334 Correspondence—Mr. Mark Stirrup. 
absence of marine organisms, or any traces of them, over the country 
generally, in the “Upper Boulder-clay,” said to have been the 
product of this ‘‘post-submergence glaciation,’ when the ice must 
have passed over hundreds of square miles of former sea-bottom. 
These and similiar difficulties led to the consideration of the hypo- 
thesis that the shells, or masses of shelly clay, may have been 
transported inland from a former sea-bed by the ice, as in many 
instances which had been proved and were well known. The ice- 
blocked condition of the North Sea, during the Glacial period, had 
been demonstrated by Messrs Peach and Horne and the late Dr. 
Croll, in their admirable papers on the “shelly till”? of Caithness. 
This, combined with the pressure of ice from the adjacent moun- 
tainous region of Inverness and Ross-shires, forced the great ice- 
stream issuing from Loch Ness to turn eastwards, and to some extent 
upwards, along the base of the hills to the south of Inverness, in the 
direction of Forres and Elgin. The striz and the distribution of 
boulders over the district abundantly proved this; and it was also 
clear that the ice must have passed over part of the former sea-bed 
in its progress. Other evidences from that part of the country of 
the transport inland of materials from the sea-bottom (as fragments 
of chalk, the limestone near Elgin, etc.) were alluded to; and the 
author held that, on the whole, till clear proof be obtained, doubts 
were justified as to this shelly-clay at Clava being really in place. 
In the concluding part of his paper the author referred to the “red 
clay,” with a few fragments of shells, described by Mr. Jamieson, of 
Ellon, as occurring in hollows and patches along the north-east of 
Aberdeenshire up to about 300 feet.! For reasons similar and 
additional to those already stated, he thought this clay could not be 
accepted as a satisfactory proof of submergence. It could be 
accounted for by the agencies which Mr. Jamieson had indicated, 
without submergence; and indeed, its characteristics seemed to be, 
in several respects, opposed to that theory. 
COE S 4 © AN esa G@aene 
ns 
“THE TRUE HORIZON OF THE MAMMOTH.” 
Srr,—As Sir Henry Howorth asks me to explain some of the 
remarks that I ventured to make against the cogency of his foreign 
evidence in favour of the pre-Glacial age of the Mammoth, I may 
premise, contrary to Sir Henry’s assumption of my recent acquaint- 
ance with the subject under discussion, that I have long taken an 
interest in the many problems that surround the question of the 
Mammoth and its times, and think that I have read, not without 
interest and appreciation, most of Sir Henry’s writings on this 
matter, but I must say that the reading has not always brought me 
to the same conclusions as the author. 
I have no pre-conceived views to support and endeavour to bear 
an open mind on the subject, and most certainly I had no idea 
of indulging in the dogmatism with which I am charged, for in 
1 Quar. Jour. Geol. Soc. vol. xxxviil. 
