PORPHYRY. Very fine-granular, greyish-black base, with crystals of feldspar, some of which appear to be triclinic. West of Mount Disappointment, Upper Plenty River geological sheet 3 N.E. 123. FELSITE PORPHYRY (Hornstone Porphyry). Dense, 'black, hornstone-like, brecciated- looking base, enclosing grains of quartz and in less quantity small crystals of flesh-coloured orthoclase. Dandenong Ranges. 124. FELSITE PORPHYRY. Dense, yellowish-grey base, densely impregnated with crystals of orthoclase and grains of quartz; -slightly affected by decomposition around the margin. Bendigc. 125. FELSITE PORPHYRY (Feldstone Porphyry, Quartz Porphyry, Elvanite). -Very fine-granular, siliceo-feldspathic base, with crystals of quartz (frequently perfect double hexagonal pyramids) and a few scattered crystals of feldspar. M'Intyre. 126. FELSITE PORPHYRY (Feldstone Porphyry, Elvanite). Greenish-white, siliceo-feldspathic base, with crystals of feldspar and grains of quartz ; the former affected by decomposition. From betiveen Violet Town and Seymour. 127. FELSITE PORPHYRY (Feldstone Porphyry, Elvanite). The same as 126. 128. FELSITE PORPHYRY (Feldstone Porphyry, Elvanite). Dull yellowish-white, siliceo-feldspathic base, with scattered 18 scales of greenish-white mica, thin needles of hornblende, and a few quartz grains ; affected by decomposition round the margin. Loddon River. 129. FELSITE PORPHYRY (Elvanite). Very fine granular, siliceo-feldspathic base, full of grains and crystals of quartz, orthoclase, and hornblende. From between Violet Tenon and Seymour. b. QTJARTZLESS ORTHOCLASE ROCKS. Rocks belonging under this head, in which quartz does not form an essential component, though it may occasionally occur as an accessory, are apparently very rare in Victoria, and the collection contains only three specimens, representing the species " syenite" and " syenite porphyry" (quartzless orthoclase porphyry). 130. SYENITE. Medium-grained mixture of flesh-coloured orthoclase and greenish-black hornblende, with scattered particles of chlorite and a few quartz grains. Head of Nuggety Gully, Talbot. 131. SYENITE. Fine-grained mixture of much flesh-coloured orthoclase, little hornblende, epidote, and a few scales of mica and grains of quartz. Traversed by seams of dense green epidote (pistacite). Omeo-road, Gippsland. 132. SYENITE PORPHYRY (Quartzless Orthoclase Porphyry). Fine-granular, syenitic base (apparently composed of hornblende and feldspar), with crystals of very glassy-looking orthoclase. Brock's Monument, north-east of Mount Macedon. Geological \ sheet 2. ROCKS IN WHICH THE PREDOMINATING FELDSPAK IS TRICLINIC (PLAGIOCLASE). . OLIGOCLASE ROCKS. DIORITE AND ALLIED ROCKS. The rocks of this class, essentially compounds of oligoclase and hornblende, occasionally associated with quartz and mica, are also known under the general term " greenstone" " horn- blendic greenstone" in contradistinction to the " augitic green- stone," "Diabase," not yet observed in Victoria. They occur in our colony mostly as dykes, varying from a few to several 19 hundred feet in thickness, traversing upper silurian rocks, and are represented in the collection in nearly all the varieties of texture and mineral composition mentioned in text-books. These dykes are, as mining features, of special interest and importance, because they have nearly, as a rule, been found impregnated with auriferous pyrites, and traversed by or associated, either on the hanging or foot-walls, or on both walls, with auriferous quartz veins, partly regular, partly quite irregular, in course, extent, and richness. In fact, it maybe affirmed that by far the greater quantity of the quartz-gold produced by the goldfields occupied by upper silurian rocks, is derived from such diorite dykes. As- some of the dykes celebrated in this respect may be mentioned the large dyke of the Morning Star Hill, Wood's Point ; that of the Loch Fyne Company, near Matlock ; at Gaffney's Creek those of the Eldorado and Wallaby companies ; and a very important one which has been opened for four to five miles in length, and has been for years successfully worked by the Rose of Denmark Company at its northern, and by the Castle Reef and Al companies at its southern end, with numerous rich claims intermediate. In Gippsland we have rich dykes at Donnelly's Creek ; and at Walhalla, besides that of the Longfellow's- Company, the dyke of the celebrated Cohen's Reef, perhaps the richest one in the colony. Some of the specimens from it shown, in the collection, represent the variety " diorite aphanite," and can hardly be distinguished from those derived from the dyke of the Rose of Denmark Company, Gaffney' Creek. At Crossover Creek, North Gippsland, the dyke of the Albion Company is interesting, on account of its highly micaceous- character, and the clear evidence it affords of the favourable influence of the dyke upon the gold-bearing character of the reefs traversing it at right angles to its strike. For whilst these reefs are but very poorly auriferous in the upper silurian slate, into which they continue on either side, they become even richly- gold-bearing throughout the width of the dyke (about 90 feet). Another place where a great number of diorite dykes occur, most of which have proved auriferous, is Alexandra ; but they are there very much decomposed a feature shown by most dykes, in a stronger or less degree, to varying sometimes considerable depths- beneath the surface. With regard to the question whether the strike or direction and angle of dip of dykes, texture or mode of com- position of the rock i.e., whether coarse or fine-grained, or the predominance of either feldspar or hornblende have any bearing upon the auriferous character of the traversing or associated quartz veins, no conclusive observations have as yet been made.. c 2 20 Judging from a number of well-known dykes, it seems, however, as if neither of these features has any influence in this respect. Whilst, for instance, the dyke of Cohen's Reef, Walhalla, and the extensive one at Gaffney's Creek, above noticed, are for the greater part of an aphanitic, highly feldspathic character, the equally rich dykes of the Morning Star Hill, Loch Fyne, Eldorado, Wallaby, &c., are coarse-granular and highly horn- biendic, and their strikes and dips are also different. There is another feature in connection with some of these dykes which deserves special notice namely, that they show in strike arid dip great changes both in texture and composition. For instance, the extensive dyke of Gaffney's Creek, and, in a less degree, the dyke of Cohen's Reef, are in some parts distinctly crystalline-granular, i.e., show a granitic texture with triclinic feldspar and hornblende plainly perceptible, whilst for the greater part opened they are micro-crystalline-granular, apparently quite dense, light greenish-grey feldstone-like with neither horn- blende nor feldspar recognisable. In fact, if it was not for the occasional changes in texture and composition just mentioned, the rock would sooner be taken to be a true feldstone than as belonging to diorite, representing the variety feldspathic diorite- aphanite. A fine illustration of both a textural and mineralogi- cal change combined exhibits the dyke on which the Thomson River copper-mine has been opened. The copper-ore-bearing part is here a coarse-granular, highly hornblendic diorite in fact, nearly pure hornblende rock in places which forms " shoot- like," the northern termination of the dyke, whilst southward in strike it changes within a very short distance, through fine- granular to a nearly dense, highly feldspathic aphanite, closely resembling the rock of the Cohen's Reef and GafFney's Creek dykes, just spoken of. 133. DIORITE. Granular mixture of hornblende and oligo- clase, with scattered quartz grains. Near south-east corner of section 15, parish of Metcalf. Geological J sheet 13 S.E. 134. DIORITE. Rather coarse-granular and hornblendic. Eastern side of right-hand branch of Stringer's Creek, Walhalla. 135. DIORITE. Coarse-granular and highly hornblendic; forms the northern termination of a strong dyke, and represents the "lodestone" of the Thomson River copper mine, being in parts densely impregnated with copper and iron-pyrites, and traversed by irregular larger and smaller veins of these ores, intimately mixed. Southward in strike it changes to a dense, feldspathic aphanite (see No. 150). Thomson River copper mine, near Walhalla, North Gippsland. 21 136. DIORITE. Crystalline-granular, medium-grained; strongly impregnated with iron pyrites. Dyke of the Eureka mine, about three-quarters of a mile east of Wal/ialla,, North Gippsland. 137. DIORITE. Medium-grained, and rendered slightly por- phyritic by small patches of quartz and crystals of triclinic feldspar and hornblende ; impregnated with iron and magnetic pyrites. East of Lancefield. Geological % sheet 5 S.E. MR. NORMAN TAYLOR'S NOTE. The greenstone (diorite) com- posing the range to the east of the parish of Lancefield is very variable in its lithological character. Mount William, at the extreme northern and highest part of the range, and at its junction with the Great Dividing Range, is composed of a very hard, dark- greenish black, dense (aphanitic) rock, closely resembling a basalt, and with a metallic ring when struck, like " clinkstone," passing southwards to a lighter green, hard rock, with crystals of triclinic feldspar, sometimes having the appearance of a greenish-white rock, with black, dendritic (horn- blendic) markings. This stone (see building-stone Cubes R, 30, 31, 32), were it not for its extreme hardness, and consequent difficulty and expense in quarrying and working up, would make a very handsome stone for building or ornamental purposes. Further south it passes into a black, highly crystalline, horn- blendic rock, and then again to a dark-green, dense rock with specks of iron pyrites. Near the centre of this range (see \ sheet 5 S.E.) is a fault, cutting off the greenstone. Its place is supplied by a very rich and heavy brown iron -ore or brown hematite (see Mineral Collection, National Museum, case 13, No. 36). The greenstone weathers externally to a rusty-brown colour. The unfossiliferous silurian shales resting as small outliers on the top of this greenstone range (probably the remains of a denudation of the formation up-heaved by it), and also the contiguous rocks on the west side, are all highly metamorphosed, the shales being converted into a hard jaspery porcelanite. About a mile north-east of Mount William is the site (locally called " The Native Tomahawk Quarries") whence the aboriginal tribes of the neighbouring districts have procured the greenstone used by them for making tomahawks. From the amount of broken stone covering a large area, this quarry must have been in use for a very lengthened period. 138. DIORITE. Fine-granular; contains scattered specks of iron pyrites. Loddon River. 139. DIORITE. Fine-granular and very even-grained. Lod- don River. 140. DIORITE. Fine-granular and slightly porous; affected 22 by decomposition. Loddon River. 141. DIORITE. Fine-granular, highly feldspathic, much de- composed ; traversed by a small quartz vein, and slightly impregnated with crystals of iron pyrites. From a dyke traversed with auriferous quartz veins, South Longfellow's Company's ground, near Walhalla, North Gippsland. 142. DIORITE. Fine-granular; strongly affected by decom- position ; full of patches and irregular veins of partly crystallised iron pyrites. From t/ie gold-bearing dyke of Hunt's Claim, Ga/ney's .Creek. 143. DIORITE. Granular; medium-grained; strongly affected by decomposition. From the gold-bearing dyke, the so-called " Cohen's Reef," Walhalla, North Gippsland. 144. MiCA-DiORiTE. A rather coarse-granular mixture of somewhat gneissose texture of oligoclase, mica, and quartz ; conform^ in composition to the rock described as " kersantite," occurring in the Vosges mountains, France. Van der Luffs paddock, near HeatJicote. 145. MICA-DIORITE (Mica-Porphyrite). Fine-granular, feld- spathic, apparently chloritic and somewhat decomposed diorite base, rendered porphyritic by hexagonal plates' of brownish-black mica and a few crystals of feldspar and hornblende ; strongly impregnated with grains of copper and iron pyrites ; conforms to the rock described as '* kersanton," occurring in Brittany, France. From a dyke traversed by highly auriferous quartz veins at Crossover Creek, North Gippsland. 146. DIORITE- APHANITE. An extremely fine-grained, appa- rently dense diorite, rendered micro-porphyritic by very slender prismatic crystals of hornblende. Den Hills, near Montham. 147. DIORITE- APHANITE. Apparently dense homogeneous base, rendered slightly porphyritic by crystals of triclinic feldspar {oligoclase) ; contains scattered specks of copper pyrites. Dyke under Mount Ida Hotel, Heathcote. 148. DIORITE- APHANITE. Microcrystalline-granular ; quite dense and compact looking ; highly feldspathic ; encloses crystals of iron pyrites, and shows on one side a crystalline coating of bitterspar, in which is embedded a small speck of gold. From the auriferous dyke of the A 1 Company, Castle Reef, Raspberry Creek. 149. DIORITE- APHANITE. Microcrystalline-granular ; quite dense and compact looking ; highly feldspathic ; traversed by veins of auriferous quartz and arsenical pyrites, and strongly impregnated with crystals of iron pyrites and slender prismatic crystals of arsenical pyrites. From the auriferous dyke, the so-called 23 f( Cohen's Reef" Walhalla Company 's mine, Walhalla. 150. DiORiTE-ArHANiTE. Microcrystalline-granular ; appa- rently dense, felsite-like ; highly feldspathic, and rather calcareous ; traversed by quartz veins. Forms the modification southward in strike of the hornblendic, cupriferous, diorite dyke of t/ie Tlwmson River copper mine, Walhalla (see No. 135). 151. DIORITE PORPHYRY (Aphanite Porphyry). Microcrys- talline-granular ; aphanitic diorite base, densely charged with small crystals of white triclinic feldspar (oligoclase *?) ; a few scattered needles of black hornblende are also observable. "Hanging Rock" Jyle, near Heathcote. Geological | sheet 51 N.W. 152. DIORITE PORPHYRY (Aphanite Porphyry). Dense, greenish-black aphanite base, with crystals of whitish oligoclase, and scattered, small patches of very fine-scaly mica. North-east of Baynton, county of Dalhousie. 153. DIORITE PORPHYRY. Finely crystalline-granular, greyish diorite base, with crystals of white oligoclase and black horn- blende. Dyke two miles north of the Green Hill, near Malmsbury. 154. DIORITE PORPHYRY (Aphanite Porphyry). Dense, greenish-black aphanite base, with crystals of triclinic feldspar and grains of quartz. Loddon River. 155. DIORITE PORPHYRY. Finely granular, micaceous diorite base, with crystals of triclinic feldspar and hornblende ; strongly affected by decomposition. Intrusive patch near Tarilta. Geological J sheet, 16 N.E. Geological Note. -This specimen comes from a peculiar intrusive mass of rock, several acres in extent, that, in most places where exposed, consists of diorite (pinkish triclinic feldspar and black hornblende), but assumes at others granitic, syenitic, porphyritic, and brecciated characters. Thus at its junction with the black graptolite slates of the neigh- bourhood, where several small faults have been traced (see sketch on geological sheet 15 N.E.), the rock bears the character of a porphyry, more or less decomposed (specimen 155) ; whilst at another place, scarcely four chains off, the accession of black mica and some quartz renders the rather decomposed rock undistinguishable from decomposing granite ; and from one of the small shafts sunk for the purpose of examination, specimens of u epidosite" (see specimen 239) were also obtained. In small cavities of the porphyritic variety, crystals of " albite," associated with abnormally formed quartz crystals, occur, and it was there- fore probable that the feldspar entering into the composition of the rock might also be " albite," though the absence of the characteristic twin-striation on its cleavage planes gives it all the -appearance of " orthoclase." The following results of an analysis 24 by Mr. J. Cosmo Newbery, viz. Silica, 6 7 '70 ; alumina, 20 '50 ; sesquioxide of iron, traces ; lime, traces ; magnesia, traces ;. potassa, traces ; soda, 10 '00 proves it, however, clearly to be " albite," and the rock is therefore a diorite according to recent views on petrographical classification. The adjoining fossiliferous strata are not, or but very slightly, altered, and hand-specimens can easily be obtained, of which one half (of a specimen) consists of black slate, with well-preserved graptolites, and the other of the porphyritic variety of the intrusive rock. The brecciated variety, apparently a mixture of chips of silurian rock and of the dioritic paste, occurs only here and there along the boundary of the formations. PORPHYRITE AND ALLIED ROCKS. 156. MICA-PORPHYRITE. Microcrystallme-granular, dark, feld- spathic base, with crystals of triclinic feldspar, abundant hexagonal plates of dark bronze-brown mica, and a few scattered quartz, grains. From the Black Spur, near Fernshaw. 157. MICA-PORPHYRITE. Same as No. 156. 158. MICA-PORPHYRITE. Same as No. 156, only feldspathic base of lighter colour. From the Black Spur, near Fernshaiv. 159. FELDSPAR-PORPHYRITE. Microcrystallme-granular, dark- green, probably chloride feldspar base, with crystals of triclinic feldspar, grains of quartz, and small, greenish-black, scaly patches of probably a " hydromica." Black Spur, near Fernshaw. 160. FELDSPAR-PORPHYRITE. Very fmely-crystalline-granular base, enclosing larger and smaller grains of quartz, crystals of triclinic feldspar, and small scales of black mica those of feldspar being predominant and most striking. From a dyke east of Emberton. Geological \ sheet 13 S.E. 161. FELDSPAR-PORPHYRITE. Same as No. 160, but- mica very scarce. Dyke east of Emberton. Geological -J- sheet 13 S.E.. b. LABRADORITE ROCKS. Rocks of this class are only known as yet from two localities- in Victoria, though judging from the occurrence of serpentine the general associate of some species (gabbro, &c.) in the Gippsland ranges, more localities will most likely be found there on further exploration of the country. 162. GABBRO, DIALLAGE ROCK. A coarsely-crystalline- granular mixture of light-green " labradorite," and of a dark- 25 green augitic mineral, which according to its lustre and cleavage is " diallage." Barrabool Hills, west of Geelong. Geological I sheet 24 S.E. 163. GABBRO, DIALLAGE ROCK. Same as No. 162. On one side affected by decomposition, the feldspathic component being in places wholly removed, leaving the diallage behind as an irregular hackly surface of interwoven crystals. yotc. This rock occurs as a pretty extensive mass, sur- rounded by mesozoic carbonaceous rocks, principally sandstone ; but is evidently older than the latter, on account of their being, interstratified with beds of coarse conglomerate, partly composed of rounded pebbles of it. On account of its fine colour and texture, it is well adapted for ornamental purposes, though its great hardness and toughness renders it rather expensive to work. On some specimens diallage has been observed of a darker colour than the rest, and with the angle of cleavage of hornblende, which would indicate an alliance to uralite. The- follovving are the results of analyses of the rock by Mr. J. Cosmo Newbery : Analysis of the Rock in mass. Soluble Portion. Insoluble Portion. Silica 50-84 46-34 53-94 Iron sesquioxide Iron protoxide . . Alumina Lime ... Magnesia Soda 0-52 6-90 12-92 14-35 10-97 traces 1-30 29-06 14-56 3-44 | 11-78 2-80 14-39 16-13 Potassa Loss by ignition Water 1-83 0-71 j- 4-51 1-75 ::: 99-13 100-95 99-04 40-06 per cent, is soluble in hydrochloric acid, and the analysis, of this portion proves it to be labradorite, whilst that of the insoluble one comes very near to the mean composition of diallage. 164. GABBRO, DIALLAGE ROCK. Very large-grained ; nearly wholly composed of interlacing crystals of greyish and greenish diallage, showing cleavage planes of fine pearly lustre, with but little, more or less decomposed, triclinic feldspar (labradorite), between. From the Serpentine of Mount Wellington, Gippsland. 2G J5. NEWER FELDSPAR ROCKS ; NEWER IGNEOUS OR VOLCANIC ROCKS. Of the four series of rocks belonging under this head viz. 7 the trachyte rocks, nepheline and leucite rocks, basalt rocks and younger anorthite rocks only the third the basalt rocks have as yet been observed in Victoria, though it is not impro- bable that some rocks from certain localities classed amongst them may belong to the nepheline series, as will be explained further on. As trachyte rocks exist in the neighbouring colony of New South Wales, and more extensively further north in Queensland, they may perhaps also occur in this colony in the ranges near the boundary of New South Wales ; but this could only be in small outcrops or dykes ; for that they should exist massively developed and be hitherto overlooked is extremely doubtful, as the country is too well explored. BASALT ROCKS. These rocks, which are essentially composed of auyite, labra- dorite, and titaniferous magnetic iron, are extensively developed in Victoria, being estimated to occupy from COOO to 7000 square miles of the surface. Their eruption took place during at least two distinct periods within tertiary times, and they are therefore divided into older and newer basalt rocks. The older basalts apparently the more widely distributed appeared at the end of the miocene epoch, whilst the eruption of the newer commenc- ing towards the close of the pliocene epoch seems to have been continued into the most recent post-pliocene times. In its phy- sical features the country occupied by these two basalts differs generally very much, and the geological observer has no difficulty in determining the nature of the rock. The older basalt country exhibits gently sloping rises with occasional higher smooth hills, the surface above the rock consisting of several feet in places up to 10 feet and more of a very fertile black, brown, or chocolate-coloured soil, which is doubtless the result of long- continued decomposition of the rock. It supports the most profuse and dense vegetation, hardly penetrable scrubs and forests, in which the trees of all kinds frequently reach gigantic dimensions 10 to 12 feet in diameter at the base, and up to 300 feet and above in height, being not uncommon amongst some of the eucalypti as, for instance, in the ranges east of Berwick, along portions of the Gippsland road, and in the Western Port District. As another effect of the long-continued action of decom- 27 posing agencies, the structure of the rock, though sometimes finely columnar or prismatic, is most frequently sphseroidal, poly- gonal, concretionary, and much jointed characteristic features, which destroy the use of the rock as a building stone com- pletely, but do not affect its applicability for road and railway- ballast metal, for which purposes it deserves indeed to be extensively used. Alternating with these hard layers are generally such of an unctuous, frequently amygdaloidal, soft clay, which shows all variations of colour from pure white to dark red, dependent -on the amount of hydrous oxide of iron admixed. In some places this clay is thickly traversed in all directions by ferruginous masses, which exhibit in section a concentric shell- like structure, due to the effects of advancing decomposition, and pointing to their representing but the nuclei of larger, irregularly- polygonal masses that originally composed the whole mass of the layer the clay now intervening being the result of the com- plete decomposition of successive concentric coats of these poly- gons. These various structures are well exemplified in the North Melbourne Railway and the Flagstaff Hill road-cuttings, but occur most extensively developed on the south coast of Phillip Island, on the shores of Western Port Bay, in the Pent- land Hills, near Bacchus Marsh, &c. Considering the mode of eruption of the older basalt, the absence of real craters, and the general scarcity, and in some districts total absence, of points of eruption, is very remarkable, arid seems to indicate that the rock mostly issued from large fissures or gigantic dykes ; whilst some of the smaller dykes, abundant in some dis- tricts (Cape Patterson, Western Port, &c.) may also have contri- buted their share to the outpour. On this account the specimens in the collection have been classed simply as basalt, and not as basalt-lava, the term lava being generally applied only to those rocks which have issued from, or whose origin can distinctly be traced to, craters or unmistakeable volcanic vents. The newer basalt has in this respect, in contrast to the older, to be called a lava ; for its extensive sheets and streams can in every case be traced either to distinct craters or to points of eruption, which latter seem in many instances to be filled-up craters, and show by scoria and cinders, abundantly strewn over their summits and slopes, plain evidence of their original office. As some of the principal craters may be mentioned Mount Franklin, Tower Hill, Mount Eels, Mount Noorat, Mount Napier, &c.; whilst of the great number of conical or mammaloid points of eruption, the three Anakies, Mounts Glasgow, Hepburn, Buninyong Kangaroo 28 Hill, Carisbrook Hill, fec., form well-known examples.* In contrast to that occupied by the older basalt, the newer basalt country presents thus generally wide, open, mostly rocky plains, studded in parts with conical hills and mountains; only in rare instances the plains are covered with forest trees, but not by far of the size and luxuriance as exhibited by the older basalt ; in fact, the boundaries of the newer basaltic sheets and streams- for instance, with the silurian are very frequently delineated by the commencement on the latter of forest, whilst clusters of trees within the lava-plains generally indicate silurian outcrops. To trace out with any claim to precision the particular portions which each of a number of volcanic hills contributed to an exten- sive lava-sheet surrounding them, is quite an impossibility, the generally even surface of the latter between the hills severally presenting no lines of demarcation or other guiding marks, and even the rock itself, of different parts of the plains or sheets, nearer the one or other of the hills, shows no serviceable distinc- tions either in structure or lithological character. These facts are substantiated by the relations of the numerous volcanic hills with intermediate lava-plains in all parts of the colony, and seem to< indicate that the action, if not the origin, of the different points of eruption, within or fringing a defined lava-sheet, was contem poraneous, at least within such limits as to allow of an inter- mingling and even-spreading of the fiery molten matter. An observation of Mr. Selwyn's in this respect bearing more espe- cially upon the nature of some of the craters and points of eruption is " That certain features exhibited by some viz., that the walls of the craters are formed of stratified layers of ash, dipping outwards at a low angle seem to indicate the probability of their having been sub-aerial volcanic vents, forming low islands in the tertiary seas, under the waters of which the lava streams- flowed and were consolidated." As the thickness of the basaltic sheets depends on the features of the original surface over which they spread, it varies accord- ingly, even within short distances, to a great extent. In the average it may be considered to range from a few feet up to 150 feet. There are exceptional places, however as, for instance, at Ballarat, where it exceeds 400 feet ; but this is due to the lava mass as a whole being composed of several sheets the so-called first, second, third, and even fourth rocks erupted and spread *See Mr. Selwyn's List of Craters and Volcanic Cones, "Exhibition Essay/" 1866, p. 34. 29 over each other at different periods, probably at considerable inter- vals of time, judging from clay and silt deposits occurring between the different sheets. With regard to a great number of the gold- fields of the colony the streams of the newer basalt have performed a most important office, and our miners, early recognising its nature, have reaped its benefits for years past, and will do so, no doubt, for years to come. The office alluded to is the preservation of large patches of older auriferous drift against the denuding agencies of post-tertiary times agencies that wrought our pre- sent, some even deeper, valleys than those of former days, and which in doing so have even largely affected the tough mass of the lava itself. To this bear striking testimony the numerous larger and smaller outliers of the rock in many valleys remnants of once continuous lava-sheets with their rugged outlines and steep rocky escarpments. But it is not to the miner alone that the basaltic table-lands prove sources of wealth ; the agriculturist also, though in a widely different sense, and not so restricted to special localities as the former, derives lasting benefit from them. The decomposition of the lava the very opposite that saved for the miner yields, like the older basalts, one of the most fertile, if not the finest, soil in the colony ; a quality no doubt due to its richness in special alkaline and other salts, necessary or favour- able for the growths of cereals and generally most products of husbandry. But it is apparently not so well adapted for forest growth as the soil of the older basalt, though in many cases of bare plains and patches of this basalt land, the thinness of the soil or decomposed surface-layer, evidenced by the rocky nature of the ground, is undoubtedly the cause of the absence of trees. The colour of this soil is, like that of the older basalt, black or dark-brown, sometimes also reddish-brown to brick-red, and its thickness very variable, ranging on the plains and the tops and slopes f the hills from a few inches to seldom over 3 feet, but often reaching 8 feet and over in the flats and gullies running between the hills or cutting through high plateaux. Irregularly distributed through the soil, both of this and the older basalt, occur nodules of hard, dense basalt, with a brownish surface-crust, concretions of carbonate of lime and magnesia, various in size and shape, and, as a special feature in many places, a kind of small reddish-brown grave], consisting of bean and kidney-shaped bodies of brown hematite. The small watercourses down the flanks of the hills show also generally titaniferous iron (menaccanite) in greater or less abundance. Beneath the fertile stratum of large portions of the plains there generally occurs a yellowish, tough, and soapy clay of variable thickness. It gradually merges down- 30 ward into the mass of the rock, and is therefore no doubt the result of the decomposition of the lava in situ, and not as might be supposed a deposit derived from other sources. The peculiar surface-feature of the plains, the network of small, shallow inden- 1 tations, forming waterpools in winter, is, as it seems^ mainly dependent on the existence of this clay. On viewing the steep escarpments of the large plains and outliers, we observe most frequently a vertical, more or less perfectly columnar or prismatic structure, the prisms being mostly 5-sided, sometimes 6-sided. This structure i.e., the vertical joints incident upon it proves often of some advantage to the miner in sinking shafts through the lava for the older gold drifts underneath. On the Kangaroo outliers, in the Loddon valley, for instance, many shafts may be seen, each of which has, as it were, been formed by the removal of one of the large lava prisms. Tabular structure is rather rare. A fine instance of it is met with in the neighbourhood of Kyneton, at the Little Coliban River. The rock shows there columnar and tabular structure combined i.e., on the large scale it is columnar ; but each column shows a finely tabular structure by being cleavable into thin slate-like plates, generally at right angles to its main axis ; the side planes indicate this structure by parallel striations and grooves, more especially where the rock is affected by decomposition. There are many localities where a nodular, sphaeroidal, or polygonal structure may be observed, and it is generally the case in these instances that the nodular masses consist of dense, dark rock, showing in section concentric bands of slightly varying texture and colour, whilst mostly a lighter, soft, or friable ferruginous mass fills the interstices between them. The origin of this structure is no doubt similar to that exhibited by the older basalt, described and explained in the foregoing. Another interesting feature not uncommon in the newer basalt of the Western District are large caves, about one of which, situated on the east bank of the Mount Emu Creek, Mr. Selwyn makes the following remarks : " It contains three large and lofty chambers, connected with each other by narrow passages. The first and largest chamber is 48 by 40 yards; the next (connected with the former by a short narrow passage), 44 by 27 yards ; and the furthest from the entrance (connected with the larger one by a narrow passage 13 yards long) is about 27 by 15 or 20 yards. Thousands of bats inhabit these caves, hanging in clusters from the roof like a swarm of bees, and on the floor are large conical mounds of a rich brown earthy matter, containing imbedded pieces of crystallized gypsum.*' The deposit itself consists entirely of the excrements of the animals. The average height of the chambers is from 15 to 20 feet. No explorations have yet been made in the caves."t Mr. Aplin, formerly of the Geological Survey, explored a large cave near Gisborne in 1856 (see plan of cave on Geological | sheet No. 7 X.W.), and found a large number of bones, amongst which Professor M'Coy determined, as the most interesting, remains of "Canis Dingo," or Wild Dog; " Diabolus (Sarcophilus) Ursinus," or Tasmanian Devil, of which genus no species is at present known living on the Continent of Australia ; " Dasyurus affinis" (M'Coy), new species ; " Phalangista," new species ; " Hypsiprimnus trisulcatus" (M'Coy), new species. As regards economic purposes, the newer basalt is of far greater importance than the older ; for besides yielding excellent road metal, the more compact bluish-grey kinds, commonly called " bluestone," are duly appreciated for architectural and engi- neering purposes, as fine durable building stone, being easily dressed, and procurable in blocks of all dimensions up to 50 and more cubic feet. Flags cut from some occurring in the neighbourhood of Melbourne, and used for portions of the footpaths in the city, have also, so far as experience goes, proved excellent for the purpose. There are certain basalt occurrences namely, some of the dykes the age of which is rather doubtful. Whilst those dykes, occurring, as for instance in the Western Port District, close to or within older basalt areas, are most likely of the age of the latter, a number of dykes exist in some of our western goldfields (Sandhurst and Castlernaine) at comparatively con- siderable distances from basalt centres, and therefore no clue whatever of their age is given. Considering, however, that only the newer basalt occurs around the respective districts, the specimens from some of these dykes in the collection have provisionally been classed as belonging to it. Touching the mode of occurrence of the Sandhurst and Castlemaine dykes, which are partly much decomposed, and called " lava-streaks" by the miners, it is of special interest on account of the close association of the dykes with auriferous quartz reefs namely, they form either the hanging or foot walls of the reefs, or, in rarer instances, break through the latter from side to side, * Small crystals of the rare mineral " struvite," are also abundantly dispersed through the mass. t The deposit has since been used by the farmers of the neighbourhood to great advantage as a valuable manure. 32 faulting them more or less features which indicate that the fissures of the reefs have mostly been the lines of least resistance for their eruption. Upon the auriferous character of the reefs, they could, on account of their far more recent age, not have had any genetic influence whatever, though some miners wrongly suppose so. In case of such a dyke traversing and faulting a reef, it may, however, happen that auriferous shoots or patches being thereby severed and the severed parts dislocated a level driven in one part does, on regaining the reef beyond the dyke, not strike the corresponding part, but poor or barren quartz instead. Speaking generally of the influence which these dykes and both the older and newer basalt exerted upon the rocks they came during their eruption in close contact with, it has, if any, as far as observation extends, been of but a slight and transient character. Granite underneath basalt-covers has apparently not been affected at all ; clay deposits elsewhere of grey or yellow colour, are, under these circumstances, changed to brick-red, and have lost their original toughness ; and with regard to silurian strata, the only, though doubtful, indication of a change is a peculiar perforated, as it were, vesicular texture of the slates and sandstones in the immediate neighbourhood of some points of eruption (Mount Consultation, Kangaroo Hill). Proceeding now to a special description of the older and newer basalts, relative to their lithological character, bearing in mind their essential mineral composition viz., " augite," " labradorite," and " titaniferous iron," we have in Victoria the three established sub-species viz., dolerite, anamesite, and basalt, besides an infinite number of varieties dependent on texture and other characters. (1.) Dolerite, Dolerite Lava. A crystalline-granular, dark and light-bluish or greenish-grey rock, in which crystals of its principal components, augite and labradorite, can be distinctly recognised by the naked eye. This species has not as yet been observed within the older basalt areas, and is also rare within those of the newer. Principal localities of occurrence are Malms- bury, Kyneton, Gisborne. (2.) Anamesite, Anamesite Lava. Of bluish or greenish, often brownish-grey or black colour, and distinctly recognisable, yet so finely crystalline-granular a texture, that the component minerals cannot be clearly distinguished without aid of the magnifying glass, and then only by their difference in colour. It is apparently the most prevailing. Its fracture is flat-conchoidal, with a glit- tering surface, and it is sometimes rendered porphyritic by crystals 33 of hornblende and oligoclase and grains of olivine. With reference to the older basalt of Phillip Island and the neighbour- ing shores of the main land, of which a number of specimens are represented and placed under this head in the collection, there is some probability that it belongs to the species nephelinite (nepheline-anamesite ; nepheline-basalt). To this supposition leads the recent discovery on the island by Mr. O. Rule, of a finely porphyritic variety of the rock, containing, dispersed through a rather dense, black base, numerous crystals (hexagonal prisms) of nepheline, some more or less decomposed, besides large plates of black or brown mica, patches of triclinic feldspar, apparently oligoclase, crystals of black hornblende, and large grains of tiiani- ferous iron. And what speaks further in favour of this view is the great abundance of zeolites, especially analcime and natrolite, in the rock of Phillip Island, and that the results of the analysis of specimens of non -porphyritic texture from that locality accord generally better with those given in books of nepheline basalts from foreign localities than with those made of basalts from other parts of the colony. (3.) Basalt, Basalt Lava. Dark-grey to mostly black, quite homogeneous-looking ; in fracture generally somewhat dull, though in some places (Little Coliban River, near Kyneton, Bacchus Marsh, &c.), quite of the aspect of Lydian stone. The texture of these three sub-species is in many places a thorough compact one, yet most frequently it is more or less porous and vesicular (honeycombed), the vesicles showing either, though rarely, a glassy surface inside, or being partly or wholly filled or coated with different minerals, whence results amygda- loidal texture. These accessory minerals will be described further on. In their mode of occurrence our three sub-species differ in some marked respects from those described from the basalt dis- tricts of Europe. The principal difference is, that they do not occur in distinct masses with defined outlines, as it is stated to be the case there, but form here rather irregular portions of undefi- nable size and shape, graduating one into the other, laterally as well as vertically, throughout the same sheet or stream of lava. They present in fact only, as it were, different forms and stages of mineral aggregation during the cooling of the molten matter. The same quarry yields thus frequently both anamesite and basalt, and at Malmsbury a quarry produces besides these also dolerite. As principal varieties, mostly of basalt proper, all well represented in the collection may be mentioned : (a.) Earthy Basalt, or, as it is called in France and Germany, Basalt Wacke A bluish, greyish, or brownish-black, mottled, 34 earthy-looking, and more or less vesicular mass, with frequently embedded nodules of a denser texture, found in some places on top of the plains, and also beneath sheets of hard basalt. It sometimes encloses scales of mica, crystals of hornblende and oligoclase, and is frequently amygdaloidal, the amygdules consist- ing of various zeolites, chalcedony, green earth, calcite, aragonite, &c. Much of the older basalt of Phillip Island and the neigh- bourhood of Melbourne belongs to this variety, which in most cases represents in fact nothing else but basalt in an advanced stage of decomposition. (b.) Basalt Scoria. Of dark-brown or black colour, highly vesicular or cellular the vesicles or cells irregular in size and shape, and showing glazed walls very similar to some of the slags of iron-furnaces. It occurs in masses of irregular shape, and of all sizes, principally on the tops and slopes of the craters and points of eruption. The same is the case with (c.) Basaltic Pumice. A scoria so spongy and light that it floats on water, and might, except for its black or brownish- black colour, and absence of fibrous texture, be mistaken for true trachyte-pumice. (d. ) Basaltic Ash. Earthy and compacted, ashy-grey or brown, sometimes mottled in these colours. Found near craters and points of eruption, frequently in stratified layers. The compacted kinds are in some localities (Warrnambool, Terang, &c.) advan- tageously used as building stone, being, when freshly broken, soft enough to be sawn into blocks of all sizes, but hardening con- siderably on exposure to the atmosphere. Both the older and newer basalt rocks are, as already mentioned, rich in accessory minerals, partly original, partly of secondary origin. As the most noteworthy original minerals may be men- tioned Olivine common in all our basalts, but more especially characteristic of the newer ; in fact itjs so frequent in places as quite to assume the place of an essential constituent of the rock. It is generally of an olive-green, sometimes emerald and bottle- green colour, has a glassy lustre, and appears in grains and larger and smaller nests or polygonal masses, of granular texture, up to several pounds in weight, irregularly distributed through the roc k (Anakies, near Geelong, in the rim of the crater of Mount Franklin, &c.) It seems to decompose more easily than the mass of the rock, leaving behind it a reddish-brown substance, prin- cipally consisting of hydrous ferric oxide. A transformation into a reddish-brown micaceous mineral (rubellane ?} has also been observed in the basalt of some of the Loddon outliers. Hornblende. Of a shiny pitch-black colour, often in perfect 35 prismatic crystals up to an inch in length, and J-inch thick ; is tolerably frequent in the older basalt of Phillip Island, and occurs in some of the newer basalt areas in very great abundance ; for instance, at the Anakies, where the centre one of these three points of eruption is literally strewn over with crystalline pieces and more or less perfect crystals of the mineral. Oligoclase. Pretty abundant in the older basalt of Phillip Island, and more especially in the rock of all crater hills and points of eruption of the newer basalt (Mount Franklin, Mount Elephant, Anakies, &c.), occurring in colourless, transparent, translucent, occasionally opaque white, crystalline grains, rarely in perfect crystals, and sometimes in irregularly-shaped bodies of above a cubic inch in size. A quantitative analysis by the late Mr. Charles Wood, analyst to the Geological Survey, of speci- mens from the Anakies, gave Silica, 64-22; alumina, 23'87 ; iron sesquioxide, 1'53 ; lime, trace ; magnesia, 0'38 ; soda, with some potash, 9 '87; = 99 '87 ; leaving no doubt about the identity of the mineral. Less frequent are : Mica Black or brown magnesia mica, in plates sometimes exceeding a cubic inch in size, occurs occa- sionally in the older basalt of Phillip Island, and in the newer basalt of the Loddon plain, near the Muckleford Creek, also in a dyke adjoining the Eureka Reef, near Castlemaine, and in some of the basalt dykes of Sandhurst. Nepheline. Only found in the older basalt of Phillip Island (see previous remarks under Anamesite.) Quartz. Occurs in the newer basalt of Baringhup, near Maldon, pretty frequently in grains, and irregular patches of bluish-white colour, and in such association with the rock as to leave no doubt of its original formation in it. In some localities, however as, for instance, at the Green Hills, near Kyneton, Mount Franklin, &c. are found pebbles and fragments, much fractured, and of opaque white colour, in the rock, which were no doubt mechanically enclosed during the eruption of the lava. Obsidian. Occurs at Geelong, Ballarat, and in the crater hills and plains of the Western District ; in the latter localities, generally in small, button-like pieces, and sometimes larger balls, hollow and glazed in the centre. A black, pitchstone-like mineral, probably Tachylite, has been found at Phillip Island. Zircon and Sapphire These two precious stones, although not as yet observed actually implanted in the rock, are most likely analogous to European occurrences not rare in the basalt of many localities, judging from their frequency in the alluvial or recent gold-drifts of creeks and gullies running between basalt outliers, or cutting through basalt plains, whilst in similar drifts D2 36 outside the basalt areas, or in the older gold-drifts underneath the basalt, they are either rare or quite absent. (Blue Mountain gold- field, Loddon Valley, Daylesford, &c.) Black Corundum In irregular grains, rare, at Phillip Island. Amongst the secondary minerals, deserve mention a number of species of zeolites, viz.: Analcime and Natrolite, in fine crys- tallisations, very abundant. Gmelinite and Heulandite; rare in the amygdaloidal, wackenitic, older basalt of Phillip Island. Chabasitej in fine druses; frequent in decomposed older basalt of the Pentland Hills, near Bacchus Marsh, and in newer basalt, near Malmsbury and dunes'. Herschelite, in beautiful crystal- lisations, some quite new to science ; plentiful in the newer basalt of Richmond, and rare in that of Clunes. Mesolite ; frequent at Glunes. Phillipsite ; frequent at Richmond, rare at Malmsbury. Of other minerals the most abundantly distributed throughout the basaltic areas is Aragonite ; occurring in fine acicular crys- tallisations, crystalline coatings, and in nodules with concentric radiating structure. Next in frequency of occurrence, mainly in decomposed basalt, follow : Brown Iron-ore, Chalcedony (Phillip Island); Common Opal, Hyalite (in transparent reniform crusts at Kyneton) ; Calcite, Sphcerosiderite, Green Earth, Soapstone, Halloysite, &c. All the species mentioned are represented in the collection of Victorian Minerals. OLDER BASALT ROCKS. 165. ANAMESITE (NEPHELINE ANAMESITE ?). Finely crys- talline-granular, solid, rendered slightly porphyritic by grains of olivine ; shows an imperfectly slaty cleavage. One mile east of East Creek, coast of Western Port Bay. 166. ANAMESITE (NEPHELINE ANAMESITE ?). Finely crys- talline-granular and solid. Phillip Island. 167. ANAMESITE. Very finely crystalline-granular, solid, and micro-porphyritic. Saltwater River, near Melbourne. 168. A.NAMESITE (NEPHELINE ANAMESITE?). Finely crys- talline-granular, slightly amygdaloidal. Phillip Island. 169. ANAMESITE (NEPHELINE ANAMESITE?). Finely crys- talline-granular, rendered porphyritic by small crystals of nepheline, a few scales of brown mica, and large crystalline patches of oligoclase and black hornblende. The weathered face appears slightly vesicular, apparently in consequence of the removal, through decomposition, of the hexagonal prisms of nepheline. Phillip Island. 37 170. ANAMESITE (NEPHELINE ANAMESITE 1). Finely crystal- line-granular, and rendered porphyritic by crystals of nepheline, scales of brown mica, and patches of a mineral resembling tachylite. Phillip Island. 171. ANAMESITE (NEPHELINE ANAMESITE 1). Very finely crystalline-granular, wackenitic and amygdaloidal, with grains of oliviue in course of decomposition, the amygdules consisting partly of a steatitic, partly of zeolitic substance. Phillip Island. 172. ANAMESITE (NEPHELINE ANAMESITE?). Finely crystal- line-granular, but considerably affected by decomposition ; wackenitic and amygdaloidal ; contains druse-cavities, with fine crystals of analcime. Phillip Island. 173. BASALT (NEPHELINE BASALT ?). Quite dense and com- pact, and rendered porphyritic by small crystals of nepheline and large crystalline patches of oligoclase. Phillip Island. 174. BASALT (NEPHELINE BASALT ?). Dense, with small hackly fracture, and rendered slightly porphyritic by grains of olivine and crystals of oligoclase. Cape Schanck. 175. BASALT. Strongly decomposed, and partly converted into impure brown iron ore. Saltwater River, near Melbourne. 176. BASALT. Quite decomposed, and changed into impure mammillary brown iron ore. Saltwater River, near Melbourne. 177. BASALT. Thoroughly decomposed, and altered partly to impure brown iron ore, partly to a baked-looking red and yellow indurated clay. North Melbourne. 178. BASALT (NEPHELINE BASALT 1). Strongly affected by decomposition j of wackenitic character. Coast, of Western Port Bay. 179. BASALT. Strongly decomposed and amygdaloidal. The white mineral forming the amygdules is, probably, halloysite. Stony Hut, Mount Blackwood. 180. BASALT. Thoroughly decomposed, and converted into a brown and white mottled, earthy clay, very light, and slightly soapy to the touch. Raleigh's Punt, Saltwater River. Geological i sheet 1 N. W. 181. BASALT (NEPHELINE BASALT ?). Quite decomposed, and changed into a minutely red and white-mottled, indurated clay. South-west of East Creek, Western Port Bay. 182. BASALT (NEPHELINE BASALT?). Same as .foregoing. South-west of East Creek, Western Port Bay. 183. BASALT (NEPHELINE BASALT ?). Decomposed to red, baked-looking clay, which presents in places quite a porphyritic appearance, imparted by more or less decomposed, glistening grains of, probably, olivine; shows also small patches of a 38 yellowish- white mineral resembling halloysite. Coast of Western Port Bay. 184. BASALT, (NEPHELINE BASALT?). Decomposed to red, baked-looking clay. A portion, of a lighter shade of red, is slightly vesicular, and rendered amygdaloidal by whitish, irregu- larly-shaped granules of a mineral resembling halloysite. Coast of Western Port Bay. 185. BASALT. Decomposed to grey and white-mottled soapy clay, traversed by veins of white, soapy clay. West Melbourne. Analyses of the Older Basalts from Phillip Island by Mr. Cosmo Newbery : i. II. in. i 1 * T, y a. t>. a. b. -Silica Alumina Iron sesquioxide Iron protoxide 25-45 28-67 12-50 37-22 21-16 9-11 33-24 17-18 29-46 34-16 23-22 12-09 49-46 8-21 1632 35-44 8-13 31-43 54-73 19-12 6-03 Lime Magnesia Potash Soda Mang. protoxide Titanic acid . . . Water 6-07 4-37 0-91 5-32 15-48 7-02 6-21 J8-46 8 : 80 3-12 2-08 0-06 1-62 10 : 32 5-21 12-34 3-10 5-28 0-46 0-04 2-16 7-26 18-76 trace 5-24 17-33 traces 1-40 f-03 10-14 5-05 2-11 trace 98-77 97-98 97-08 98-06 100-01 100-00 97-18 I. Decomposed ; colour grey. Specimen dried at 212 F. Loss in weight at a red heat, 15-48 per cent.; portion soluble in acetic acid, 7 '3 5 per cent.; portion soluble in hydrochloric acid, 59-45 per cent.; insoluble residue (clay), 39-72 per cent. The analysis is of the soluble portion. II. Decomposed; colour grey. Specimen dried at 212 F. Loss in weight at red heat, 8*809 per cent.; soluble in hydro- chloric acid, 59131 per cent. The analysis is of the soluble portion. III. Decomposed ; colour red. Specimen dried at 212 F. Loss by ignition at a red heat, 10'32 per cent. Soluble in hydro- chloric acid, '58-63 per cent. The analysis is of the soluble portion. IV. Dense black; containing crystalline grains of olivine. Soluble in hydrochloric acid, 49-18 per cent.; insoluble residue, 50-82 per cent, (a.) Results of analysis of soluble portion. (6.) Hesults of analysis of insoluble portion. 39 * V. Dense black, containing a few crystalline grains of olivine, which were separated from the portion analysed. Soluble in hydrochloric acid, 46'22 per cent.; insoluble residue, 5378 per cent, (a.) Are the results of analysis of the soluble ; (6.) those of the insoluble portion. NEWER BASALT ROCKS. 186. DOLERITE LAVA. Coarsely-crystalline-granular mixture of labradorite and augite, with much titaniferous iron and small scales of ironglance ; highly vesicular. Quarries near Malms- bury. 187. ANAMESITE LAVA. Finely crystalline-granular, and rather porous; full of fine scales of ironglance. Section 40 of Kedesdale, Dalhousie. 188. ANAMESITE LAVA. Finely crystalline-granular; full of small grains of olivine ; very compact. Malmsbury. 189. ANAMESITE LAVA. Finely crystalline-granular, and rather porous ; full of small grains of olivine ; small crystalline grains of magnetic pyrites more or less converted into brown iron ore abound throughout the mass, causing it to affect the magnetic needle with a high degree of polarity. Magnet Hill, Bayntoris Station. Geological J slieet 5 1 S. W. 190. ANAMESITE LAVA. Very finely crystalline-granular ; contains large cavities coated with aragonite. Table Hill, near Guild-ford. 191. ANAMESITE LAVA. Finely crystalline-granular; rather porous, and rich in fine scales of ironglance. Bank of Yarra .River, near Footscray. 192. ANAMESITE LAVA. Finely crystalline-granular, and com- pact, with scattered grains of olivine. Yapeen Hill, Campbell's Creek. Geological -J sheet 15 N.E. 193. ANAMESITE LAVA. Finely crystalline-granular ; shows irregular cavities coated with herschelite. Basalt Quarries, Richmond. 194. ANAMESITE. Very finely crystalline-granular, and com- pact, with thick slaty cleaveage. From a so-called lava dyke on the Garden Gully line of reef, Bendigo. 195. ANAMESITE. Very finely crystalline-granular, and slightly vesicular ; the face coated with small crystals of iron pyrites. From a so-called lava dyke, Christmas Reef, at 215 feet level, Bendigo. 40 196. ANAMESITE LAVA. Very finely crystalline-granular ; rather porous ; contains abundant fine scales of ironglance, and is traversed by small, more or less parallel, broken veins (originally connected, compressed vesicles) of carbonate of lime. South-west corner of township of Mia-mia, Spring Plains. 197. ANAMESITE LAVA. Very finely crystalline-granular ; full of compressed vesicles, some of which being filled with aragonite, resemble irregular broken veins. From near Keilor. 198. ANAMESITE LAVA. Very finely crystalline-granular, rather dull-looking and slightly porous ; contains larger irregular cavities coated with carbonate of lime. Table Hill, near Guild- ford. Geological \ sheet 15 N.E. 199. ANAMESITE LAVA. Finely crystalline-granular; rather porous; shows attached a curiously-shaped mass resembling a coprolite, which, being harder and denser than the rest of the rock, has probably weathered-out through decomposition of the latter. Footscray, near Melbourne. 200. ANAMESITE. Very finely crystalline-granular, compact, microporphyritic. From a dyke north-west of Campbell's Creek, about 12 chains north of point ivJiere the road from Eagle Tavern to Muckleford passes a small basaltic outlier. Geological 4- sheet 15 N.E. 201. ANAMESITE PORPHYRY. Very finely-granular, apparently dense and compact, black base, impregnated with crystals of hornblende and grains of olivine. From a dyke adjoining the Eureka Reef, Castlemaine. Note. In some parts of this dyke there occur also large plates (up to 1 inch in diameter) of brownish-black mica. The dyke has apparently exercised neither a disturbing nor a metamorphosing influence upon the reef and adjoining silurian strata. 202. BASALT LAVA. Apparently quite dense and compact \ affects strongly the magnetic needle. (See specimen No. 189). Magnet Hill, Bayntoris Station. Geological J sheet 51 S. W. 203. BASALT LAVA. Dense and compact, in places slightly vesicular ; mottled brownish-red and black. Mount Consultation. Geological % sheet 15 N.E. 204. BASALT LAVA. Quite dense and homogeneous, resem- bling Lydiari stone; rendered porphyritic by small grains of olivine and feldspar ; slightly vesicular, the vesicles strongly compressed in one and the same direction. Little Coliban River, near Kyneton. Geological \ sheet 9 S.E. Note. A very similar variety of basalt occurs also in the neighbourhood of Bacchus Marsh. This rock was used by the natives for fashioning spear-heads, and in sharp-edged fragments for cutting purposes, 41 skinning native animals, 1 r- 1 O rH C O O IDlO JOf^-l lO O4 CO b- O CO < O O O O rH -JH O -* CO CO O : IG> O g rH CO "tl ' rH 43 7 j __i 1 ^ I - c; r> O > <>) . O O CO x> co us : o S <^i 3 M5 O rH O CO CO i-H , . . . ** oj : -^ cb o t- co o J : : t- rH (> .O JOOCO IrH CO * r-l CO O . . lOr-f (M CO ^ O i-H O r- 1 : o i-i o rH 10 : : : : -*coco ^co -*rHTtH .^CO ibooAi : *b fr* CO CO rH osi-tco eoi-i I-H i-igco CO rH O .Cq^< . (M Q? ^ 2 opioo :^2 : : : :^ -*OOOO *t>.^ ' * fH ' * rH CO CO i-t + -t^ . 1 4 ! 1 0) t>> fST 2 TS a I I II '. R S3 4j " f t i -a iKjf! ji i !! 'm jj . "~! O St**-i2 si'-gst^-s It^^a IflffilllMI 46 IL ROCKS OF SPECIAL CHARACTER AND COMPO- SITION, MOST WITHOUT FELDSPAR. Rocks of this class are, as far as observation extends, very rare in Victoria, only two species having as yet been discovered, viz., Epidosite and Serpentine. 241. EPIDOSITE, EPIDOTE ROCK. A coarsely-granular mix- ture of yellowish-green epidote and quartz, with scattered crystals of black hornblende ; associated with diorite. This rock occurs in the lower silurian ranges, about 2-J miles south- east of Tarilta (a little township on the Kangaroo Creek, seven miles south of Castlemaine), forming a zone of uncertain width, between an intrusive patch of diorite and silurian slates and sandstones. (See note 20, geological \ sheet 15 N.E.) A care- fully selected sample of the pure green rock showed a specific gravity of 3 '25, and two quantitative analyses by Mr. J. Cosmo Newbery one of this, the other of a more quartzose portion gave respectively : No 1. No. 2. Dense Green Rock More Quartzose Sample. Silica . 51-80 59-62 Alumina . .. 20-80 > 17-86 SesquioxicU } of ir )n 15-20 .. 5-60 Lime 12-20 14-65 Magnesia , .. traces traces Potassa . .. traces traces Soda % traces traces Water . 2-48 100-00 100-21 The composition of No. 2 agrees tolerably well with that of epidosite, from Canada, analysed by Dr. Sterry Hunt. A calculation to determine the amounts of quartz and pure epidote in rock sample No. 1 gave 16 per cent, of the former, and 84 per cent, of the latter. Deducting the former from the silica of the analysis, and calculating the remainder again to percentages, leaves a composition for the epidote which agrees tolerably well with that of the variety pistacite. (See " Contributions to the Mineralogy of Victoria" page 18.) 242. SERPENTINE. Resembles precious serpentine, but is rather hard. Might be suitable for ornamental purposes. Beechworth District. 243. SERPENTINE. Of uniform dark-green colour, and rather hackly fracture. Probably transmuted diallage rock, with which it occurs associated. Mount Wellington, Gippsland. 47 II. CRYSTALLINE- SCHISTOSE SILICATE ROCKS; METAMORPHIC ROCKS. Geological exploration has not disclosed in Victoria the exist" ence of any such extensive tracts of these rocks as occur, for instance, in Europe, and more especially in North America. Only two localities are known where, comparatively speaking, large areas are occupied by them. One of these, which surrounds a central mass of granite, is west of the Grampians, near the western boundary of the colony ; the other in the eastern and north-eastern part of Gippsland, and within it lies the Omeo gold-field. The rocks exposed at both localities are generally very similar in character, representing gneiss and foliated mica, chlorite, talc, serpentine schists, and argillaceous mica- schists, with intercalated layers and irregular masses of hard brown quartzite, the whole abundantly traversed by larger and smaller veins of white quartz. Of the age and rela- tions of these rocks nothing definite is known at present ; the probabilities are that the rocks of the first locality are either a formation older than lower silurian, or represent highly meta- morphosed lower beds of the Grampian upper palaeozoic series, whilst the Gippsland rocks may either be older than lower silurian, or form metamorphosed upper silurian beds. Smaller developments of these crystalline-schistose rocks of lower and upper silurian age are, however, very abundant ; in fact, they occur zone or mantle-like round all the granite areas ; and certain species, though of less extent, round all the massive outcrops of greenstone or other plutonic rocks. The width of these metamorphic envelopes is rather limited, one or two miles being perhaps the average, and it is generally greater in the direction of the strike than across it. Definite outside boun- daries cannot, however, be fixed, for the reason that the crystalline-schistose character, whilst most complete and intense along the lines of junction with and in the immediate neighbour- hood of the plutonic rock, becomes gradually weaker and weaker, or less pronounced, the further away from it, until it insensibly disappears. From the fact that the prevailing strike and dip of the strata is in most cases not in any way influenced by the granite, the one or other being frequently right on to or against it, Mr. Selwyn's proposition "that many of the granite masses- 48 are in no sense intrusive or irruptive, but represent in reality the completely transmuted ends of the Silurian rocks," receives strong confirmation. For the change of the latter into granite, the chemical composition of the two rocks presents no valid hindrance, as has been clearly shown by the results of chemical analysis ; but even without these data, a number of occurrences (for instance, near Mount Tarrangower, Mount Kingower, Mount Korong, &c.) demonstrate the change ocularly. Prominent amongst these are the so-called inliers of silurian rock small patches, some half an acre in extent right within the granite masses ; for, whilst at the surface still plainly exhibiting strati- graphical features, i.e., strike and dip accompanied by gene- rally a gneissose or hornfels-like character, these distinctions gradually disappear, not only round the margins of the inliers, but more conspicuously in depth, as clearly seen in favourable sections, and the transformation of the schist into granite is unmistakeable. A singular feature in connection with this is, that both strike and dip of these inliers are generally the same as, or but little discordant with those of the main formation nearest outside the granite masses. As regards the species of crystalline schists occurring within the metamorphic girdles, nearly all the principal ones, with numerous varieties, have been observed either in the one or other part of the colony, and are represented in the collection, those of lower silurian age being the most abundant. The rarest is granulite (leptinite), whilst varieties of argillaceous mica-schist, especially the peculiar knotted or nodular schists are the most frequent. True gneiss is also rather scarce ; but a peculiar rock, to which the name cornubianite has been given (from its great abundance in Cornwall), and which in texture and general character is more nearly related to gneiss than to any other species, and therefore considered a variety of it, is very common. Round diorite greenstone- masses, which nearly exclusively occur within districts occupied by upper silurian strata, the latter have mostly been converted into cherty or jaspery quartzites, though generally but for some short distance from the boundary of the greenstone. In an economic point of view, these rocks have proved of importance for the production of excellent flagstones of the knotted argillaceous mica-schist character, which have now entirely superseded the once largely-imported Scotch flagstones. They are found in several localities, the principal one being in Specimen Gully, Barker's Creek, near Castlemaine, where exten- sive quarries have been opened, producing flags of first-rate 49 quality, and of all sizes up to 80 feet square and larger. The cleavage of these flagstones is coincident with their dip, i.e.. y nearly vertical, a feature greatly favouring the quarrying opera- tions. Impressions of graptolites, though rather weak and im- perfect, have occasionally been observed in these flag-beds. Auriferous quartz reefs, some very rich, are the only mineral deposits of economic value as yet known and worked in these rocks ; for instance, at Maldon, Stawell, Kingower, hill twelve miles north-east of Sandhurst. 55 310. METAMORPHIC QUARTZ ROCK (METAMORPHOSED SHALE). Of similar character as No. 309. From a hill twelve miles north-east of Sandhurst. 311. METAMORPHIC QUARTZ ROCK (METAMORPHOSED SHALE). Of similar character to Nos. 309 and 310, but slightly ferru- ginous, and banded in very faint shades of greenish and yellowish- grey colour. From a hill twelve miles north-east of Sandhurst. 312. METAMORPHIC QUARTZ ROCK (METAMORPHOSED SHALE). Of similar character to No. 311, but banded structure (yellow- ish-grey and black) very distinct, and some of the bands have a more coarsely-granular texture. From a hill tivelve miles north- east of Sandhurst. 313. METAMORPHIC QUARTZ ROCK. Distinctly fine-granular, and densely impregnated with grains and crystals of decomposed feldspar, which impart to the rock a porphyritic appearance ; in parts slightly porous. From between Violet Town and Seymour. 314. METAMORPHIC QUARTZ ROCK. Fine-granular, compact and tough. Costerfield. 315. METAMORPHIC SANDSTONE. Fine-grained and highly micaceous ; full of irregular, small, ferruginous quartz veins, which, being more or less decomposed, present partly open fis- sures ; slightly laminated. From between Violet Town and Sey- mour. III. AQUEOUS ROCKS ; SEDIMENTARY ROCKS ; STRATIFIED ROCKS. The rocks comprised under this head are always regularly strati- fied i.e., arranged in distinct and defined "layers," "beds," or " strata," of greater or less extent. They form the greater part of the crust of the earth, as far as the same is open to our inspection, and owe their origin and structure partly and these form the more extensive section to the mechanical action of water on material derived from the disintegration of pre-existing rocks, hence the term " derivative rocks," sometimes applied to them ; partly to chemical action, either ordinary or exerted through or- ganic agencies plants or animals. Regarding these different modes of origin we may therefore divide the aqueous rocks into two main divisions, viz. 1. Mechanically -formed rocks; and 2. 56 Ohemically-forined rocks ; which latter include as a subdivision the organically-formed, or simply organic rocks. The mechanic- ally-formed rocks may, according to their texture and compo- sition, be subdivided into conglomerates, breccias, sandstones, quartz rocks, shales, mudstones, clay-slates, clays, and earths ; whilst the chemically-formed rocks are represented by the various limestones, gypsum, coal, &c. The quartz rocks, it might per- haps be considered, ought more properly to have been included amongst the chemically-formed rocks, as their origin may partly have been due to chemical action ; however, as some appear certainly of mechanical-sedimentary origin, and, on account of the uncertainty obtaining on this point as regards others, it seemed more advisable to class them as " mechanically-formed." Nearly all these kinds of rocks occur in each of the great geo- logical formations, viz. : The Palaeozoic, or Primary ; the Meso- zoic, or Secondary ; and the Cainozoic, or Tertiary, up to the Recent ; and as these formations are all represented in this colony either by one or more of their main subdivisions, the ar- rangement of the specimens in the collection strictly in accordance with the above scheme, without any reference to their geological age, would have been connected with the great disadvantage of placing specimens from the oldest to the newest formations indiscriminately side by side. Some of the sandstones, the quartzites, limestones, &c., of the upper divisions of the tertiary formation differ, for instance, neither in solidity, hardness, or general lithological character from such derived from the secon- dary or primary formations ; in fact, several are quite identical in texture, composition, and appearance. In order to avoid this intermixture, and to render the collection more instructive, the above classification has therefore been subordinated to strati- graphical arrangement i.e., the specimens from each of the great geological formations, and, if well established, of their main sub- divisions, have been grouped together and classified according to the introductory lithological scheme. PPvIMARY OR PALEOZOIC ROCKS. LOWER PALEOZOIC SILURIAN. As far as our geological knowledge of this colony extends, the oldest rocks as yet recognised are of silurian age. They occupy amongst the aqueous rocks by far the greater area, and 57 occur from sea-level up to the tops of mountains about 5000 feet in height. On account of the great amount of folding and other disturbances the strata have been subjected to, as evidenced by the alternation of anticlinal and synclinal axes, often at very short distances apart, the whole thickness of the formation cannot be accurately determined ; Mr. Selwyn estimated it approximately to at least 35,000 feet. From the numerous fossils discovered in all parts of the series, Professor M'Coy was enabled to subdi- vide the formation into the lower and the upper silurian, corre- sponding .\s homotaxeous deposits respectively with those of the same designation in Great Britain and other countries. The lower silurian series are characterised by numerous typical genera and species of graptolites, less abundantly by a small crus- tacean heminocaris, and rarely by siphonotreta and lingula. They are principally developed as the " true bottom-rock" in our western goldfields, and consist as exemplified in the collection of a (lithologically) little-varying series of hard, quartzose, gritty, and soft micaceous sandstones, slates, and mudstones conglomerates, breccias, and quartz rocks being rather scarce, and limestones having not as yet been met with. Owing to the rarity or absence of such distinctive beds as these, and to the general simi- larity of character and texture prevailing amongst the sandstones, mudstones, and slates, as well as to the want of variety amongst the fossil forms, which are almost solely confined to the slates for instance, the same genera and species of graptolites being met with throughout the series no means exist at present for iden- tifying individual beds, or for separating this formation into groups or subdivisions. The general strike of the strata is nearly meridional, and their dip nearly invariably at high angles, vary- ing from 60 to vertical. Amongst the slates and argillaceous beds, true slaty cleavage is of common occurrence, but it frequently very nearly coincides with the planes of stratification or bedding a feature which may account for the fact that slates which split thin enough, and have all the appearance of good roofing slates, are yet of not sufficient toughness to stand holing and trimming ; the generality break during the operation. The colour of the sandstones, slates, and mudstones varies very much, sometimes within very short distances in the same beds. The sandstones show at the surface mostly different shades of grey, brown, and more rarely red ; the slates and mudstones of white, pale to dark grey, brown, pink, purple, blue, and more rarely black and red ; varieties variegated, mottled, or finely banded in different colours are not uncommon. Admixed oxide of iron is no doubt the chief colouring matter of the vivid colours ; for in depth 58 beneath the water-level, where the iron exists impregnated in the state of finely-divided bi-sulphide, or iron pyrites, the prevailing colours are invariably dark-grey, blue, black, and more rarely green. Similar variety and variation as in colour is also observable in the texture and hardness of these rocks, more especially the sandstones. These show all gradations from fine to coarse-grained and gritty, from soft and friable to very tough and hard. The prevalence amongst them of soft and argillaceous varieties is a noticeable, though unfavourable feature, as regards the probability of their yielding building stone of a permanently durable cha- racter, irrespective of another unfavourable quality, namely, of their being generally impregnated to a greater or less degree with soluble salts, which render them liable, at the faces exposed to the weather, to rapid exfoliation and steadily progressing decay ; most are also too much fissured by joints and cracks and traversed by ferruginous and quartzose veins. The upper silurian series rest unconformably on the lower, and whilst also containing different typical forms of graptolites, are in parts especially rich in genera and species of brachiopoda, lamellibranchiata, crinoidea, trilobites, starfish, &c., which ally the greater extent of the strata (according to Professor M'Coy) to the May Hill sandstone group, or the base of the upper silurian some to the Wenlock-shale group. As shown on Mr. Selwyn's sketch-map of Victoria, they extend in great synclinal and anti- clinal undulations, from a few miles west of Melbourne, eastward to the meridian of Wilson's Promontory ; exhibiting, wherever found in contact with the lower silurian, a considerable unconfor- mity to the latter. There exist generally, also, striking differences in general lithological character and mode of stratification between the two series, inasmuch as rubbly or indurated and highly frac- tured argillaceous shales rare or quite absent in the lower are very abundant in the upper, whilst the beds of the latter strike but rarely meridional, and dip generally at low angles dips from 20 to 40 being frequently observable. As regards building stones, roofing slates, flagstones, &c., their scarcity in this series is still more conspicuous than in the lower silurian. Of limestones only one small band, a grey marble, has as yet been disco vered., on the Upper Yarra, in the parish of Yering.* * Since the above was written, a tine deposit of crystalline limestone (marble), over 100 feet thick, has been made known on the western shore of Waratah Bay, about three miles north of Cape Liptrap. This limestone is probably of upper silurian age, and a specimen will be found in the collection, as No. 446a, at the end of the upper silurian series. 59 As was noticed in the previously-described section of the crys- talline-schistose silicate rocks, both the lower and upper Silurian strata are round granite or other plutonic rock-centres, invariably more or less metamorphosed in zones or mantles of variable generally limited width; and as full particulars have there been given concerning the kinds of change they underwent and of their geological relations to those rocks, these points need not here be adverted to. With regard to its mineral capabilities, the silurian, as a whole, is the most important rock formation to the gold miner, on account of its containing the matrix of the gold in the countless number of veins, lodes, or reefs of quartz that tra- verse it the number of those actually proved gold-bearing amounting already, according to Mr. R Brough Smyth's Mining Statistics of 30th of June, 1874, to 3367, and being still steadily on the increase through the untiring prospecting energy of our miners. These reefs vary from less than 1 inch to above 100 feet in thickness, whilst their longitudinal extent ranges from less than 100 feet to several miles. Their mean strike is, in the lower silurian series, generally conformable to that of the strata ; reefs that cross the latter being very scarce (Taradale and Stawell are the chief localities where cross reefs occur one at the latter place being celebrated for its richness in gold). In the upper silurian there are more exceptions to this rule ; and it must also be remarked that this series is not by far as rich in genuine quartz- reefs, and those found though in the average, perhaps, richer in gold per ton of stone are not as thick and persistent as those of the lower series. The greater amount of quartz -gold produced by upper silurian districts comes from irregular blocks and veins that traverse, or are closely associated with, dykes of diorite-greenstone, as mentioned in the description of this rock. Regarding the dip or underlay of the reefs, it varies at all angles between nearly horizontal and vertical, and coincides not only in most cases in direction with the dip of the strata, i.e., either east or westward, but its angle is often so nearly identical with that of the latter as to impart to the reefs the appearance of interstratified deposits. If it was not for the frequency of lateral branches " leaders"- joining the main bodies at all angles, both at their hanging and foot walls, they would in reality have to be considered as " layers" or interbedded deposits ; but, as it is, they represent in these cases so-called " layer or bedded lodes." Another feature of importance is, that many reefs show, from the surface downwards, an endlong dip, or a dip in strike either north or southward, sometimes in both directions, whence follows 60 an expansion in depth. Prominent amongst the former are the so-called " block reefs," i.e., reefs which in their longitudinal extent show frequent contractions, consisting, as it were, of a series of in horizontal section lenticular-shaped blocks, fre- quently of considerable thickness in the centre, which are con- nected at longer or shorter distances, sometimes by thin veins of quartz, sometimes by ferruginous clay-casings only, and each block dipping from its outcrop at a certain angle rarely at right angles to the line of strike either north or southward, i.e., the blocks of one and the same reef, and generally of all the reefs in a dis- trict, show invariably the same direction of dip northward being the most frequent. The expression, often used by our miners, " that it requires a shaft of a certain depth, either north or south of an outcrop, to strike the "cap" of a reef, refers to this feature, and will thus be easily understood. A peculiar and interesting occurrence are the so-called " saddle reefs," as especially well exemplified in the Hustler's Great Extended Company's mine, Sandhurst. As the term indicates, a reef of this class presents, in east and west section, the shape of a saddle, i.e., a generally very thick central part with a certain flat dip in strike, either north or south bends whilst decreasing in thickness sharply downward on either side ; and of these lateral parts, the so-called eastern and western legs, one dips generally with the strata, whilst the other opposite one crosses them. In the above mine several such saddles have been found to succeed each other at various depths. The mode of occurrence of the gold in reefs can be brought under the following main heads : 1. The metal is equally distributed throughout the whole thick- ness and extent of the reef. This seems to be the rarest occur- rence. Generally richer and poorer places alternate, especially where the thickness of the reef changes, the contracted portions being mostly richer than the wider ones ; but the contrary having also been found to be the case, in a marked manner in some reefs, no rule can be established in this respect. 2. It exists in irregular larger and smaller patches, both in strike and dip, throughout the reef. More frequent than the former. 3. It occurs most frequently in so-called "shoots," i.e., in stripe or band-like areas or portions of the reef of various widths, which dip at various angles, either north or southward in strike ; rarely at right angles to the latter. Both the width and angle of dip of the shoots vary in each individual case generally but little, allowing thus tolerably accurate calculations to be made as to the depth at which a shaft, for instance, situated some dis- 61 tance from its outcrop, ought to strike such a shoot in the direc- tion of its dip. 4. A not uncommon case, especially in strong reefs, is that the auriferous portions, either irregular patches or shoots, occupy only a certain width along the hanging or foot walls, more rarely along both walls, whilst the remainder of the reef is barren. Some exceptional cases have also been observed, however, of the gold being confined to a certain width in the centre of strong reefs, the quartz along both walls proving worthless. Most of these occurrences form structural features of the respective reefs, inasmuch as the gold-bearing portions represent separate bands, divided by thin black casings from the rest ; they appear, in fact, different in date of formation from the latter, either older or newer, thus indicating a re-opening and successive filling of the reef fissures. Touching the depth to which the gold extends in our reefs, the hypothesis advanced by high authority in the early days of the goldfields, namely, " that the metal would be found to quickly decrease in quantity, and entirely to disappear at a limited depth," has, fortunately for the prosperity of our quartz-mining industry, proved, in the main, incorrect. For depths of between 500 and near 1000 feet, at which payable stone is being worked in many mines already, and with no unfavourable signs, even in the deepest, of its termination lower down, can surely not be called limited. That the quartz becomes, in the average, poorer in gold with increasing depth from the surface seems, however, to be the case in a great number of our deep mines, though exceptions of an actual improvement are not wanting. In fact, in many deep mines, profitable working is at present only carried on by great economy and improvements in the system of mining and the machinery, especially that for crushing the quartz, com- bined with the gold- saving appliances ; and last, though not least, by the saving and treatment of the auriferous pyrites iron, arsenical, and magnetic pyrites ores which generally appear at or beneath the water-level, and seem to increase in quantity in depth, whilst the free gold gradually decreases. Except in gold, the silurian rocks, as far as experience goes, are strikingly poor in ore-deposits of other metals. Of silver there are only known a few occurrences comparatively poor impregnations in several auriferous quartz reefs at St. Arnaud, the ore consisting of chlorobromide above, and probably of sulphide, or sulph-arsenide of silver beneath, the water-level. Copper occurs also impregnated in many quartz reefs in the form of copper pyrites, but too scantily to be of any value. Only one 62 massive lode of this ore, near the surface partly converted into oxide, carbonates, and native copper, has as yet been discovered in upper silurian rocks in the valley of the Thomson River, Gippsland. This lode stands in immediate connection with a diorite-dyke, is from 4 to 8 feet thick, and having by trial yielded from 12 to 18 per cent, of copper in the average, ought to be profitable to work, though its position in the midst of a steeply mountainous district renders carriage very expensive. Lead has not as yet been found in special deposits, but occurs as galena in most auriferous quartz reefs more or less strongly, though quite unpayably impregnated, being considered a favourable sign for gold. Iron, in the form of micaceous and brown iron-ore, prin- cipally the latter, abounds in irregular patches and impregnations ; but regular strong deposits worth working are, up to the present, not known in these rocks. The only metal, next to gold, found in quantity to be of commercial value is antimony. This occurs as grey sulphide, mostly converted into oxide near the surface, in strong veins and larger and smaller pockets, partly and more fre- quently associated with auriferous quartz reefs (Heathcote, Whroo, &c.); partly isolated (Ringwood); the upper silurian rocks having hitherto proved the most prolific. LOWER SILURIAN ROCKS. The series of specimens derived from this formation may all be classed as mechanically-formed rocks. They comprise conglo- merates, breccias, sandstones, quartz rocks (quartzite, Lydian- stone), shales (mudstones), and clay-slates, and are described in the order just given. CONGLOMERATES AND BRECCIAS. 316. SLATE-CONGLOMERATE. A base of fine-grained, soft, micaceous sandstone, enclosing rounded pieces of slate. Section 50, Spring Plains. Geological J sheet, 13 N.E. 317. QUARTZITE-BRECCIA. Very fine-grained, dark sandstone- base, enclosing larger and smaller angular fragments of very fine- granular quartzite. From a gully south of allotment 3, section A\ t Maldon. 63 SANDSTONES. 318. SANDSTONE, QUARTZ-GRIT. Pretty even-sized, rather coarse and angular grains of quartz, cemented by a very small per-centage of a base of apparently feldspathic character ; in part ferruginous. Mia-mia Ranges, sections 42 and 66, M'lvor Road, Spring Plains. 319. SANDSTONE, QUARTZ-GRIT. Larger and smaller angular grains of quartz, cemented by very little feldspathic-looking base. Talbot. 320. SANDSTONE. Medium-grained; highly quartzose and hard, resembling quartzite ; the quartz grains connected by very little siliceous cement ; shows irregular red, ferruginous patches, and is in some parts gritty. Inglewood. 321. SANDSTONE. Medium-grained; highly quartzose, the quartz grains connected by but very little feldspathic-looking cement ; in parts brecciated ; might be useful as a building stone. Loddon River. 322. SANDSTONE. Rather coarse-grained, soft and feldspathic. M l lntyre. 323. SANDSTONE. Highly ferruginous, fine-grained and mica- ceous. Talbot. 324. SANDSTONE. Very similar to No. 323. Inglewood. 325. SANDSTONE. -Very fine-grained and micaceous ; shows more or less ferruginous bands in the line of cleavage. New- stead. 326. SANDSTONE. Fine-grained, soft, and rather argillaceous ; highly ferruginous and micaceous. Loddon River. 327. SANDSTONE. Fine-grained, rather soft and argillaceous; highly ferruginous, micaceous, and slightly porous. Talbot. 328. SANDSTONE. Fine-grained, soft, very micaceous, and feldspathic ; mottled with irregular ferruginous patches ; appears to be of somewhat metamorphic character. M'lntyre. 329. SANDSTONE, QUARTZ-GRIT. Coarse-grained and highly quartzose ; the greater portion coloured brown and red by hydrous ferric oxide, and traversed by a small quartz-vein. Kingower. 330. SANDSTONE. Rather fine-grained, ferruginous, and very micaceous; small, roundish, lighter-coloured portions of appa- rently feldspathic and less micaceous character, irregularly dis- tributed throughout the mass, impart to the rock a mottled, conglomeratic appearance. Loddon River. 331. SANDSTONE. Medium-grained, minutely porous, and very feldspathic. M'Intyre. 64 332. SANDSTONE. Fine-grained, rather argillaceous, and slightly micaceous ; in part ferruginous. Mia-mia Ranges, sec- tions 42 and 66, Spring Plains. 333. SANDSTONE. Medium-grained, rather feldspathic and micaceous ; cleavage rather slaty. Kingower. 334. SANDSTONE. Very fine-grained and argillaceous, resemb- ling an indurated mudstone ; finely banded in two different directions ; one set of bands of a ferruginous character, impart- ing a concretionary appearance. Pyrenees. 335. SANDSTONE, QUARTZ-GRIT. Rather coarse-grained, and highly quartzose ; cleavage pretty even and regular. Stony Creek Reservoir, Geelong Waterworks. 336. SANDSTONE. Coarse-grained, highly quartzose, and tra- versed by quartz-veins ; resembles quartzite, but shows a cement- ing medium. Brisbane Ranges, near Geelong. 337. SANDSTONE. Medium-grained, soft, rather feldspathic, and slightly micaceous. M'Intyre. 338. SANDSTONE. Very fine-grained and tough ; siliceous, and minutely micaceous. Loddon River. 339. SANDSTONE. Very similar in character to foregoing; shows faint ferruginous bands. From between M'lvor and Sandhurst. 340. SANDSTONE. Medium-grained, rather micaceous, and slightly feldspathic ; in part ferruginous. Caliban River. 341. SANDSTONE. Very fine-grained, micaceous, and slaty ; might be called a " slaty sandstone." Mount Franklin 342. SANDSTONE. Medium-grained, and rather micaceous ; shows very regular ferruginous lines and bands, which impart to it a concretionary appearance. Bendigo. 343. SANDSTONE. Medium-grained, pretty tough, very quartzose, and slightly micaceous ; might be useful as a building stone. From between M'lvor and Sandhurst. 344. SANDSTONE. Very fine-grained, argillaceous, and slightly micaceous ; full of impressions of fossil plants (fucoids ?). Kingower. 345. SANDSTONE. Very fine-grained, argillaceous, and slightly micaceous ; texture slaty. Swiper's Reef, Maldon. 346. SANDSTONE. Fine-grained, rather soft, and slightly micaceous ; cleavage flagstone-like. Maryborough. 347. SANDSTONE. Rather soft, and very micaceous ; fine- grained, and somewhat argillaceous. From near Bacchus Marsh. 348. SANDSTONE, FLAGSTONE. Medium-grained, quartzose, and slightly micaceous ; very thin-bedded, and of the character of a flagstone. Redesdale, Campaspe River, section 40. 65 QUARTZ ROCKS. 349. QUARTZITE, QUARTZ ROCK. Coarsely crystalline-granu- lar; in parts of a gritty texture; modification of rock No. 318. Mia-mia Ranges, sections 42 and 66 ; M t Ivor-road, Spring Plains. 350. QUARTZITE, QUARTZ ROCK. Coarsely crystalline-granu- lar. Inglewood . 351. QUARTZITE, QUARTZ ROCK. Similar to No. 350, but a little more ferruginous, and, in consequence, showing some varia- tion in colour. Inglewood. 352. QUARTZITE, QUARTZ ROCK. Very finely crystalline- granular ; apparently quite dense and hornstone-like ; might furnish good grinding stones. Top of spur close to north-east corner of Mount Tarrangower Tunnelling Company's lease. 353. QUARTZITE, QUARTZ ROCK. Rather coarsely crystalline- granular, ferruginous, and in parts of brecciated appearance. Inglewood. 354. LYDIAN-STONE, LYDITE (Siliceous Slate, Kieselschiefer.) Irregularly traversed by a network of very fine quartz-veins, and more or less affected by decomposition. Loddon River, near Maldon. 355. LYDIAN-STONE, LYDITE (Siliceous Slate, Kieselschiefer} Traversed by a network of very fine, more or less ferruginous quartz- v eins. Ararat. 356. LYDIAN-STONE, LYDITE (Siliceous Slate, Kieselschiefer.} Shows a kind of rude prismatic structure. Loddon River, near Maldon. SHALES. MUDSTONES. The term Mudstone, introduced into science by Sir Roderick Murchison, is especially applicable to a kind of rock holding an intermediate position between very fine-grained, soft sandstone and soft shale, and which is very prevalent on many of our goldfields. Whilst, on the one hand, it is not firm enough and too fissile to be termed a sandstone, it is yet too arenaceous though very minutely so to be properly called a shale. It adheres strongly to the tongue, gives an earthy odour on being breathed upon, and falls in water, or on exposure to the atmosphere, more or less quickly, to a muddy non-plastic mass. It is, in fact, a stratified, somewhat indurated, mud, composed of lavigated sandstone, shale, 66 and clay-slate material, and showing generally a well-developed slaty or fissile texture. Its prevailing colour is mostly white or yellowish-white ; but darker shades of yellow, brown, red, and bluish-black, the former from admixture of hydrous ferric oxide, the latter from that of carbonaceous matter, are also not rare. A banded or mottled appearance in all the above shades of colour is not unfrequently met with. The term " pipeclay," as used by our alluvial miners in the phrases, " the washdirt rests on pipe- clay," "driving in the pipeclay bottom," &c., refers in most instances to the generally softer or friable basset edges of the beds of this rock. 357. MUDSTONE. Texture imperfectly slaty ; highly argil- laceous, soft, and minutely mottled by ferruginous and dendritic m arkings. Bendigo. 358. MUDSTONE. Argillaceous, somewhat indurated, and irregularly traversed by red ferruginous bands, causing a concre- tionary appearance ; texture imperfectly slaty. Bendigo. 359. MUDSTONE. The same in character as No. 358. Bendigo. 360. MUDSTONE. A soft white portion in contact with a more indurated, mottled, ferruginous one ; texture imperfectly slaty.- Bendigo. 361. MUDSTONE. Very soft and less argillaceous than fore- going specimens ; texture perfectly slaty ; approaching fissile. Pyrenees. 362. MUDSTONE. Very soft and friable, and marked with extreme regularity by parallel greyish-white and greyish-black bands. Bendigo. 363. MUDSTONE. Somewhat indurated, rather argillaceous, and showing pretty regular, parallel, greyish-white, grey, and narrow purple-coloured bands ; texture imperfectly slaty. Ingle- ivood. 364. MUDSTONE. Rather argillaceous, and showing pretty regular parallel, faintly-brown, ferruginous bands ; texture thin- 365. MUDSTONE. Slightly arenaceous, soft, apparently felds- pathic or like impure kaoline ; resembles decomposed elvan- dykestone. Swiper's Reef, Maldon. 366. MUDSTONE. Very soft and arenaceous. Bendigo. 367. MUDSTONE. Rather indurated and arenaceous (sand- stone-like), and densely marked by pretty regular, parallel, ferruginous bands. Inglewood. 368. MUDSTONE. Strongly indurated, arenaceous, slightly micaceous, and densely filled with ferruginous, concretionary, 67 stalk-like bodies, arranged in an imperfectly-radiating manner, which imparts to the design the appearance of coralline structure. Loddon River. 369. MUDSTONE. Argillaceous, somewhat indurated, and traversed irregularly by faint, brown, ferruginous bands ; texture slaty. Dunolly. 370. MUDSTONE. Very soft and friable ; texture slaty ; shows polished-looking slate-like faces. Lord Malmsbury Com- pany's Claim, near Malmsbury. 371. MUDSTONE. Kather indurated, argillaceous, of mottled appearance, and densely filled with small, roundish, concre- tionary, ferruginous bodies or granules, imparting to it the character of being metamorphosed ; texture slaty. Pyrenees. 372. MUDSTONE. Rather indurated and slightly micaceous, traversed very regularly by parallel, ferruginous bands. Welsh- man's Reef, Sandy Creek, near Maldon. CLAY-SLATES. 373. CLAY-SLATE. Fissile, rather soft, and shows a faint satiny lustre. Red Jacket Claim, Ballarat. 374. CLAY-SLATE. Useful for roofing purposes ; its fine dark purple colour renders it similar to the Welsh slates. Bendigo. 375. CLAY-SLATE. Thick-bedded and micaceous; cleavage very uneven ; much traversed by joints ; has the character of a strongly indurated shale. Moorabool River, between Steiglitz and Meredith. 376. CLAY-SLATE. Cleavage tolerably perfect; rather soft, and full of ferruginous oval concretions of pretty uniform size, which much resemble fossils, and are perhaps caused by meta- morphic action. Kingoiver. 377. CLAY-SLATE. Cleavage pretty regular and even ; rather soft, and regularly and delicately banded ; contains embedded cubical crystals of iron pyrites. Bendigo. 378. CLAY-SLATE. Similar to No. 377 .Bendigo. 379. CLAY-SLATE. Cleavage even and perfect; well appli- cable for roofing purposes. Slate quarries, Meredith, 380. CLAY-SLATE. Cleavage rather uneven; apparently thick- bedded ; slightly concretionary, and in cross-fracture micaceous ; has a somewhat metamorphic aspect. Maryborough. 381. CLAY-SLATE. Rather soft and dull earthy; cleavage 68 pretty regular ; full of impressions of various forms of graptc* lites. Lancefield, county of Bourke. Geological J sheet 5 S.E. 382. CLAY-SLATE. Same as No. 381 ; cleavage more perfect. Lancefield, county of Bourke. Geological J sheet 5 S.E. 383. CLAY-SLATE. Cleavage well-developed, and cleavage- planes tolerably even ; looks suitable for roofing purposes, but is too soft. Bendigo. 384. CLAY-SLATE. Thick-bedded and somewhat arenaceous, enclosing apparently some bituminous or carbonaceous matter ; cleavage very irregular and uneven ; resembling an indurated mudstone. Loddon River. 385. CLAY-SLATE. Cleavage imperfect and uneven; rather soft ; not applicable for roofing purposes. Bendigo. 386. CLAY-SLATE. Rather tough and hard ; cleavage some- what uneven, but might be suitable for roofing purposes. Bendigo. 387. CLAY-SLATE. Thick-bedded; cleavage uneven and im- perfect ; slightly arenaceous, and contains some carbonaceous matter ; full of numerous species of graptolites. Near diorite- dyTce, Tarilta. Geological \ sheet 15 N.E. 388. CLAY-SLATE. Rather soft, and cleavage pretty even; might be used for roofing purposes. Moorabool River, between Steiglitz and Meredith. 389. CLAY-SLATE. Rather soft, and cleaves unevenly. Yan- doit. 390. CLAY-SLATE. Soft and friable ; somewhat argillaceous and fissile ; has the character of a slaty shale ; shows on the face of a joint small patches of u blue carbonate of copper." Lerder- derg River. 391. CLAY-SLATE. Soft and friable, and rather fissile, resem- bling slaty shale. Yandoit. 392. CLAY-SLATE. Cleaves pretty evenly, but is too soft for roofing purposes. Bendigo. 393. CLAY-SLATE. Very ferruginous, and hard enough for roofing purposes, but cleaves unevenly, and is apparently much jointed. Bendigo. 394. CLAY-SLATE. Cleavage imperfect, and planes of earthy, dull aspect; ferruginous, and full of various forms of grapto- lites. Section 29 Spring Plains. Geological J sheet 13 N.E. 395. CLAY-SLATE. Hard, micaceous, and slightly arenaceous ; cleaves unevenly, and shows ferruginous bands of various shades of brown colour. Talbot. 396. CLAY- SLATE. Much jointed, rather hard, and cleavage very uneven. From near Newstead. 69 397. CLAY-SLATE. Rather thick-bedded, soft, argillaceous and slightly micaceous. Section 26, Spring Plains, Stone-Jug Creek. 398. CLAY-SLATE. Rather soft ; argillaceous and minutely porous ; cleavage pretty perfect and even ; slightly fissile ; full of various forms of graptolites. Shepherd's Claim, Christmas Reef, Bendigo. 399. CLAY-SLATE. Fissile, quartzose and micaceous; ferrugin- ous bands produce a concretionary appearance. Dunolly. 400. CLAY-SLATE. Soft, and highly argillaceous, in part quite steatitic ; red ferruginous bands produce a peculiar concretionary aspect; cleaves evenly, but rock apparently much jointed. Town Reef, Castlemaine. 401. CLAY-SLATE. Hard, ferruginous, and cleavage extremely uneven ; traversed by ferruginous quartz-veins. From close to a quartz reef, Talbot. 402. CLAY-SLATE, BLACK LODE-SLATE. Fine-grained grey sandstone (?) in contact with the slate ; the former rather concre- tionary, the latter slightly micaceous ; both impregnated with iron pyrites, and traversed by quartz- veins. From a quartz reef, Clunes. 403. CLAY-SLATE, LODE-SLATE, GANGUE-SLATE. Fissile, but cleaves very irregularly ; shows a weak satiny lustre ; in parts impregnated with iron pyrites, and traversed by quartz- veins From a quartz reef, Clunes. 404. CLAY-SLATE, LODE-SLATE, GANGUE-SLATE. Similar to foregoing, but slate black and carbonaceous ; impregnated with iron pyrites, and traversed by quartz- veins. From a quartz reef, Clunes. UPPER SILURIAN ROCKS. MECHANICALLY-FORMED ROCKS. CONGLOMERATES AND BRECCIAS. 405. CONGLOMERATE. Fine-grained, quartzose, more or less ferruginous sandstone base, enclosing small rounded pebbles of quartz and different rocks, and densely filled with casts of fossils. Goulburn River. 406. CONGLOMERATE, Same as foregoing. Goulburn River. 407. CONGLOMERATE. Smaller and larger rounded pebbles of quartz, slate, dykestone, Newbery gave 6310 per cent, of fixed carbon, 5 '90 of ash, 20'85 per cent, of volatile matter, and 10 '15 per cent, of water. G2 84 MECHANICALLY-FORMED ROCKS. CONGLOMERATES (PUDDINGSTONES), BRECCIAS, &c. 468. CONGLOMERATE, Puddingstone. Consists of a base of quartz-grit or small-grained quartz conglomerate, enclosing larger rounded pebbles of quartz and greenstone. Barrabool Hills, near Oeelong. 469. BRECCIA. Composed principally of silicified remains of plants and carbonaceous matter, cemented by gritty sandstone. Barrabool Hills, near Geelong. 470. SANDSTONE-GRIT. Granitic detritus,principally composed of coarse grains of quartz, smaller ones of more or less decom- posed feldspar and little mica, rather loosely cemented by slightly ferruginous, argillaceous matter. Barrabool Hills, near Geelong. 471. SANDSTONE-GRIT. Very coarse grains of quartz, feldspar, sandstone, slate, &c., cemented by an argillaceous paste ; in parts conglomeratic, through enclosed larger rounded fragments of quartz, sandstone, &c. Barrabool Hills, near Geelong. 472. SANDSTONE. Very coarse-grained, gritty, and feldspathic; very similar to No. 471, but is harder. Barrabool Hills, near 473. SANDSTONE. Very similar to foregoing ; coarse-grained, somewhat gritty, argillaceous and feldspathic ; encloses sparingly larger pebbles, and is interstratified with thin seams of what appears to be cemented granitic detritus. Barrabool Hills, near Geelong. 474. SANDSTONE. Rather coarse-grained, feldspathic, and minutely porous ; might be applicable as building stone. Barrabool Hills, near Geelong. Mr. Selwyn's Geological Note. The carbonaceous rocks of the Barrabool Hills (from which the foregoing specimens are taken) consist of a series of hard, thick-bedded, brown and grey sandstones, much jointed, and with thin veins of carbonate of lime. They alternate with shales and conglomerates, and have an average dip of E. 30 S., at an inclination of 1 in 4. Over the area com- prised between the village of Ceres and the municipality of New town and Chilwell, about 3000 feet of carbonaceous strata crop out at the surface ; the highest beds are found to the east and the lowest to the west. It is highly probable that this part of the series has been tested for coal in the Bellarine District, since an intermediate synclinal axis exists in the ground between Kensington and Geelong ; and the Barrabool Hill sandstones, 85 shales, &c., would thus be a recurrence at the surface of those bored through in the Bellarine District. The sandstones of the Barrabool Hills are extensively quarried, and used for building purposes in and around Geelong. They are variable in composi- tion and durability, and their prevailing dull, greenish-brown colour renders them objectionable for large buildings in which architectural effect is required. 475. SANDSTONE. Coarse-grained, very soft, and friable ; highly charged with carbonaceous matter ; slightly micaceous ; structure slaty. Cape Otway. 476. SANDSTONE. Rather coarse-grained, tough, and hard : thinly cleavable ; calcareous ; encloses carbonised fragments of plants. Sandford, Wannon River. SHALES. 477. SHALE, COAL SHALE. Soft and friable ; represents a but slightly indurated clay, with quite irregular cleavage ; full of remains of fossil plants. Gape Patterson. 478. SHALE, COAL SHALE. Same as No. 477. Gape Patter- son. 479. SHALE, COAL SHALE. Soft and friable ; represents a slightly indurated clay ; in parts somewhat arenaceous, and charged with carbonaceous matter ; cleavage quite irregular. From near Goleraine. 480. SHALE, COAL SHALE. Soft and friable, but some portions much harder than others ; slightly laminated ; cleavage planes uneven ; full of impressions of fossil plants (Tceniopteris Daintreei). Moe, Gippsland. 481. SHALE, COAL SHALE. Very soft and friable, and slightly arenaceous ; much charged with carbonaceous matter, and full of carbonised fossil-plant remains. Moe, Gippsland. 482. SHA.LE, COAL SHALE. Very soft and friable, and highly charged with carbonaceous matter; resembles brown coal. Jfos, Gippsland. CHEMICALLY-FORMED ROCKS. LIMESTONES. 483. LIMESTONE. Dense and argillaceous, and showing a tendency to "cone-in-cone" structure. From a half-mile soutfi of Den Hills, near Muntham. 86 ORGANIC ROCKS. 484. COAL. Of rather poor quality, and rather thinly lamin- ated ; said to come from a seam three feet thick. Traralgon, South Gippsland. 485. COAL. Impure, of a rather shaly character; hard and much laminated. Specimens of this coal analysed by Mr. Cosmo Newbery gave 1. Raw Mineral. Carbon Hydrogen ... Oxygen and nitrogen Sulphur Ash .. 66-74 4-83 5-20 1-65 21-58 lOO'OO 2. Dried Mineral. Volatile matter ... 35-74 Fixed carbon ... 42-68 Ash 21-58 100-00 The raw mineral contains about 4 per cent, of hygroscopic water. Traralgon, South Gippsland. 486. COAL. Of inferior quality, on account of its being much fractured and traversed by small veins of calcite. From near Moe, Gippsland. 487. COAL. Of good quality, but very much fractured and laminated j would deteriorate on exposure to the atmosphere. An analysis by Mr. Cosmo Newbery gave the following results : Water Volatile hydrocarbon Fixed carbon ... Ash 7-3 29-2 59-2 4-3 100-0 From the seam at Kilcunda, Jive miles from Griffith's Point. 488. COAL. Of good quality, but much fractured and lami- nated ; would probably deteriorate on exposure to the atmosphere. An analysis of the late Mr. Charles Wood gave : 28.8 56.4 4.0 10.8 100.0 From the so-called " Queen Vein" 3 to 4 feet thick, Cape Pat- terson. Volatile matter Fixed carbon... Hygroscopic water Ash 87 ROCKS OF THE TERTIARY OR CAINOZOIC AND RECENT PERIOD. According to Mr. Selwyn* the rock formations of the tertiary, including the recent period, whether regarded in their economical, physical, or geological aspects, occupy by far the most prominent place in Victorian geological history. Strata of sedimentary or volcanic origin, referable to some section of tertiary or recent time, occupy probably fully one-half, or over 40,000 square miles, of the surface of Victoria, forming deposits from a mere capping to over 300 feet thick. They are found resting unconformably on all the older formations, igneous and stratified, and range from sea-level to elevations of over 4000 feet. They include groups of strata of earth, loam, sand, clay, gravel, conglomerate, breccia, ferruginous and calcareous sandstone and grit, hard quartz rocks, marble and other kinds of limestone, and various volcanic pro- ducts, each of which has its more or less distinctive geological, palreontological, or mineral character, indicating it to be truly representative of the recognised eocene, miocene, pliocene, or pleistocene (including recent) deposits of Europe and other countries; the terms being applied here, however, simply to denote lower, middle, upper, and recent tertiaries, rather than exact synchronism with European beds, or any ascertained relative percentage of living and extinct forms in their fossil contents. The oldest beds, probably upper eocene, occur on the east shore of Port Phillip Bay, resting on granite and mesozoic carbonaceous rocks. Very fine collections of fossils, now in the National Museum, have been procured from them. The beds are chiefly composed of blue clays and marls, with septarian-limestone nodules and selenite, and generally closely resemble the eocene strata of the Hampshire -and London basins. The miocene division is chiefly represented in the marine tertiaries, extending from the western boundary of the colony to the east shore of Port Phillip Bay, being well ex- posed in the coast cliffs and river banks, and occurring sometimes, as at the Muddy Creek, near Hamilton, upwards of forty miles inland. Its upper subdivisions also occupy a long, narrow strip of coast country, nowhere, however, exceeding sixteen miles in width, between Wilson's Promontory and Cape Howe, and form cliffs on the northern shores of the Gippsland lakes, and on some of the rivers flowing into them. From the mouth of Spring Creek to the Bird Rock, fourteen miles south of Geelong, they * " Notes on the Physical Geography, Geology, and Mineralogy of Vic- toria." Intercolonial Exhibition Essays, 1866. 88 are exposed in the fine cliff sections, reaching a thickness of 273 feet, the sequence of the beds being as follows : UPPEE MIOCENE. 80 feet : Hard, thin-bedded, sandy limestone (the calcareous portion consisting almost entirely of fossils), the probable equiva- lent of the Mount Gambier series, described by the Rev. Julian Woods. MIDDLE MIOCENE. 80 feet : Soft, brown, sandy clay. 30 feet : Brown, blue, and yellow sandy clays, containing abundance of gypsum. 1 foot : Very hard crystalline sandstone. 12 feet : Brown sandy clay, poor in gypsum. 1 foot : Very hard crystalline sandstone. 5 feet : Brown sandstone, containing abundance of gypsum. 10 feet : Blue marl, containing septaria, gypsum, and iron pyrites. 8 feet : Friable thin sandstone, with thin bands of gypsum. LOWER MIOCENE. 1 foot : Very hard band of crystalline sandstone. 17 feet : Soft brown sandstone, with thin bands of harder material. 20 feet : Thin-bedded brown sandstone. 8 feet : Blue and grey friable sandstone. Of miocene age, clearly antecedent in date to the upper and middle subdivisions, are also the so-called "lower drifts" occurring near Steiglitz, at the Golden River, Tea-tree Creek, the Upper Moorabool, Parwan Creek, Bacchus Marsh, and Ballan which, though in many respects quite similar in character to, and forming in places actually, the bottom or floor of real older gold-drift, have not themselves as yet proved, nor are perhaps likely to prove, productive in gold. The deposits of pliocene and recent age, both of marine and fresh-water origin, have a far wider surface-range than the older marine tertiary deposits ; they cover these all along the eastern seaboard, and occupy also the vast extent of the Lower Murray Plains, But what renders them besides the most important divisions of the period is that they embrace the auriferous drifts, the determination of whose payable range is a matter of the utmost consequence as affecting the probable extent and produc- tiveness of the goldfields. During the progress of the late geological survey it has been clearly established that there are at least three distinct periods of deposition ; the earliest not older than pliocene, whilst the newest is probably due to causes still in operation. In absence of satisfactory palseontological evidence, these three drift-deposits have provisionally been classed as older. 89 pliocene, newer pliocene, and post-pliocene, including recent ; or as lower, middle, and upper gold- drifts. The mode of relation of these three drifts in some of our most important goldfields to more or less extensive streams of newer basalt-lava would seem to afford a ready means of distinguishing at least between the first two (lower and middle) and the upper gold-drifts ; for the former, being older than the lava, are covered by it, whilst the latter, being more recent, do in places actually overlie the lava. However, besides that this distinction is only of local application, there are also exceptions to the above relations in the neighbour- hood of basaltic craters and points of eruption that were more recently active for instance, at Mounts Franklin, Buninyong, Warrenheip, &c. Though most of the lava-flows discharged from these volcanic vents (the latter show at least four flows) are no doubt older than the upper gold-drift ; still some are certainly more recent, as they have been poured into valleys filled with this drift. A fine instance of this is exhibited at Yandoit, near Mount Franklin. Although associated basaltic flows do not therefore in all cases present a sure guide for identifying any of the three drifts, each of the latter can, however, be easily recog- nised by special characteristics of its mass, relative position, and other circumstances, as the following description will show : I. THE OLDER PLIOCENE, OK LOWER GOLD-DRIFT. The special character of this drift is that its gravelly portion- is principally composed of quartz pebbles or boulders, which, as well as the gold contained in it, are perfectly rounded or water- worn. Although it is in some places as, for instance, in the White Hills at Bendigo, the Loddon valley hills, &c. well arranged according to size i.e., from small to large, from the top downward still it is more frequently observed that though the coarsest the real boulder-drift lies at the bottom, the superincumbent portion is variously composed in different localities. In our western goldfields Ballarat, Castlemaine, Avoca, &c. it consists of layers of sand and clay, of sandy and clayey, coarse and fine gravel, and where filling deep valleys and carrying the present surface drainage channels, beds of real drift- sand are not unfrequent. In the large deposits of this drift discovered on the Tangil River, Gippsland, the pebble drift, or rounded quartz-gravel, is only a few feet thick, but covered in places by over 100 feet in thickness of an indurated, yellow or brown, very arenaceous clay, which so closely resembles the soft, yellow, silurian sandstone the rock-bottom of the district 90 that, except for its horizontal bedding, and the absence in it of small quartz-veins that are always present in the true bottom- rock, it might be easily mistaken for the latter. The predominating colours of this drift are either white or brown, or white and brown mottled, whilst the bottom layer or washdirt is often rich in a black carbonaceous clay, or shows a covering of this clay, in which remnants of trees as branches, roots, trunks, leaves, seed vessels, &c., all more or less carbonised, or sometimes wholly or partially converted into iron pyrites are often found enclosed. In some places beds of real lignite, or brown coal, have also been found above the washdirt. Layers of hard ferruginous conglomerate (see specimens in the collection), from a few inches to several feet in thickness, and requiring blasting operations in working, are hardly ever absent, especially near the bottom of the deposit, and a peculiar, extremely hard and dense siliceous cement a real quartzite is sometimes observed in cakes near and at the top along basalt escarpments, or where the drift deposit is exposed near basalt-flows. The fact that these cement cakes, which are often many feet thick, do not extend beneath the basalt, but occur only where the drift was exposed to the atmosphere through denudation of the basalt, would tend to indicate that they are, as it were, the products of local metamor- phism of sandy clay or sand, in which siliceous waters, produced through the denudation of the basalt, in connection with atmos- pheric agencies, performed important parts. Touching the mode of occurrence of the drift it is twofold : (a) As Hills, either solitary or in series, more or less con- nected, bounding gullies and flats, or more rarely rising in the centre of flats as, for instance, the White Hills, Maryborough, a hill in the Loddon River flat below Guildford, &c. Where these hills are covered by basalt, they are generally of far larger size than where exposed (Loddon valley outliers, &c.), which is owing to the protection against denudation afforded by this rock to the drift : for the mode of occurrence of the latter as hills is plainly a result of denudation, the deposit having once filled old valleys in unbroken streams ; but whilst first being indirectly raised through the formation of new valleys alongside, it was in aftertimes laterally cut into, and thus divided into parts the present hills by small gullies the present drainage channels. The rock-bottom of these hills lies, in the higher parts of the goldfields, generally high above the surface of the flats and gullies ; but it is frequently the case that, towards the lower parts, it gradually sinks lower and lower, and not only disappears beneath the surface of the flats, but runs at last actually far lower 91 than the rock-bottom of the latter above and below its limits, thereby proving conclusively that the old valleys had a steeper fall than the present ones. As regards the character of their mass, hills contain nearly always and frequently strong layers of conglomerate, whilst soft clay and sand-beds are less common. (b) As so-called Deep Leads. In this case the drift fills deep valleys and channels, which carry the present surface drainage, a mode of occurrence well exemplified at Ballarat, Bagshot, near Sandhurst, Eldorado, Beechworth,