290 THE CARBONIFEROUS SYSTEM. 



a ' gibbous variety of the preceding one ' is referable to T. sufflata 

 of the same author. 



" During a lengthened examination of T. hastata and T. sacculus 

 from the Carboniferous rocks of Great Britain, as well as of T. elongata 

 and T. sufflata from the Permian strata of the same kingdom, I was 

 led to the conclusion that the specific identity of T. sacculus and T. 

 sufflata was clearly established ; and, when treating of the Carboniferous 

 T. hastata and of the Permian T. elongata, I observed that, although 

 it was an unquestionable fact that some specimens of these two so- 

 called species could not be distinguished, more difference is shown 

 between the greater number of T. hastata and T. elongata, and that 

 the strong resemblance appeared to be the exception. It must also 

 be allowed that it is often impossible to distinguish certain examples 

 of T. sacculus and of T. hastata, which forms appear to merge the 

 one into the other, and that the same may be said sometimes with 

 reference to T. sufflata and T. elongata. All this proves how inti- 

 mately connected are the British forms of Carboniferous and Permian 

 Terebratulx. 



" But to return to the Nova-Scotian specimens, I could not perceive 

 in any of them the wide and gradually depressed or shallow sinus, 

 which, in the larger valve of all well-shaped examples of T. elongata, 

 commences towards the middle of the valve and extends to the front, 

 and which produces in the frontal margin a convex curve. In nearly 

 every specimen the ventral valve is uniformly convex or but very 

 slightly depressed near the front, as is the case with the larger number 

 of T. sacculus and of its synonym T. sufflata. I think, therefore, that 

 it will be perhaps preferable to refer the Nova-Scotian Terebratulas, 

 to Martin's T. sacculus ; and in this view I am supported by Professor 

 De Koninck, notwithstanding some examples may resemble certain 

 specimens of T. elongata, T. fusiformis (Vera.), or T. hastata. The 

 largest specimen I have seen was not quite an inch in length, and the 

 greater number were much smaller. The interior, with its perfect, 

 short, simple loop, is often found, and is exactly similar to the one 

 we find in Martin's species. Sir C. Lyell mentions that he obtained 

 this shell at Windsor, Brookfield, Shubenacadie, Gay's River, De Bert 

 River, Middle River, and Cape Breton. Dr Dawson obtained it in 

 the same localities, to which he has added Pugwash, East River of 

 Pictou, Lennox Passage, etc. 



"Athyris subtilita, Hall, 1852 (Fig. 88, a, b, c). 



" Athyris subtilita, in Howard Stansbury's 'Exploration of the 

 Valley of the Salt Lake of Utah,' p. 409, pi. 2 (figs. 1, 2). 



" The Nova-Scotian specimens all appear to be small in size, but are 



