347 
a portion of those living at the present time, are inhabitants 
of the Mediterranean, and are not found in the deposits, 
clearly showing a gradual increase of temperature. 
Having previously stated my objections to the diluvial 
theory, I must now express my dissent from some of the views 
broached by M. Agassiz, for it appears to me that he has 
carried his theory to an unwarrantable extent, when he infers 
that great sheets of ice resembling those now existing in 
Greenland, once covered all the countries in which unstrati- 
fied gravel now occurs.* 
Supposing the existence of a glacial state even to a limited 
extent, it is evident that very different conditions are neces- 
sary to those which now exist; one of the most powerful 
would be a different distribution of land and water ; and I do 
not consider that in the observations which have come under 
my notice, sufficient attention has been paid to the unques- 
tionable fact, that a great elevation of land has taken place 
since the commencement of the tertiary era. That there has 
been a very considerable rise in the surface of land within a 
comparatively very recent period, is evident from many facts 
which have been made known without any reference to the 
present inquiry. Perhaps no geologist has devoted so much 
attention to this subject as Mr. Lyell, and as his works are 
in the hands of every one who has paid the slightes^^ atten- 
tion to the science, I will only refer to a few striking 
instances. Thus we learn, " That beds of shells have been 
found at Preston, in Lancashire, 350 feet above sea, and on 
a mountain called Moel Tryfane, in Wales, near the Menai 
Straits, at 1,400 feet above that level, which contain species 
indisputably the same as those which now people the British 
seas ; and although on more accurate examination some slight 
intermixture of the extinct testacea will appear, yet the geo- 
* See Report of the Glasgow Meeting of British Association in the Athe- 
nseura, No. 682. 
