468 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 2, 



exhausted, I am not very sanguine that the sources hitherto dis- 

 covered will prove productive. I believe, however, that beyond the 

 Vaal River the ore is in considerable abundance, but up to this time 

 I am not aware that any attempts have been made to develope a 

 trade in that valuable metal from the inland quarter in question. 



May 2, 1855. 



W. Foster White, Esq., C. S. Mann, Esq., L. Barrett, Esq., and 

 J. D' Urban, Esq., were elected Fellows. 



The following Communications were read : — 



1. On the Anthracitic Schists and the Fucoidal Remains 

 occurring in the Lower Silurian Rocks of the South of 

 Scotland. By Professor R. Harkness, F.G.S. 



The Lower Silurians of the South of Scotland, as shown by other 

 authors*, constitute the whole of the mountainous region which, 

 lying south of the Firths of Forth and Clyde, forms the Southern 

 Highlands of Scotland, except a small patch at the eastern extremity 

 of Kirkcudbright Bay, which appertains to the Upper Silurians f. 

 These Lower Silurians have a prevailing inclination towards the 

 N.N.W., and along their northern margin we have the highest strata 

 developed. At the north-western extremity of the range, near Gir- 

 van in Ayrshire, these higher beds consist of limestone and sand- 

 stones, abounding in fossils characteristic of the Llandeilo portion of 

 the Lower Silurians. Towards the south deeper-seated strata occur ; 

 and as we find no traces of limestone beds in these, fossil remains 

 become rare, the deposits consisting principally of sandstone, with 

 some shales. Among these, however, under certain circumstances, 

 organic remains are met with, more particularly as we approach the 

 lowest portion of the formation. 



A locality where these deep-seated strata are well seen is in Glen- 

 kiln J, in the parish of Kirkmichael, about nine miles north of Dum- 

 fries. Commencing at the entrance of the glen, we find exposed, in 

 the course of the Glenkiln Burn (see fig.) underneath the manse of 

 Kirkmichael, a small patch of hunter-sandstone (?) conglomerate {a) 

 abutting against a purple sandstone (i), which forms the lowest 

 portion of the Silurian strata here seen. Similar sandstones or grits 

 (i) make their appearance higher up the stream, and, although par- 

 tially covered with gravel, form the bed of the brook until we reach 

 a spot known as Lamb-foot. 



Besides purple grits, some of which contain quartz fragments, 

 bluish-grey grits occur, and with these are associated purple and 

 greyish indurated shales. 



* See Nicol, Quart. Journ. Geol. Soc. vol. iv, p. 204, &c. ; J. C. Moore, ibid. 

 vol. V. p. 7, &c. ; Murchison, ibid. vol. vii. p. 139, &c., and ' Siluria,' p. 149. 

 t See Quart. Journ. Geol. Soc. vol. vii. p. 46, &c. ; and vol. viii. p. 393. 

 X Ibid. vol. vii. p. 49, and vol. viii. p. 393. 



