306 PKOCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 26, 



irregular branching chert concretions, which sufficiently distinguish 

 it, and, what is more important, the IS^eocomian does not occur 

 within several miles. It is almost unnecessary to add that the blocks 

 are not transported ; they are all Bajocian or Oxfordian, and lie 

 immediately under the escarpments from which they are derived. 



The accompanying fossils are not numerous; I only found Belem- 

 nites hastatus and other Belemnites. 



We have thus a clear case of the occurrence of this remarkable 

 form of Brachiopod in the Oxfordian limestones of the Alps. 



I have wished to record this, because the high authority of Prof. 

 Hebert has been lent to the view * that Ter. diphya of the Ox- 

 fordian is the same species as Ter. diphyoides of the Neocomian, 

 and, further, that those authors are mistaken f who have cited Ter. 

 dipTiya from Oxfordian beds in Prance. It is against the latter 

 reasoning that we may here protest. I in no way wish to throw 

 doubt on Prof. Hebert's criticisms on M. Lory's work on the beds at 

 Porte-de-Prance (Grenoble), a profound palaeontological one, and 

 particularly useful among the Neoeomian and Oxfordian beds, 

 which in the Alps so often not only simulate each other lithologi- 

 cally, but whose fossils, in a fragmentary condition, are sometimes 

 hard to distinguish. 



But, as he himself admits, in counting all the beds with Ter. diphya 

 at the Porte-de-Prance as Neoeomian, he leaves unexplained the 

 presence of Aptychus lamellosus and A. Icevis (Oxfordian species) 

 and the breccia with Corallian fossils. But at any rate it is not 

 shown, because Ter. diphya does not occur in the Oxfordian at 

 Grenoble, that it does not occur in that formation elsewhere. 



I may remark that my specimen of Ter. diphya differs consider- 

 ably from specimens of Ter. diphyoides which I have found in the 

 Neocomian of Meruet (Mont Argentine, Yaud), and from speci- 

 mens in the Museum of Lausanne from Chatel St. Denis (Yaud) ; 

 but without a series of specimens it would 'be impossible to assert 

 that they are distinct species. Prof. Hebert has not apparently 

 had Oxfordian specimens to compare with the Neocomian ones, 

 as he does not admit that in Prance Ter. diphya could have been 

 found in Oxfordian beds J with Oxfordian Ammonites. 



May we not in this case revert to the opinions of the author of 

 the Paleontologie Prangaise (especially as Prof. Hebert's arguments 

 almost seem to exclude one another), and hold that different species 

 are found in the Jurassic and Cretaceous periods. 



At all events we have shown that Ter. diphya does occur in the 

 Jurassic period. 



Note by Mr. Davidson. 



In connexion with Mr. E. Tawney's interesting communication, 

 I would mention that I have recently had occasion to converse with 



^ Vide Archives des Sciences Naturelles, p. 303, Aug. 1866. Geneva, 

 t Bull. Soc. Geol. de France, ser. ii. vol. xxiii. p. 529. 

 I Ibid. vol. xxiii. p. 581. 



