Dear Darwin—

Any letters directed to the Survey—at 6 Craigs Court Charing X—will always find me—²

Gryphaea orientalis³ is from the Southern India* beds & is Cretaceous— Probably upper GreenSand.

* Verdachellum⁴ not Pondicherry in this case.

I shall look out for the Copiapo Avicula which had escaped me.⁵

D’Orbigny & Von Buch no doubt mean the same thing.⁶ Exogyra or Gryphæa couloni is a characteristic Neocomian fossil. Von Buch’s conclusion of the beds forming a passage from the oolites to the Chalk is exactly what I believe to be true. Von Buch wrote before the “Neocomian” was investigated.⁷

The relative positions would be as follows:

D’Orbigny probably looks on the Amer beds to be purely “Neocomian” since he holds the doctrine of definite divisions or formations everywhere.

Ever, most sincerely | Edward Forbes