222 THEORY OF DEGRADATION. CHAP. xv. 



the solid rocks do not belong to one creation! and 

 behold, they still exist. The animal whose shell they 

 name Nummulite still lives in the Mediterranean. The 

 Pentacrinite lives in the West Indian seas and in the 

 bay of Dublin. . . . Your ' Theory of Degradation ' is 

 at least a very ingenious piece of pleading ; but if I am 

 right in supposing that it rests mainly on the idea that 

 no reptiles existed during the period that the lowest 

 fossiliferous strata were accumulating, then I say you 

 may yourself live to re- write that part of your story, 

 [n the progress of discovery, the whole series of geologic 

 speculations may change. From the very nature of the 

 investigations, an element of uncertainty must for a 

 long time mingle in all your most valued performances. 

 That stern, startling fact of ferns in the Orkney schists 

 must in no small degree tend to unsettle all fixed belief 

 in the findings of the stone, philosophers, if, indeed, any 

 belief can really belong to them." 



At Miller's request, Dick again went out to do his 

 biddings. " Eeferring you," he said (24th December, 

 1849), to a promise I made to you when down at Thurso, 

 to examine the groovings and polishings, by removing a 

 little of the soil in the locality in which you detected 

 those marks, I wish to remark that the work is done. 

 You might think me dilatory and slothful, but I could 

 not accomplish it sooner. In the first place, the business 

 was retarded by a severe frost. Winter held his iron 

 rule ; and could you have seen the place over which you 

 rambled in July last, you would have beheld a strange 

 metamorphosis. The strata were wholly covered witi 



