“Yesterday (and the previous days) I had some most interesting work in examining the marks left by extinct glaciers—² I assure you no extinct volcano could hardly leave more evident traces of its activity and vast powers. I found one with the lateral moraine quite perfect which D^r. Buckland did not see— Pray, if you have any communication with D^r. Buckland give him my warmest thanks for having guided me, through the published abstract of his Memoir,³ to scenes, and made me understand them, which have given me more delight, than I almost remember to have experienced since I first saw an extinct crater   The valley about here, and the Inn at which I now am writing must once have been covered by at least 800 or 1000 feet in thic⁠⟨⁠kness⁠⟩⁠ of solid Ice!— Eleven years ago, I spent a whole day in the valley,⁴ where yesterday every thing but the Ice of the Glacier was palpably clea⁠⟨⁠r⁠⟩⁠ to me, and I then saw nothing but plain water and bare roc⁠⟨⁠k.⁠⟩⁠

These glaciers have been grand agencies: I am the more pleased with what I have seen in N. Wales, as it convinces me, that my views, of the distribution of the boulders on the S. american plains, has been effected by floating Ice are correct.⁵

I am also, more convinced that the valleys of Glen Roy and the neighbouring parts of Scotland have been occupied by arms of the sea,⁶ and very likely (for on that point I cannot of course doubt Agassiz & Buckland) by glaciers also.”

C. Darwin