159 



aceous colour was discharged by heat. Hence I concluded that such beds very 

 probably would contain fossils. So I set Ruthven to work, and he found 

 graptolites and fucoids not far from the spots I pointed out to liim, but he found 

 no shells nor crustaceans. Since then I have had some doubt about the age of 

 the Skiddaw group. It is of enormous thickness, and may well contain one or 

 two groups of very distinct epochs both physically and palseontologically. 



(4.) When you are seeking Skiddaw Slate, I recommend you to take up your 

 quarters at the inn at the foot of Crummock Water. I should have been there 

 now but for an attack of English cholera * * I hope [soon] to get to Dent, 

 and thence to the locality of the Lakes, where Professor Rogers has engaged to 

 meet me. 



* * Hammer well the gritty rocks which appear in the several deep ravines 

 which run up the mountains on the left side of the road from Scale Inn to 

 Buttermere. They promise well for fossils. I never examined tliem for fossils 

 in 1823 and 1824, because I foolishly thought they were all below the region of 

 animal life. At that t'mte I had not quite learned to shake off the Wernerian 

 nonsense I had been taught. 



There is a hill somewhere in Cumberland called Whiteless, I think near 

 Crummock. I never heard of its fossils, neither do I know anything of the 

 "flaggy beds of Balmae" you mention in your letter. Pray write to me on this 

 subject at "Dent, near Kendal," the best address I can give you. 



Visit Black Combe in the S. W. comer of Cumberland. This is of Skiddaw 

 Slate brought up by enormous dislocations, and its ravines are of good promise. 

 To the south it is overlaid by the Green Slates and Porphyries, well marked, 

 but of degraded thickness. And over the Green Slates you have, in the 

 S. Western extremity of Cumberland the Coniston Limestone, &c., and some 

 appearances in the cleavage planes which I think defy the mere pressure theory. 

 That there has been enormous compression along the cleavage planes no one 

 can doubt when the fossils are flattened and distorted. But they are not always 

 flattened and distorted — you have to account for unflattened concretions marking 

 (tho' rarely) the average direction and dip of the cleavage planes. You have to 

 account for the frequent change of cleavage, and if, when the * * tchange 

 of conditions of pressure indicated in the sections, and you have to account for 

 a second cleavage plane among beds that are by no means crystalline. 



I was, most unfortunately, away when Sorby read his paper at Cheltenham. 



(6.) Visit Coniston, and look at the enormous dislocations, etc. Mr. James 

 Marshall would help you to localities. You have there, as also at Broughton- 

 in-Furness, which you pass through on your way from Black Coomb to Coniston,) 

 the Coniston Limestone and the Coniston Flags, or the Coniston Grits which 

 form the boundary between a Lower and an Upper system — by whatever name 

 you choose to call them. 



t This part of the letter was quite illegible. 



