﻿13S 



SUPPLEMENT TO THE CRAG MOLLUSCA. 



Astarte compressa, Mont. Crag Moll., vol. ii, p. 183, Tab. XVI, fig. 8 a — c. 



Localities. Red Crag passim. Eluvio-marine Crag, Bramerton and Thorpe. 

 Chillesford bed, Bramerton, Horstead, Colteshall, and Aldeby. Lower Glacial, Belaugh 

 and Weybourn. Middle Glacial, Billockby and Hopton. Upper Glacial, Bridlington. 

 Post Glacial, Kelsea Hill? 



The occurrence of this shell from its first appearance in the oldest part of the Red 

 Crag to the top of the Glacial series seems very uniform. It is particularly common in 

 the Middle Glacial sands of Hopton, where, although almost always more or less worn, 

 the valves of it occur perfect .far more frequently than do those of any other bivalve. 

 Mr. Jeffreys (' Quart. Journ. Geol. Soc.,' vol. xvii, p. 448) gives a fragment of 

 it from the Kelsea Hill gravel, which is the only instance of its occurrence known to me 

 in the Post Glacial deposits of East Anglia. 



Astarte Galeottii? Nyst. Crag Moll., vol. ii, p. 185, Tab. XVII, fig. 3 (as A. 



gracilis). 



In the list by Mr. Jeffreys ( c Geol. Journ.,' vol. xxvii, p. 13S) this Crag shell is 

 considered merely as a var. of A. compressa, from which opinion I dissent, believing the 

 two to be specifically distinct ; the Cor. Crag shell is not only different in form, but 

 when full grown it has a denticulated margin which is absent from comjjressa in all 

 stages of its existence. 



Mr. A. Bell ('Ann. and Mag. Nat. Hist.,' May, 1871) pointed out that A. gracilis, so 

 called by me, was not, according to Dr. Weichman, the same species as A. gracilis, Munst., 

 adding that the Cor. Crag shell must be referred to A. Galeotti, Nyst., which name I had 

 given as a synonym. Dr. Weichman has obligingly sent some of his German specimens for 

 examination, and I find that they are quite distinct. The shell called Galeotti by Nyst 

 certainly comes near to one of the varieties of my Crag species (fig. 3 d), but that is not 

 the general form. A shell also like this from Thorigny (in the Faluns), given to me by 

 Sir Charles Lyell, equally resembles our small variety, but it does not seem ever to have 

 attained so great a magnitude. Under these circumstances I have given the shell under 

 the name Galeotti with a doubt. 



Astarte incrassata, Brocchi. Crag. Moll., vol. ii, p. 178, Tab. XVI, fig. 6 a, b. 



Localities. Cor. Crag passim. Red Crag, Sutton. Middle Glacial, Hopton? 

 This species is in Mr. Jeffreys' list just referred to and in the ' Brit. Conch.' 



