22 PEOCEEDINGS OF THE GEOLOGICAL SOCIEXr. [I^OV. 22, 



others ; but, from the fact of the matrix in which they were im- 

 bedded being harder than the sand which filled the shells, I found it 

 impossible to obtain perfect specimens. The upper part of this fossil 

 bed abounded in Mactra ovalis, a few having the valves united, 

 while the lower part yielded great numbers of Tellrna ohliqua, many 

 of which also had their valves united. The species which I collected 

 here were — 



Trophon antiquum. Mactra ovalis (abundant). 



Turritella communis. Tellina obliqua (abundant). 



Mytilus edulis. Mya truncata (abundant). 

 Modiola modiolus. 



Between this pit and Sudbourn Church loose sands occur. These 

 appear to crop out from beneath the Mya-bed. 



At the bottom of the vaUey the Coralline Crag may be seen in a 

 pond, and several pits have been worked in that stratum on the side 

 of the adjoining hill. But there is one remarkable pit near the top 

 of the hill, due north of .v in Ox Covert, which is referred to by Mr. 

 Prestwich in his list as consisting of Coralline Crag capped with the 

 Bed Crag, and which appears to deserve description. 



The overlying deposit, 15 feet thick, I believe to be riot Bed Crag, 

 but a shoal-deposit derived from the Mya-bed. The appearance of 

 the deposdt differs considerably in colour and texture from the un- 

 doubted Bed Crag of Butley and Chillesford, the nearest points at 

 which I saw it ; and while many of the commoner shells of the Bed 

 Crag are at this place rare or altogether absent, those of the Mya- 

 bed are in profusion; above all Mactra ovalis, the common shell 

 hereabouts of the upper part of the Mya-bed, forms its chief ingre- 

 dient. The Coralline Crag at this spot attains a higher level than 

 usual, which I doubt not was the cause of this remarkable accumu- 

 lation of dead shells, washed together during the formation of the 

 Mya-bed. The species which I noticed in this crag were — 



Mactra ovalis (in extreme profusion). Mya truncata (equally abundant). 

 Tellina obliqua (extremely abundant). Mytilus edulis (common). 

 prsetenuis (abundant), Trophon antiquum (rare). 



There is a resemblance between the species of this bed and of 

 that already described as occurring in the upper part of the Chilles- 

 ford Bed-Crag pit, at a level a little below the Mya-bed. 



Crossing the hill, the Chillesford loam is seen near a farm-house, 

 and the sands beneath it in the side of a lane near the bottom of 

 the hill. The Coralline Crag is dug in an adjoining pit. 



Crossing the valley, I met with a bed of sand covering Coralline 

 Crag, the surface of which was eroded into hummocks. The place 

 is on the same line of country as the pit mentioned by Mr. Prest- 

 wich on the north of Perry Parm-house, where he saw the surface 

 of the Crag " strongly indented by drift sands and gravel." 



This sand appeared to differ from that which I had hitherto 

 noticed as underlying the Mya-bed, and which I had just seen on 

 the opposite side of the valley. It contained a few flints of con- 

 siderable size, and the herbage which covered it was chiefly heath. 



