president's address. 561 



The following fossils have been recorded by Mr. R. M. John- 

 ston* : — 



Annelida. — ScoUthus Tasmanicus. 

 Trilobita. — Conocephalites Stephensi. 



Loganellus or Conocejyhalites. 



Bathyurus f?) sp. 



Asa^ihus sp. 



Dikelloce'plialus Tasmanicus. 

 Brachiopoda. — LepUnna sp. 



Orthis triangularis, (?) Sow. 

 Lamellibranchiata. — Gen. ? sp. 1 

 Gastropoda. — Ophileta spp., K. Etheridge, jim., Proc. Roy. Soc. 



Tasmania, 1863, t. 2, figs. 13 and 14. 

 Pteropoda. — Tentaculites sp. 



Mr. Etheridge expresses the following opinion with regard to 

 their geological age : — 



" Accepting therefore the determination of the foregoing 

 trilobites as approximating to the truth, it appears more than 

 probable that the age assigned to the fossils from the Caroline 

 Creek beds by Messrs. Etheridge and Lesquereux is correct, and 

 that this may be looked upon as that of the Lingula flags or 

 Menevian beds of Great Britain and the Potsdam sandstone of 

 North America."! 



Siumnary of Cayyibrian Period. — The superficial area occupied by 

 the Cambrian rocks in South and West Australia and Tasmania, and 

 their thickness, is considerable, but has not been measured as yet. 



They were laid down in seas of moderate depth, as proved by 

 the current-bedded sandstone at Ardrossan, the beds of con- 

 glomerate at Mount Lofty and in the Macdonnell Ranges. 



The ripple-marked quartzites of the Mount Lofty district, if 

 they belong to the Cambrian rather than the Lower Silurian, also 

 of course imply deposition in shallow water. The granite and 



^ Loc. cit. pp. .33, 37, 38. 

 t A Description of the Remains of Trilobites from the Lower Silurian 

 Rocks of the Mersey District, Tasmania, by R. Etheridge, Junr. Papers 

 and Proc. Roy. Soc. Tasmania, 1882, pp. 150-163. 



