Correspondence—Mr. H. H. Howorth. 381 
CORRESPONDENCE. 
THE LOESS AND THE EPOCH OF THE MAMMOTH. 
Str,—Non omnia possumus omnes is an old adage especially to be 
remembered in complex inquiries. May I crave permission therefore, 
as I am honestly bound to do, to correct two errors of fact into which 
I have been led by the authorities I have followed. I followed Mr. 
James Geikie (Prehistoric Europe, p. 87) in naming the Lemming 
as found in Brixham Cavern. My friend Mr. Pengelly writes me 
that for Lemming ought to be writ Lagomys. ‘This substitution 
does not of course affect the argument I used, except by strengthen- 
ing it, since the Lagomys is more associated with grassy plains than 
the Lemming. Mr. Swanston in a courteous letter in the Gnon. 
Mae. for April corrects not so much me as Mr. Bell, whose paper 
I quoted. Here again, as he most fairly says, the correction does not. 
in any way affect the induction I made. It is at the same time 
singular that the highest points at which marine shells have occurred 
in the surface-drifts of Britain should be on opposite sides of St. 
George’s Channel nearly where it is narrowest, and where the water 
if rushing violently would be most throttled, and therefore rise to the 
greatest height. 
I would next crave a small space in which to refer to a theory 
propounded by Mr. Searles Wood, F.G.S., in a recent Number 
of the GronogicaL Magazine, and repeated by him in a recent. 
number of the Journal of the Geological Society, in which he claims 
to account for the Loess in a new way, namely, by lateral 
movements of the ground under conditions such as exist in the 
Siberian tundras. I confess that I have read over the passages in 
which this theory is maintained with surprise. Mr. Searles Wood 
is such an experienced field geologist that it would have been dan- 
gerous to suggest that he has never seen or handled Loess. He 
himself, however, makes this confession (Gro. Mac. Vol. LX. Second 
Series, p. 339). Only in this way can I explain the conclusion he has 
formulated. In the first place, he treats the Loess as being a mere 
form of loam, and identifies it with the Limon Hesbayen of the Belgian 
geologists. No doubt the two deposits are more or less synchronous, 
but without doubt they are very different in composition and texture, 
and require an entirely different explanation if we are to account for 
their origin. The first and most important feature of the Loess, 
which discriminates it at once from the loamy deposits and which 
requires a special explanation, is its being saturated with carbonate 
of lime. How does Mr. Wood’s theory meet this at all? The curious 
capillary structure of Loess is its second most remarkable; feature. 
This is assuredly entirely at issue with lateral molecular movements 
such as Mr. Searles Wood suggests. The long fine tubes that 
permeate the Loess so thickly would be destroyed and its structure 
rendered completely homogeneous by the slightest movements such 
as he supposes. Again, such movements could only occur if at all in 
a pasty plastic mass, but the structure of Loess is the antithesis of 
such a plastic condition. As Baron Richthofen says, ‘“ water which 
