330 PROCEEDINGS OF THE GEOLOGICAL SOCIETY, 



Pholades, it would not be easy to fix upon a place in the Red Crag 

 where the Testacea are on the spot where they lived*. We meet 

 everywhere with finely comminuted shells and fragments of shells, 

 with here and there a band of more perfect specimens, or a few such 

 specimens dispersed amongst the comminuted fragments. Mr. Searles 

 "Wood, however, considers that at Walton the conditions were such 

 that many of the Crag Testacea lived on that spot. Notwithstand- 

 ing the great number of shells occurring in the Red Crag, the 

 abounding and characteristic shells consist of a few species only, 

 and the larger proportion are more or less rare. Some species 

 occur in countless numbers, such as Cardium edule, Pectunculus 

 glycymeris, Tellina ohliqua, T. crassa, T. proitenuis, Mytilus edulis, 

 Peeten opercularis, Maetra solida, M. arcuata, Cyprina islandica, 

 Ludna borealis, Purpura lapillus, Trophon antiquum, Nassa granu- 

 lata, N. reticosa ; while of many only a few specimens have been 

 found, and of some only one or two specimens. In places, especially 

 as we recede from the centre of the district, the beds become almost 

 devoid of shells, or they occur only in patches. This may be partly 

 owing to the original absence of shells, but it may also be due to 

 the removal of the shells by percolation of rain-water through the 

 beds ; for at jjlaces where the beds are consolidated by iron, casts of 

 shells are occasionally met with, as in some pits between Woodbridge 

 and Grundisburgh and elsewhere. 



Mr. Searles Wood has given all the species he has procured from 

 the rich localities of Sutton, Waltonf, Bawdsey, Foxhall, and New- 

 bourne. These localities are indicated by initials in the lists of Red- 

 and Norwich-Crag fossils ; and therefore separate lists are not re- 

 quired. I have added some other localities. 



Although some species are common throughout, there are many 

 which have only a limited distribution, and which give to various 

 localities their peculiar assemblages. This will be evident from the 

 general Kst at the end, as well as from the following local lists of 

 specimens, formed by me during occasional visits to the district. 



From the pit near the Builey Oyster Inn. 



Astarte Basterotii. Mya arenaria. 



compressa. Mytilus edulis. 



OmaUi. Nucula Cobboldiie. 



Cardita senilis. nucleus. 



Cardium angustatum. Peeten opercularis. 



decorticatum. Saxicava arctica. 



edule. Solen siliqua. 



Corbula striata. Tellina crassa. 



Cyprina islandica. lata. 



Diplodonta astartea. obliqua. 



Loripes divaricata. praitenuis. 



Maetra ovalis. Dentalium costatum. 



* Mr. A. Bell has obligingly given me a list of 54 species of Red-Crag shells 

 which he has found double. They are marked d in the general list. 



t See also Mr. Wood's separate list from Walton in Quart. Journ. Geol. Soc. 

 vol. xxii. p. 542. 



