FOUND NEAR BLACKPOOL. 



129 



No. 4. — This consists of a brown clay, rather darker in co- 

 lour than deposits Nos. 1 and 2 before described, and mingled 

 with many stones stuck into it in all directions, some standing 

 on their edges, others on their sides, and some again on their 

 flat surfaces. The rocks are very numerous, and in the lower 

 part of the cliff, below the Royal Edward, constitute fully 

 one-third of the whole mass. Their average size is greater 

 than in any of the other deposits, one specimen, a greenstone, 

 now lying on the beach, evidently derived from this deposit, 

 weighing nearly three tons. More than one-half of the whole 

 of the stones are angular, others are partly angular, and few 

 are rounded. Scarcely a slate, or carboniferous rock of six 

 inches in diameter, can be found without some marks of striaa 

 upon it. These run nearly always parallel to the major axis 

 of the stone. The hard greenstones and porphyries do not so 

 frequently shew striae as the other specimens do. The kind 

 of rocks found in this deposit is difficult to get at by counting 

 in the cliff, but 100 specimens each of which was not less than 

 the size of my fist, taken promiscuously from the shingle lying 

 on the beach below, and which had, beyond doubt, been 

 derived from the cliff, were as follows : — 



New red sandstone 1 



Carboniferous series— 10 limestones and 4 gritstones 14 



Silurians and slates 49 



Granites, greenstones, porphyries, &c 36 



In the till found in the neighbourhood of Manchester, spe- 

 cimens of magnesian limestone and new red sandstone are met 

 with. At Blackpool, in that deposit I have not yet met with 

 a specimen of the former rock, but many of the latter, and 

 one of the permian conglomerate, have been found. An inte- 



the bed of clay No. 2, just above the bed of silt at the south end of the arch 

 below the Royal Edward, is, for the thickness of about 10 inches, quite paved 

 with stones, when compared with the average quantity found in the deposit. 

 The bed of silt appears to form the upper boundary of the stony till next 

 described, and, like that deposit, is only exposed to a limited extent. 



S 



