260 
course, the fossils of the group immediately under the Lias.* 
All facts connected with the developement of the Carboni- 
ferous group are of deep interest. You are aware that in 
the north of England and in Scotland coal beds alternate 
with the Carboniferous limestone down to its very base. A few 
insects and, I think, a few freshwater shells have been found 
among such alternating beds, but that fact does not diminish the 
value of your papers. I should like much to know the details of 
the discovery of organic remains in Mineral veins. That Mineral 
veins cut through beds with organic remains is a notorious fact, 
e.g., the lead veins cutting through the chert beds of Denbighshire. 
But in 1830 I made a short excursion into Swaledale and I found 
that in one place the Galena of the lead veins penetrated and 
perfectly mineralized some of the large Producte which retained 
their natural form. I think I have somewhere in my Museum a 
pretty good Producta absolutely composed of Galena. I wonder 
whether your case resembles the one I allude to. The lead veins 
in Swaledale pass through the Carboniferous limestone and [I 
believe that the fossils were all petrified before the veins were 
injected. The conversion of the Productz into sulphate of lead 
I consider a case analagous to the pseudomorphic crystals of tin, 
which very often in Cornwall replace the crystals of granite. I 
write in much hurry as I am expecting the arrival of friends from 
London, and after they leave me I am, D.V., to start on a visit 
to my native hills in the edge of Westmoreland. Pray give my 
kind regards to Mr. Jenyns and +Mr. Winwood and any other 
friends at Bath ; nor must I forget Mr. Weston, though he has 
deserted this mother earth and gone flirting with the fickle moon.” 
* “7 ¢, The Rhetic,” Moore adds in a note. 
+ This alludes to a visit paid in my company, during his short stay 
in Bath, to the section near the Weston Station on the Midland line, 
when I had the honour and the great pleasure of conducting the enthu- 
silastic and grand old man to the Rhetic section, recently so well 
