Chapter CLI: Letter 526: TO J.D. HOOKER. Down, September 28th 1861

It is, I believe, true that Glen Roy shelves (I remember your Indian letter) were formed by glacial lakes. I persuaded Mr. Jamieson, an excellent observer, to go and observe them; and this is his result. There are some great difficulties to be explained, but I presume this will ultimately be proved the truth...