NATURAL HISTORY. 
excludes from us two-thirds of the rock structures, 
and of the remaining portion, a large part is con- 
cealed by superficial depesits of various debris, 
covered by a carpet of vegetation ; so that a full 
and correct outline, of the extent and junction of the 
different formations, can only be imperfectly, and 
with considerable difficulty, approximated to. 
itis to the careful examination of those parts of 
the globe where the strata are most dislocated and 
inclined—where the elevations are great and abrupt, 
and the rifts and chasms frequent and deep, that 
we owe the larger part of what knowledge we pos- 
sess, of its structure : these characteristics occur 
chiefly in countries where rocks of the primitive and 
transition classes approach the surface; and as it is 
also in rocks of these formations, that the greater 
part of the metalliferous Lodes occur, (which are 
ramified cracks or fissures, in which ores, and other 
substances are imbedded,) we are in such districts, 
further assisted by the shafts and adits of the miner, 
Notwithstanding the various natural obstacles how- 
ever, the unwearied spirit of research, that charac- 
terizes the present age, is rapidly advancing this 
most interesting, and important branch of natural 
science, to the philosophic precision, carried to such 
perfection in the animal, and vegetable departments. 
Nothmg accelerates this, more than the connected 
and enlarged views, with which every branch of 
science is now studied, and by which they are all 
made to throw mutual light on each other, like the 
ornaments in the personification of the Poet, 
