Edinburgh
Dec[ember]. 2nd /[18]49
My Dear Mr. Wallace,
I sent your letter to my colleague Dr. James Geikie1 and asked if he would be so good as to favour me with his opinion on the subject. This he has done in the enclosed letter. I observe, that like me, he does not place much weight in the fact that Palaeontologists have not recognised evidence of the existence of ancient glacial periods. I think the difficulties in the way of detecting far back [2] cold periods have not been fully recognized either by Geologists or by Palaeontologists as a rule. So strongly was I impressed with this when engaged on the subject in Climate and Time that I devoted a chapter to the details of those difficulties. Just consider how difficult, for example, will it be for the Geologist of the future to detect traces of our last glacial epoch a million of years hence. By that time all the [3] boulder clay will be denuded of the surface of the land and washed into the sea. The striaeted faciated surface of the rocks will be disintegrated and perhaps not a scratch left. Our raised beaches with Artic[sic] shell-beds, from which so much information has been obtained regarding the Arctic condition of our climate, will all be removed and the shells mixed up with those now living in our seas in such a manner that it will be difficult to say [4] whether the strata formed from our present sea bottoms will indicate a warm or a cold condition of climate. Now what will occur in reference to our recent glacial epoch, has actually occurred in reference to all the glacial periods of the past.
in reference to all the glacial periods of the past.
You need not return Dr. Geikie's letter. I have sent on my letter to Nature[.] I hope it may appear next week.
By the way an American Geologist, Prof. Orton[,] thinks that he has found evidence of coal-beds of inter-glacial age periods in the Carboniferous strata of Ohio in the Hawking[?] Rock District see Geol. Surv[ey]. of Ohio Vol. III 1848.
Yours truly | James Croll [signature]2
Status: Draft transcription [Letter (WCP2164.2054)]
For more information about the transcriptions and metadata, see https://wallaceletters.myspecies.info/content/epsilon
[1] [p. 340]
EDINBURGH,
2nd December 1879.
MY DEAR MR. WALLACE, — I sent your letter to my colleague, Dr. James Geikie,1 and asked if he would be so good as to favour me with his opinion on the subject. This he has done in the enclosed letter. I observe that, like me, he does not place much weight on the fact that palaeontologists have not recognised evidence of the existence of ancient Glacial periods. I think the difficulties in the way of detecting far back cold periods have not been fully realised either by geologists or by palaeontologists as a rule. So strongly was I impressed with this, when engaged on the subject in Climate and Time,2 that I devoted a chapter to the details of those difficulties. Just consider how difficult, for example, it will be for the geologist of the future to detect traces of our last Glacial epoch a million or years hence. By that time all the boulder clay will be denuded off the surface of the land and washed into the sea.[2] [p. 341] The glaciated surface of the rocks will be disintegrated, and perhaps not a scratch left. Our raised beaches with Arctic shell beds, from which so much information has been obtained regarding the Arctic condition of our climate, will all be removed, and the shells mixed up with those now lying in our seas in such a manner that it will be difficult to say whether the strata formed from our present sea-bottoms will indicate a warm or a cold condition of climate. Now what will occur in reference to our recent Glacial epoch, has actually occurred in reference to all the Glacial periods of the past.
You need not return Dr. Geikie's letter. I have sent on my letter to Nature.3 I hope it may appear next week.
By the way, an American geologist, Professor Orton,4 thinks that he has found evidence of coal beds of Inter-glacial periods in the Carboniferous strata of Ohio in the Hanking[sic] Rock district.5 See Geological Survey of Ohio,6 vol. iii. 1878.7 — Yours truly, | JAMES CROLL.
Status: Draft transcription [Published letter (WCP2164.6823)]
For more information about the transcriptions and metadata, see https://wallaceletters.myspecies.info/content/epsilon
Please cite as “WCP2164,” in Beccaloni, G. W. (ed.), Ɛpsilon: The Alfred Russel Wallace Collection accessed on 27 April 2024, https://epsilon.ac.uk/view/wallace/letters/WCP2164