1863.] DAVIDSON NOVA-SCOTIAN BRACHIOPODA. 169 



bable that a further search among the Lower Carboniferous rocks of 

 that country may bring to light a larger number ; and, indeed, there 

 existed in the collections above named specimens of one or two more 

 species, which I could not venture to determine on account of their 

 imperfect preservation. 



As a rule, the Brachiopoda of Nova Scotia are small when com- 

 pared with the same species from some other countries — a result 

 perhaps of the conditions, already described, under which the beds 

 were deposited. I must not omit to mention that there occurs no 

 marine limestone, with which Dr. Dawson is acquainted, over the 

 productive coal-measures, except at one place, Wallace, where there 

 is a thin band of limestone in the upper coal-strata, which contains a 

 Productus ; but this was found in too incomplete a condition to admit 

 of determination. 



1. Tehebeatula saccttltis, Martin, sp., 1809, and varieties. PI. IX. 

 figs. 1,2, 3. 



Terebratula elongata and T. sufflata, De Verneuil, in Sir C. Ly ell's 

 Travels in North America, vol. ii. p. 220, 1845, and in Dawson's 

 Acadian Geology, p. 219, fig. 27, 1855. 



All the Terebratulce from the Lower Carboniferous strata of Nova 

 Scotia that have been forwarded to me by Dr. Dawson, as well as 

 those brought from that country by Sir C. Lyell, are variable in shape, 

 but are evidently referable to a single species. M. de Yerneuil has 

 identified this shell with Schlotheim's T. elongata, and mentions that 

 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. elon- 

 gata 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 Car- 

 boniferous 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. Jiastata 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. Jiastata, 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 

 Terebratulce. 



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 num- 



