1852.] CLARKE ON THE DISCOVERY OF GOLD. 131 



the mica-schist reaches about four miles to the south of its boundary 

 westward, thus bringing the mica-schists of Ben Lomond on the line 

 of the green slate of Loch Chon * . I presume that to this is owing 

 Sir R. Murchison's allusion to the "pebble-beds in the chlorite schist 

 of Ben Lomondf." The beds so mentioned are obviously those slaty 

 conglomerates with quartz-pebbles which I have just described as form- 

 ing part of the chloritic or green slate series, which reach the western 

 flank of Ben Lomond, but cannot be considered as forming part of that 

 hill. I ascended Ben Lomond from Rowardennan, passing all the way 

 over mica-schist, and MacCulloch expressly states that the whole 

 mountain consists of micaceous sehist|. 



The chloritic or green slate is a truly stratified sedimentary forma- 

 tion, in which the bedding is distinctly seen to be traversed by the 

 planes of slaty cleavage. Moreover, it is not the lowest of the sedi- 

 mentary formations of the district ; it is therefore important that it 

 should not be confounded or coupled with the mica-schist of Ben 

 Lomond, a foliated rock of crystalline origin, in which there is only 

 one set of divisional surfaces, namely those of foliation. The distinc- 

 tion between these two classes of rocks — the stratified slates traversed 

 by cleavage, and the foliated schists without any second set of divi- 

 sional planes — is one of the most important in geology, and cannot 

 be overlooked without leading to hopeless confusion. 



2. On the Discovery of Gold in Australia. 

 By the Rev. W. B. Clarke, M.A., F.G.S, 



[Abstract.] 



In April 1841, Mr. Clarke undertook his first journey of exploration 

 from the east coast of Australia to the westward, in the parallel of 

 Port Jackson. On that occasion he became first acquainted with the 

 geological position of the Carboniferous series of New South Wales 

 with respect to the older rocks composing the axis and western flank 

 of the great chain called the Blue Mountains, which also, in conse- 

 quence of their extension N. and S. through many degrees of latitude, 

 have been appropriately denominated " the Australian Cordillera." 



Although, on the occasion alluded to, says the author, my obser- 

 vations were made without much precision, I nevertheless became 

 aware that the axis consisted of elevated schists of various kinds 

 parallel with the meridian, together with some limestones, and that 

 granitic rocks of a younger epoch had intruded into them, and were 

 accompanied by dykes of quartz. The presence also of greenstones, 

 diorites, syenites, porphyries, basalt, and other igneous products was 



* Since the above was written, Mr. Pratt has informed me that a considerable 

 mass of porphyry rises through the mica-schist a little to the north of Inversnaid. 

 Probably the disturbance mentioned in the text is caused by the eruption of the 

 porphyry.— [March 23, 1852.] 



t Quart. Journ. Geol. Soc, vol. vii. p. 169, 



X Trans. Geol. Soc. vol. ii. p. 446, note. 



K 2 



