22 Proceedings of the 'Royal Physical Society. 



son, who provisionally referred it to a genus of Lower Silurian 

 Brachiopocla, met with commonly in Russia, and called Acro- 

 treta by Professor Kutorga. It is very appropriately named 

 by Davidson Acrotreta Nicholsoni, in his paper "On the 

 Earliest Forms of Brachiopoda hitherto discovered in the 

 British Palseozoic Eocks."* Between the date of this paper 

 (1868) and the present time two more shells have been added 

 by Mr Charles Lapworth,f and this, I think, concludes the 

 molluscan fauna hitherto noticed from the rocks in question. 

 The shells referred to are Discina Portlockii (Geinitz), men- 

 tioned in a very interesting paper " On the Silurian Rocks 

 of the South of Scotland," J from the Hartfell and Glen- 

 kiln shales, and Lingula hrevis (Portl.) from the Hartfell 

 Shales. 



The complete List from the Black Shale series is 

 therefore — 



Acrotreta ? Nicholsoni (Davidson). 



Discina Portlocldi (Geinitz). 



Lingula hrevis (Portlock). 



Sij)honotreta micula (M'Coy). 



Tentaculites sp. 



A very extensive area has been traversed by Mr A. Mac- 

 conochie in making collections from the Black Shale group 

 for the Geological Survey, but no additions to this list have 

 rewarded his researches. The life appears to have been 

 almost entirely graptolitic, and in all probability the condi- 

 tions were not conducive to molluscan existence. 



In the succeeding Queensberry Grit group the impressions- 

 of Orthoceratites have been found at times, l)ut usually in too 

 crushed a condition to be recognisable. Specimens of this 

 description were met with by Mr A. Macconochie, near 

 Moniaive, when collecting in the south-west of Scotland. § 



We left the history of the Upper Silurian rocks and fossils 

 of Lesmahagow at that early point in their history, when only 

 traces of molluscan life had just been discovered by Messrs 



* Geol. Mag., 1868, v., p. 313, t. 16, f. 14-16. t Now Professor. 



X Trans. Geol. Soc, Glasgow, 1874, iv., pp. 164-174. 

 § Mem. Geol. Survey, Scotl., Ex])l. 9, 1877, p. 48. ] 



