From Charles Lyell 30 September 1861
30 Sept. | 1861
My dear Darwin
I am afraid you will not have by you a spare copy of your welsh glacier paper alluded to in Jamieson’s last—vol. 33 Edinb. Phil. Journ. 18421 if you have I shall be very glad of it— if not I will try & buy but can at any rate borrow it.
I gather from Trimmer2 & E: Forbes3 1st. that the marine drift of Moel Tryfane with its 12 recent shells is not Crag, not even Norwich crag, but more modern & of the glacial period— 2dly. that the rocks on which this elevated post pliocene, marine drift rests are polished & were glaciated before the marine shells strata were superimposed— whether this glaciation was by land-ice or icebergs &c is a question I cannot answer—
3dly that the submergence implied by the shells which occur at a height above 1300 ft. is according to Ramsay above 2000 ft. because the same continuous, stratified drift reaches to more than 2000 ft.4
Now I begin to have little doubt that the Glen Roy roads are later than the great submergence, if Scotland was ever submerged like Wales as very likely it was.
But how to make these three periods, 1st. Continental ice or Greenlandic period, 2dly chief submergence, 3d. Glen Roy or glacier-lake period coincide with the period of Elephas antiquus Rhinoceros leptorhinus & hippopotamus major as contrasted with the (later?) period of the mammoth, tichorhinus (or wooly) rhinoceros rein-deer & musk buffalo?5
I now believe that at Bedford both these groups of mammalia were after the marine boulder-clay of that middle-county district.6
[DIAG HERE] B oolite glaciated erratic R. Ossa above Bedford A oolite boulder drift B oolite
A is gravel containing freshwr. shells & both sets of quadrupeds in different parts of the valley, probably not contemporaneous, but both posterior to B the northern drift & containing the wreck of said drift which was therefore anterior to the valley B. B. whereas the gravel A was posterior to excavation of valley.
At the bottom of A are human flint implements of the Amiens type7 used by men who lived when the valley was not so deep by 30 feet as now where the Oose flows.
These men lived, perhaps with Hippopot. major—after the elevation of the sea-bottom of the boulder clay of Bedford.— Was this last coeval with the marine drift of Wales? If so what were the relations in time between your last Lanberris glaciers & the excavatn. of the valley at Bedford & the mammoth of that ilk.8
Falconer & Prestwich place El. antiquus as well as mammoth of the caves of S. Wales as post glacial.9
I hope you will not merely wish Jamieson & me joy of having to solve these problems but give us an hypothesis at least about some of them.10
You may use the sea for your fringes above the pass of Mackul now that we give you a marine submergence before the shelves.
To save my copying these queries for Mr Jamieson be so kind as to return this letter that I may forward it to Ellon—
In the Norfolk cliffs Elephas antiquus was anterior to the erratics & glacial till—so it was near Zurich in Switzerland anterior to the largest Alpine erratics. But it seems to me to have been at Bedford a post-glacial beast.
Some of our Scotch peat bogs are surrounded by till & yet they & subjacent marl contain like the Danish peat bogs no extinct mammalia— Why is this.— The Danish peat lies also in depressions in drift & unstratified moraine-like boulder clay—
Were these glacial formations so modern that the fauna which immediately succeeded, a rich one, contained no extinct mammalia?
believe me | my dear Darwin | ever sincerely yours | Cha Lyell
Asks for copy of CD’s paper ["Ancient glaciers of Caernarvonshire", Collected papers 1: 163–71]. Gathers that drift of Moel Tryfan is glacial.
Believes Glen Roy roads formed later than submergence of Scotland.
Asks CD’s opinion concerning relative chronology of various glacial deposits, particularly a flint tool find in the Ouse River near Bedford.
Please cite as
Darwin Correspondence Project, “Letter no. 3270,” accessed on 24 July 2016, http://www.darwinproject.ac.uk/DCP-LETT-3270