Mr. S. V* Wood's Catalogue of Shells from the Crag, 253 



* This may be only a giant monstrosity of the obsoletus. I have only one 

 specimen. 



t These, like our recent British species, are not well defined; no dependence 

 can be placed upon them. 



% Only one valve, and that imperfect. 



§ This is variable in shape, thin, often compressed and broken ; my specimens 

 vary in size from four inches longitudinal diameter to young ones of less than a 

 line. Von Buch, in his Monograph of Terebratula, published in the Geol. 

 Trans, of France, part 3, has at p. 222 given as syn. to T. gigantea, Schlott., 

 T. bisinuata, Desh., Coq. foss. des Env. de Paris, t. 65, f. 1, T. variabilis, Sow., 

 Min. Con., t. 576, but 1 believe these two last to be different shells ; reasons for 

 thinking so shall be given in my general descriptions. 



