2 



Bradford Clay and its Fossils. 



of this town. It is of very variable thickness, being seldom more than 

 a few feet, often only a few inches deep, whilst at Farleigh Castle 

 and at Tellisford it is as much as 50 feet in depth. For the benefit of 

 those who are not acquainted with the order of sequence of the Brit- 

 ish strata, it may be well to describe the position which the Bradford 

 clay occupies in the series. 1 It occurs about the middle of the 

 fossiliferous strata of this county, having immediately below it 

 the Great Oolite — then follow the Fullers' earth, the Lias, the Car- 

 boniferous limestone, Coal measures, &c, &c. 



Commencing immediately above it, we have the Forest marble, 

 Cornbrash, Oxford clay, and Kelloway rock; then the Coral rag, 

 and the associated Calcareous grit and Kimmeridge clay; the 

 Wealden beds, the Purbeck and Portland Oolites. Then commence 

 the Cretaceous group, viz : — Lower Green sand, Gault, Upper Green 

 sand, and Chalk. Above these are the Tertiary strata : and lastly 

 we have the older Flint drift, the Mammalian drift, Brick earth, 

 and the Great Northern drift. 



These strata, more than twenty in number, were (with the excep- 

 tion of the Wealden and some of the Tertiaries, which are of fresh 

 water origin) deposited very gradually, a few inches, or even less 

 at a time, at the bottom of the sea ; and although all of them may 

 not have been accumulated above this particular locality, yet all of 

 them were formed here, or in the surrounding districts subsequently 

 to the formation of the Bradford clay. There is good evidence 

 that many of the strata enumerated, were once lying above the 

 Bradford clay, on this very spot, and that they have been removed 

 by the disruption and denudation which modified the forms of the 

 surrounding vallies and hills, as their bouldered fragments may be 

 abundantly found in the drift gravel of the district. 



The question has lately been put to me " What is the age of the 

 Bradford clay ?" The answer is written on the rocks around us, — 

 nature's own stereotype, — though in language of such sublime 

 antiquity, that our limited faculties cannot grasp its full purport. 

 The strata above mentioned having been deposited to the depth of 



1 Yide Mr. Scrope's admirable description of the British strata, in the paper 

 already alluded to. 



