yellow limestone, and I believe the Chalk 

 is not free from them. A little to the 

 west of D unstable considerable springs 

 of water break out on the N.W. side 

 of the Chalk hills, about the level of Dun- 

 stable. 



I believe you must be right in sup- 

 posing your yellow limestone to be quite 

 distinct from the other. From what I 

 can learn, I believe the N.W. edge of 

 the other, after running from Gunnerby 

 Hill on the E. side of the Trent, crosses 

 the H umber and runs under the Yorkshire 

 Chalk, and appears again about Castle 

 Howard, and so runs to Scarborough, the 

 Chalk in that place lapping over and ex- 

 tending further west than the limestone 1 ." 



This letter furnishes an example of the 

 detailed manner in which Cavendish con- 

 ducted his "Journeys." It contains several 



1 The last page and a half of this draft-letter 

 consists of an account of a journey made by Dr 

 Blagden from Dieppe to Paris, with details of his 

 observations on the geological features of the region 

 through which he passed. 



63 





