412 VOLCANIC AGENCY. 
number of points, and when the tendency to estab- 
lish these communications gave rise, in the line of 
the long crevices, to the cordilleras of the Andes 
and Himmaleh Mountains, the chains of less ele- 
vation, and the ridges whose undulations embellish 
the landscape of our plains. Our author then men- 
tions, as proofs of these protrusions, the sandstone 
formations which extend from the plains of the 
Magdalena and Meta, almost without interruption, 
over platforms having an elevation varying from 
8950 to 10,232 feet ; and the bones of antediluvian 
animals intermingled on the summit of the Uralian 
ehain of northern Asia with transported deposites, 
containing gold, diamonds, and platina. Another 
evidence of this subterranean action of elastic fluids, 
which heave up continents, domes, and mountain- 
chains, displace rocks and the organic remains which 
they contain, and produce eminences and depressions, 
is the great sinking of the ground which occurs in 
the west of Asia, of which the Caspian Sea and the 
Lake Aral form the lowest part (320 and 205 feet 
beneath the level of the ocean), but which extends 
far into the interior of the continent, stretching to 
Saratov and Orenburg on the Jaik, and probably to 
the south-east as far as the lower course of the Si- 
hon (Jaxartes) and the Amou (the Oxus of the 
ancients). This depression of a continental mass 
extending to more than 320 feet below the surface 
of the ocean, he continues, has not hitherto obtained 
the necessary consideration which its importance 
demands, because it was not sufficiently known. 
It appears to him to have an intimate connexion 
with the upheaving of the Caucasian Mountains, 
those of Hindoo-kho, and of the elevated plain of 
Persia, which borders the Caspian Sea and the Ma- 
