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 1^st. 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— 2^dly. 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—

3^dly that the submergence implied by the shells which occur at a height above 1300 f^t. is according to Ramsay above 2000 f^t. because the same continuous, stratified drift reaches to more than 2000 f^t.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, 1^st. Continental ice or Greenlandic period, 2^dly chief submergence, 3^d. 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

A is gravel containing freshw^r. 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 M^r 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