My dear Sir

Not having been lately in town, I received, only three days ago, your letter of the 8^th addressed to the Athenæum.—² I am much obliged to you for taking the trouble to give me your more deliberate opinion on the Jura blocks.— it is a subject which has long interested me much. The argument in favour of glaciers, versus icebergs, which I observe seems of the greatest weight with most people, has not much with me, namely the difference in the nature of the blocks in face of the different parts of the Alps: I have observed the same thing in Chiloe, on a small scale where there c^d be hardly any doubt that icebergs had been the transporting agents.— Each break in the Jura, would have had a tidal stream passing through it. & which would have affected a certain area of the inland sea-channel, subject of course to some disturbance from winds.— In the first Edition of my Journal, in the Appendix, I (rather foolishly) argued this point, going on Agassiz’s own facts;³ & I have not yet been convinced ⁠⟨⁠$\frac{1}{2}$ line missing⁠⟩⁠: the holes said to be made by cascades in the glaciers, has puzzled me most, but I have reason to suspect that eddies in the sea drill rocks in a very analogous manner.

Have you ever examined yourself the Jura? it would be a fine subject, & I feel sure, for one, whatever conclusion you came to, I sh^d be a convert.—

With thanks | Believe me | Yours very truly | ⁠⟨⁠signature excised⁠⟩⁠

There is a distinction (whi ⁠⟨⁠I⁠⟩⁠ pointed out in my paper on Boulders of S. Hemisphere) between true icebergs & coast-ice, which the more I think of it, appears to me to throw some light on some of the difficulties in this subject.⁴