My Dear Sir Charles,

I return you M^r. Darwin’s too flattering letter and am glad to find that he thinks his difficulties about Glen Roy sufficiently answered.¹

With regard to the lakes I think Ramsay’s idea is good altho he may push it too far.² It seems to me intelligible only on the supposition that whenever you have a glacially formed lake in a rock basin there must have been a spot of soft or more easily eroded rock otherwise how would the scooping commence.— D^r. Hooker says that glaciers sometimes raise their beds by accumulating debris underneath.³

Your explanation of the larger lakes not being filled up owing to the occupation of the hollow by the ice seems to me imperfect in as much as it does not account for the original formation of the hollow—.⁴

Your case of Zurich is very interesting.⁵

I think Ramsay should have shown that glaciers have the immense scooping power which he requires— as that is begging a good deal of the question.

I should like to know also how he explains the absence of lakes in the Himmalaya seeing how large the glaciers were there.

Your suggestion of a subsidence occurring in part of the course of a long valley ought I think to account for some lakes. and I think lines of fracture would account for others— Ramsay’s arguments against these latter seem to me not conclusive. for altho the original yawning chasm may have been removed by denudation yet the deepseated fractures would have a tendency to gape again during fresh movements of disturbance—⁶

However I am very much inclined to think that a great many lakes have been formed in the way Ramsay suggests— It is difficult otherwise to account for their immense number in those northern countries which have been so much ice worn.

I am glad to see that M^r Darwin thinks D^r Tyndall’s explanation of the glacial period insufficient—⁷ for I cannot see how it will answer for all that he supposes. Really will no astronomer come to the rescue and give us a lift with this great ice affair.⁸

I am | My Dear Sir Charles | Your very obed. serv | Tho^s. F. Jamieson.

P.S. I hope M^r. King will publish his lists of Clyde &c shells—giving those of each locality separate with the comparative prevalence of each species—⁹ I have often urged M^r. Smith of Jordanhill to make out accurate local lists but in vain.¹⁰

T. F. J.