1 84 Kelloway Rock. 



and Bedford, north of which it covers an immense tract 

 of country, twenty miles in width, in the neighbourhood 

 of Huntingdon. Still further north it underlies the 

 great alluvial flats of Cambridgeshire, and the waters of 

 the Wash, and beyond this, in Lincolnshire, in con- 

 sequence of the gradual overlap of the Cretaceous strata, 

 the area occupied by the Oxford Clay narrows by 

 degrees. North of the Humber it is entirely overlapped 

 for a space, to reappear in Yorkshire, where it is well 

 exposed on the sea-cliffs in Filey Bay, accompanied by 

 the Kelloway Eock. 



Not the least remarkable circumstance connected 

 with the Oxford Clay is the very frequent occurrence in 

 it of this Kelloway Rock, which some persons would 

 willingly raise to the rank of an independent formation, 

 because of its palaBontological peculiarities. The thin 

 clay that occasionally lies beneath it contains a goodly 

 proportion of species also found in the Cornbrash, but a 

 greater number found in higher parts of the Oxford 

 Clay. When analysed it appears that the Calcareous 

 sandstone, called the Kelloway Eock by Smith, 1 contain* 

 not less than about 150 species, of which very nearly 

 one-half are also found in older formations, thus 

 forming a close bond of union between them. An 

 equal number passes upward from the Kelloway Eock 

 into the overlying Oxford Clay, or, if absent there, are 

 found in formations still higher in the series. 



The KeOoway Rock contains many Gryphceas 

 and Ammonites, one of which, A. Calloviensis, is 

 especially characteristic of this stratum. Several other 

 Ammonites, and Ancyloceras Calloviense, besides 

 Nautili (.ZV. hexagonus\ &c., are found in it. Bra- 



1 I believe originally 'Kelloway's Rock,' named from Kelloway, 

 who quarried it. 



