34 Dr Davy on the Action of Lime 
Forbes (p. 403), that the white crag represents of itself the 
moyen tertiary formation,—the red crag, the superior ter- 
tiary formation,—the deposits of the glacial period, the qua- 
ternary formation (newer pliocene), while the fresh water 
marls, and elevated regions would constitute two post-tertiary 
epochs. 
We have thought it right to discuss some of the hypotheses 
advanced by this skilful English naturalist, because it ap- 
pears to us necessary to shew the inconveniences arising 
from an attempt to give an account of facts hitherto inexpli- 
cable in one science (botanical geography), by drawing from 
another science (geology) suppositions, made, as it appears, 
with the sole view to these explanations, and for which there 
is no sufficient authority. We are far from thinking that 
these ingenious conjectures may not pave the way to some 
interesting discoveries, and that even many of them may be 
well-founded; but it is necessary to repeat, that proofs drawn 
from geology must rest on more certain data than those which, 
in this instance, have been adduced. 
On the Action of Lime on Animal and Vegetable Substances. 
By Joun Davy, M.D., F.R.S. Lond. & Edin., Inspector- 
General of Army Hospitals. 
LesketH How, AMBLESIDE, Nov, 14, 1849. 
My DEAR Sir,—If you think the following observations on 
the action of lime on animal and vegetable substances likely 
to be useful at the present time, you will oblige me by in- 
serting them in the Philosophical Journal. They were first 
published in a collection of essays* ten years ago. Notwith- 
standing, judging from instructions recently given on the 
subject of interments, and from the remarks of more than 
one writer on agriculture, the results of them, with the prac- 
tical conclusions to which they lead, seem to be little known, 
if at all,—I am, dear Sir, yours very truly, 
J. DAVY. 
To Professor JAMESON, 
s * Researches Physiological and Anatomical, 2 vols. 8yo. London, 1839, 
