Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/402

306 irregular branching chert concretions, which sufficiently distinguish it, and, what is more important, the Neocomian 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 Belemnites 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 Oxfordian is the same species as Ter. diphyoides of the Neocomian, and, further, that those authors are mistaken who have cited Ter. diphya'' from Oxfordian beds in France. 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-France (Grenoble), a profound palaeontological one, and particularly useful among the Neocomian and Oxfordian beds, which in the Alps so often not only simulate each other lithologically, 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-France as Neocomian, he leaves unexplained the presence of Aptychus lamellosus and A. Loevis (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 considerably from specimens of ''Ter. diphyoides'' which I have found in the Neocomian of Meruet (Mont Argentine, Vaud), and from specimens in the Museum of Lausanne from Chatel St. Denis (Vaud); 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 France ''Ter. diphya'' could have been found in Oxfordian beds with Oxfordian Ammonites.

May we not in this case revert to the opinions of the author of the Paleontologie Frangaise (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.

In connexion with Mr. E. Tawney's interesting communication, I would mention that I have recently had occasion to converse with