compared with the New World. 261 
trunk of this miniature willow is scarcely thicker than an ordinary 
pipe. Certainly these woods and shells do not belong to the actual 
flora or fauna of these regions, as Captain MacClure himself remarks ; 
neither can they be regarded as proofs of a deluge, for they are 
greatly anterior to the dispersion of diluvial deposits. 
Nore 7. The greater part of fossil species, embedded in the polar 
regions as well as everywhere else, are allied rather to the species of 
tropical countries than to those of temperate ones. This circumstance 
proves that the temperature must have been more elevated and at 
the same time more uniform, at the time when these beings lived, 
than it is now. 
Nore 8. The calorific rays of the sun do not penetrate below 28 
or 30 metres of the solid beds. At this point the temperature is 
uniform, and nearly constant at all seasons. Ifthe earth did not 
receive any other heat than that which it derives from the Sun or 
other stars, this heat ought to diminish below the invariable bed. Now, 
instead of diminishing, it increases in proportion as we penetrate 
into the earth’s strata, which proves that the globe must have a tem- 
perature of its own. An objection, more specious than solid, has 
been opposed to this hypothesis. How can we judge of this increase, 
it is said, from a depth so inconsiderable as that of about 700 metres 
below which thermometers have been carried, and thence conclude 
that the temperature of the earth increases in a constant manner 
from the circumference to the centre? No doubt this depth is no- 
thing when we think of the earth’s radius ; but volcanic fires, ther- 
mal waters, and the increase of heat which is evident wherever we 
descend below the invariable bed of 28 or 30 metres, are sufficient 
to show that the supposition is far from being without support. 
Nore 9. The influence of the figure and form of the terrestrial 
globe i is as perceptible on the physical phenomena which take place 
at its surface, as on the migrations of its people, their laws, man- 
ners, and all the principal historical facts of which it has been the 
theatre. With regard to the primitive liquidity of the earth, proved 
by the form it has taken, it cannot be attributed to water; the exist- 
ing quantity is much too small to have ever produced such an effect. 
That quantity scarcely amounts to the fiftieth-thousand part of the 
solid portion. Now as a liquid, whatever be its temperature, cannot 
_ dissolve a quantity of solid matter superior to it in weight, it follows 
that the terrestrial waters could not dissolve the entire materials 
composing the whole globe. We must therefore have recourse to 
another cause. . Among those whose action has been manifested in. 
a great number of phenomena, only one can produce such an effect. 
That cause is heat, as indicated by the composition of the portion of 
the earth known to us. It also follows from this, that the principal 
part of our globe presents not the least trace of organic remains, 
and is composed of rocks which are produced only under the influ- 
ence of a high temperature. 
