THE OOLITES. 135 



and is seen between Scarborough and Weymouth. 

 It is evidence oi a change in the tilt of the sea- 

 bed, which makes a break in the succession of 

 the strata. 



Upper Oolites. 



There is no break in the order of succession 



of the Oolitic rocks above the Cornbrash, which 



ild divide them into Middle and Upper Oolites. 



The diff - in mineral character between the 



several beds are such as may be attributed to 



changes in level of the old land from which the 



ments were derived, which removed the source 



of the deposited material from time to time, to 



The firs I of such an upheaval is seen 



in the Kell way Rock % which forms concretionary 



sandy beds, and ye. low sands and limestones So 

 feet thick on the Yorkshire coast. It is said to 



occur in Bedfordshire. It is named from occur- 

 tt Kelloway Bridge in Wiltshire. This dis- 

 tribution may be connected with proximity to the 

 ndip ridge in the latter case, and connected 



with the Pennine chain in the former. The con- 

 ditions which produced the Stonelield slate prob- 

 ably produced the Wiltshire Kelloway rock ; and 

 the conditions of the sand beds in the Yorkshire 

 Lower Oolites are approximated to by the York- 

 shire Kelloway rock. This deposit is more im- 

 portant in France. 



The Oxford clay is manifestly the consequence 

 of a depression which prevented the coarse sandy 

 sediment from reaching so far out from its source 

 as in the previous age. This clay, which is 170 

 feet thick in Yorkshire, and 600 feet thick in 

 Dorset, is therefore superimposed upon the 



