154 INVERTEBRATA. 



Hamites ? 



Fragment of a small round-sectioned Hamite, with prominent 

 rounded ribs, which are mostly simple — only one of them is seen 

 to bifurcate. They are separated from one another by more than 

 their own breadth. 



Locality. Upware (Coll. Mr J. F. Walker, of York). 



?Gervillia solenoides, Defrance. 

 Locality. Upware (Coll. Mr J. F. Walker, M.A.). 



Terebratula ovoides, Sowerby. 



Variety rex, Ray Lankester. 



(Plate viii., fig. 10, a, b.) 



Terebratula ovoides, Sby., Min. Con., t. 100, p. 227. 

 Terebratula rex, E. Ray Lankester, Geol. Mag., 1870, p. 410. 



A species to which much doubt and considerable interest 

 attaches, on account of its wide distribution in boulders, while it is 

 unknown in situ. It is a large species, with a very characteristic 

 medial ridge along the large valve, and with the dorsal valve fre- 

 quently flattened in the specimens from Upware, S. Willingham, 

 and Herrimere. 



The lateral beak ridges may be sharp and the lines of growth 

 may become developed into imbricating squama?. 



Sowerby's original specimens were from a sandstone boulder, 

 "a sandstone containing green sand " found in Suffolk (T. ovoides 

 and T. lata, Sow., Min. Con., I. p. 227), and I have found it in a 

 hard green-grey sandstone boulder at South Willingham in Lin- 

 colnshire, also at West Dereham, near Downham Market. 



But its most interesting occurrence is at Herrimere, N. of 

 Upware on the Cam, for here it occurs associated with other 

 fossils whose age can be determined, namely, Lower Cretaceous. 

 I have already (see ante, p. 35), given my reasons for believing 

 that this occurrence at Herrimere is not in situ, as has been stated 

 elsewhere (Geol. Mag., 1870), nor of Jurassic age, but that it is 

 really a boulder of Neocomian sandstone. 



