St Andrews
6 Jany 1859
My dear Sir
I am glad my notes were of real use to you.1 I shall get the list of thicknesses finished as soon as the press of present work is over with me.
You will receive as soon as or immediately after this some section I made across Anglesey in one of which near the middle of the sheet there is a fault affecting the Carboniferous and Permian rocks somewhat of the kind you want. It is not however planed straight across. Nevertheless to a geological mind at all events it is equally good for the purpose. The scale is true vertically & horizontally. Some letterpress accompanies it in part of which there is a brief notice of the fault. I know another fault far more astounding in Merionethshire.2
It is thus
1 Llandeilo flags 2 Bedded felspathic trap, 3 Lingula flags. There is no mistake about the identity of the beds. The fault marked f is a down throw on the N.W. of about 12000 feet! I have been over the ground often. It is Selwyns work & I believe it. Selwyn was long with us & is now Director of the Geological Survey of Victoria3
Ever siny | Andw C Ramsay
There are scores of minor faults in the Oolites shaved quite flat across, many of them of several 100 feet. Ditto in the New Red Sandstone, and though unproved in the Miners sense of the term, they are equally satisfactory to you or I. The South Staffordshire coal field would scarcely be exposed at the surface but for faults
f faults. downthrows to E. & W. But for them the Coal Measures would probably still be under New Red. There has been a denudation on a kind of average level & hence they are exposed.
Ever Siny | Andw C Ramsay
Please cite as “DCP-LETT-2398,” in Ɛpsilon: The Charles Darwin Collection accessed on