288 Correspondence — Dr. James Geilde. 



lates below ice ; " and thirdly, that it may to some extent be true that 

 ice does override incoherent deposits without entirely obliterating 

 them. But he instances the section exposed in the North Suffolk 

 Cliff, where Till rests for a long distance upon a comparatively 

 undisturbed surface of sand, as proving that the former deposit has 

 been laid down in the sea, and as demonstrating the physical 

 impossibility of its having been accumulated under ice. Here, 

 again, Mr. Wood's argument is based as before upon the same 

 preconceived notion. He quietly ignores all the positive evidence 

 which has been adduced in proof of the subglacier origin and 

 accumulation of the chalky till of Suffolk, and brings forward not 

 one single jot or tittle of positive evidence in favour of his own view. 

 Yet, surely, if the Till in question were a marine formation, there 

 should be no lack of such evidence. If the chalky boulder-clay 

 were laid down upon the sea-bottom, a wide area in the south-east 

 of England must have been submerged, and that for a considerable 

 time. Where, then, I would ask, are the bedded gravel, sand, and 

 clay — the raised beaches and so forth — with marine organisms, 

 which we might reasonably expect to meet with ? Where, in short, 

 are the beds equivalent in origin to the shelly brick-clays, etc., of 

 Scotland, Scandinavia, and Canada? Can it be that the sea-bottom 

 of glacial times, in the East Anglian district, was dredged with clay 

 and peppered with stones and boulders at so rapid a rate as to 

 render marine life impossible ! 



I quite agree with Professor Young that the question of the 

 origin of Till necessarily precedes that of the preservation of inter- 

 glacial deposits, and I have before now expressed myself to that 

 effect. In the short paper which has called forth his remarks, the 

 subject of the origin of Till was not taken up for the simple reason 

 that I had already discussed that question at sufficient length else- 

 where. I still think that the theory of the subglacier origin and 

 accumulation of Till meets every difficulty, and offers a satisfactory 

 explanation of all the phenomena, and I can only regret that my 

 friend is of a different opinion. The view which he inclines to 

 favour has at the first blush a plausible appearance, but it will not 

 stand a closer examination. I was myself disposed at one time to 

 think that the Till might have been deposited in the sea in front of 

 an ice-sheet. But the explanation completely failed when I came to 

 put it to the proof. The objections to it are well-nigh legion, but 

 only one of these need be mentioned here — not because it is the most 

 cogent, but because it can be stated in very few words. Wide-spread 

 and thick deposits of Till occur on the lee-side of the Sidlaws, the 

 Ochils, and other hill-areas in Central Scotland, and many of the in- 

 cluded boulders prove that the Till in question has been forced up and 

 over these hills. Now, if the hills were submerged at the time they 

 received their coverings of Till, where, let me ask, was the ice-sheet ? 



Perth, April 20th, 1878. James GeikiE. 



Erratum. — From Mr. A. Champernowne, F.G.S. In Plate YI. Fig. 2 (of the May 

 Number), the arched dotted line over the group 3 is an error, and should be omitted. 



