224 Prof. Silliman’s Address before the 
voleanoes and other vents, to reveal the deep secrets of the 
earth.””* 
From all these sources, we have derived a competent know- 
ledge of the structure of the crust of the earth—of that portion 
with which we are immediately concerned. Every extension of 
geographical research, especially as prosecuted in modern times, 
by the English, the Russians, the French, and the Americans, 
whether in overland or in. maritime expeditions—to the islands 
of the Indian, Southern, and Pacific oceans, or towards the op- 
posite poles—conspires to confirm the conclusion thata grand 
uniformity and simplicity of design characterize the geological 
structure of all countries, however remote. There is the same 
order in the arrangement of the rocks—there are the same asso- 
ciations of strata and of minerals—the same fossils marking sim- 
ilar geological epochs ; and therefore we infer that a uniform code 
of laws has been prescribed for the whole. 
Coal, with its characteristic fossil vegetables, is found in Mel- 
ville Island, far within the northern polar circle, and Captain Ross, 
in 78° of south latitude, has recently discovered a powerful vol- 
cano in great activity, amidst the eternal snows and glaciers of 
the southern pole, flashing vividly upon the frozen Antarctic sky; 
from a crater at the elevation of 12,500 feet—a truly polar Ten- 
ériffe.t . ‘ 
Thus it appears that the polar lands of both hemispheres ate 
glowing with intense igneous action. Iceland is a vast classical 
region of volcanic fire; the antipodal polar zones are sustained, It 
may be, upon subterranean seas of melted rock, covered by moul- 
tains and glaciers of eternal ice and snow, through which the 
internal fires force, here and there, an opening, and thus reveal 
the secrets of the nether abyss. | 
OF ITS PROGRESS AND PRESENT CONDITION, ESPECIALLY IN THE UNE 
a TED STATES. 
. Within our present limits of time, it would be in vain that 
we attempt even a sketch of a general history of our science, 
and the effort would be quite superfluous, as the work has been 
admirab to our hands, in the introduction to Mr. Lyell’s 
eology. I trust I shall therefore be excused for 
gh, and Dublin Philos, Mag. for Feb. 1842. 
