302 
of connection, excepting that of superposition, with the sub- 
jacent rock, give them quite the appearance of extraneous 
bodies, projected by some unknown cause on the spots where 
they now repose. 
* There are two theories, on the principles of which the 
geologists of the present day profess to explain the actual 
state of the earth's surface; the advocates of one theory 
maintaining that the dry land was elevated from the bottom 
of the sea by the expansive force of heat acting from below; — 
while the votaries of the other assert that the land was 
formed where it actually exists, and was left dry by the 
gradual recession of the sea within its present limits, after 
having, for a long period, covered the highest mountains. 
Without venturing an opinion on the comparative merits of 
these theories, as applied to the surface of the globe in 
general, there are certain facts connected with the Natural 
History of this island, as well as of Bourbon, that appear to 
me less repugnant to the principles of the former, than to 
those of the latter; and for the explanation of which, I would 
not hesitate to give it the preference, if I were called on to 
choose between the two. x 
m Their deep narrow ravines, and high precipitous moun- 
tains; the vast accumulation of angular fragments of a 
description of rock that appears peculiarly prone to disinte- 
gration; the almost total want of vegetable soil on their 
surface, and of alluvium along their shores; the remains, 
already noticed, of a belt of organic exuviæ reposing On thé 
surface of the ground, though apparently similar to those 
which are found in other parts of the world, buried deep 
| Within the bowels of the earth : these, and their uninhabited 
state at the era of their discovery, are points which favour 
so far as they go, the supposition, that the islands in question 
are of comparatively recent origin. Now, partial and 
successive formations of land are conceivable on the prin 
ciples of the Huttonian theory. The elevation of the whole, 
indeed, of the present dry land, may be considered as the 
result of a partial exertion of that power, which, "o 
to that theory, is in constant activity in the central region 
