6Q Dr. Woolacott — A Raised Beach in Durham. 



deposit, which is at least 15 feet thick/ consists of two parts, which 

 are best seen on the north side of the path, a lower one of loose 

 sand and large pebbles, and an upper of horizontally-bedded and 

 firmly-calcreted conglomerate. In the lower layers numerous bored 

 stones occur. It contains, along with other rocks, numerous 

 large and small fragments of Magnesian Limestone, which are bored 

 by Saxicava (the shells of which sometimes occur in the holes), and 

 by Cliona and Polydora. Quite a considerable proportion of this 

 division of the deposit is formed of these bored pebbles. (3) Also 

 in the lower part numerous specimens of small and large, whole and 

 broken, shells occur, sometimes with their colour and markings 

 beautifully preserved. They include many of the common shells 

 of the present seashore — the periwinkle and the limpet, etc. — and 

 as far as the fauna has been examined there is nothing to show that 

 the climate was different from that of the present day.^ Foraminifera 

 also occur in the sand. The species of MoUusca occurring in the 

 deposit include : — ^ 



Littorina littorea Buccinum undatmn. 



Littorina rudis Cyprina islandica 



Littorina obtusata Mytilus edulis. 



Patella vulgata Ostrea sp. 



Purpura lajoillus Rhynchonella psittacea. 



Saxicava sp. 

 The commonest species are Littorina obtusata, Patella vidgata,. 

 and Littorina littorea. It is a typical littoral fauna with the 

 exception of the Rhynchonella, of which one specimen of a dorsal 

 valve has been collected. 



In the upper cemented part the shells are scarcer, but some, 

 including one or two whole Patellas, can be seen in the face of the 

 conglomerate. A portion of the shell of a Pecten was collected from 

 the upper beds. This part of the deposit is more difficult to properly 

 examine. The shells are not so clearly seen nor so well preserved nor 

 so easily extracted.^ The strongly calcreted nature of this con- 

 glomerate, and the fact that it contains fewer bored rocks and shells, 

 are of interest, because it is the more usual type of the deposit to the 

 north and south of Basington. The beds at this j)oint appear to 

 have been laid down in a sheltered bay under fairly tranquil 



1 About 10 feet can be clearly seen in the section, but its thickness (allowing 

 that the platform runs back horizontally) has been proved by a cutting made 

 in the face above it to be 15 feet. The bedded gravels are this thickness, 

 being overlaid by a few inches of soft sand containing shell fragments, above 

 which is a reassorted boulder clay. Calcreted gravels with a level upper 

 limit can be seen in the railway cutting above at about 90 feet. The writer 

 is of the opinion they are marine, although it is difficult to prove this ; it is 

 also uncertain whether they are contmuous with the gravels and sands below. 



^ A collection of shells from this deposit has been placed in the Sunderland 

 and Newcastle museums. 



^ My determination of the forms has in most cases been verified by 

 Dr. Trechmann or Mr. Iredale, of the British Museum. 



* At one part two or three shells of Helix are cemented in. 



