prestwich’ s geological works. 
117 
In discussing the question of climate, arising from the discovery of 
such an assemblage of post-tertiary fossils, Mr. Prestwich quotes a fact 
which may not he familiar to those of our readers who are not geolo¬ 
gists :— 
“ A remarkable confirmation of this view has since been afforded by the researches of 
a Russian naturalist, Dr. Brandt, who also observes, speaking of the Mammoth and the 
Rhinoceros (another animal that might seem to indicate a tropical climate), the remains 
of which are found associated in the drift of Siberia, that ‘ the thick covering of hair on 
both animals shows that a tropical climate was not necessary for their existence.’ He 
then proceeds to state that he has been so fortunate as to extract from the cavities of the 
molar tooth of the Rhinoceros, preserved in the frozen ground of Siberia, a small quantity 
of its half-chewed food, among which ‘ fragments of pine-leaves and minute portions of 
wood with a coniferous structure were still recognisable,’ showing therefore that the ani¬ 
mal could find food in the pine forests of those cold regions, and no doubt lived there.” 
The London Clay, which forms the subject'of the second and third 
Lectures, is better known than the London Drift; and we must, there¬ 
fore, refer our readers to the book itself for further information respect¬ 
ing it. 
The author has given a summary of his theoretical views in the last 
ten pages, commencing page 71. It is too long to quote, but possesses 
the highest interest, proceeding as it does from a geologist who has done 
more, by his personal exertions, to throw light on the English Tertiaries, 
than any other living geologist. 
Mr. Prestwich’lS other and earlier work is well known to every hy¬ 
draulic engineer, as a manual of the theory of wells and Artesian springs 
in the London Clay. We refer to it now, in order to render the author 
a justice which has been denied him by some who were more anxious 
to find a flaw than to render homage to the sagacious predictions of 
science. 
The work is, in brief, a detailed prediction of the probable results of 
sinking Artesian borings in London into the Lower Greensand beds below 
the chalk. Mr. Prestwich’s estimate is as follows, vide page 142 :— 
Feet. 
Tertiaries,.200 
Chalk,.650 
Upper Greensand, .... 40 
Gault,.150 
1040 
The experiment recommended by Mr. Prestwich has actually been 
tried by the Hampstead Water Works Company, who found the follow¬ 
ing thicknesses of the strata down to the top of the lower greensand:— 
Feet. 
Tertiaries, .... 
. . 324 
Chalk,. 
Upper Greensand, 
. . 72 
Gault,. 
1113 
