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hemisphere to another, the inhabitant of the 
north lands on some distant shore, he is sur- 
prised to find, amid a crowd of unknown pro- 
ductions, those strata of slate, micaceous schist, 
and trappean porphyry, that form the arid coasts 
of the Old Continent bathed by the icy ocean. 
Under every climate the rocky crust of the 
Globe presents the same appearance to the tra- 
veller ; he every where finds, and not without 
emotion, in the midst of a New World, the rocks 
of his native country. 
This analogy in unorganized nature extends 
even to those little phenomena, which we should 
be tempted to attribute to causes merely local. 
In the Cordilleras, as well as in the mountains 
of Europe, granite sometimes offers aggregations 
in the form of spheroids flattened and divided 
into concentric layers : under the tropics as 
well as in the temperate zone, we find in the 
granite some of those masses abounding in mica 
and hornblende, which resemble blackish balls 
enclosed in a mixture of feldspar and milky 
quartz ; schillerspar is found in the serpentines of 
the isle of Cuba, as well as in those of Germany ; 
the mandelstein and perlstein of the elevated 
plain of Mexico appear identic with those seen 
at the foot of the Carpathian mountains. The 
superposition of the secondary rocks follows the 
same laws in regions the most remote from each 
