﻿BIVALVIA. 



15L 



Tellina Balthica, Linne. Crag Moll, vol. ii, p. 231, Tab. XXII, fig. 1. 



Localities. Lower Glacial, Weybourne, Belaugh j Rackheath, Crostwick, Spixworth, 

 and Wroxham. Middle Glacial, Hopton, Billockby and Clippesby. Upper Glacial, 

 Bridlington and Dimlington. Post Glacial, March, Kelsea Hill, Paull Cliff, Hunstanton, 

 and Nar Brickearth. 



This shell was erroneously given by me from Bramerton, where it has never occurred. 

 The Weybourne locality for it referred to the Mammaliferous Crag in the ' Crag Mollusca' 

 is the Lower Glacial sand of that place. Not a vestige of the shell has yet occurred in 

 any bed that can be shown to be as old as the Chrllesford Clay. In all the Glacial and 

 Post-glacial Beds, from the oldest to the newest, it occurs in profusion, which is the 

 character of its occurrence as a living shell. 



Tellina crassa, Penn. Crag Moll., vol. ii, p. 226, Tab. XXI, fig. 1. 



Localities. Cor. Crag, Sutton, and near Orford. lied Crag, Walton, Sutton, and 

 Butley. Fluvio-marine Crag, Thorpe, by Norwich. Chillesford bed, Chillesford. Middle 

 Glacial, Hopton and Billockby. 



This shell is abundant in every part of the Red Crag except at Walton, and in the 

 Scrobicularia beds or uppermost part of the Red Crag. In the Fluvio-marine Crag it 

 seems only to have occurred, and that rarely at Thorpe, from the bed of large angular 

 flints, at the base of which section (supposed by some geologists to be of terrestrial origin) 

 Mr. Crowfoot obtained it. I have not seen it from any locality of the Chillesford Bed 

 except that of Chillesford itself. I have not met with it from the Lower Glacial Sands, 

 but in the Middle Glacial sands it abounds, though in a more or less fragmentary 

 condition. 



Tellina lata, Gmel. Crag Moll., vol. ii, p. 228, Tab. XXI, fig. 6. 



This shell is unknown at Walton, and rare in the rest of the Red Crag, 1 but very 

 common in the Fluvio-marine Crag and Chillesford bed passim. It is not uncommon in 

 the Lower Glacial sand of Rackheath and Belaugh, and some fragments from the 

 Middle Glacial sand of both Hopton and Billockby may probably belong to it, but they 

 are not sufficiently perfect for determination. I observed a perfect specimen in Mr. 



I I erroneously stated in my paper on the "Red Crag," in the 'Quart. Journ. of the Geol. Soc.,' that 

 it was common in the Red Crag of Butley, but such is not the case although I have found it there. 



