394 
SECOND REPORT- 1832 . 
physical examination of the northern portion under their domi¬ 
nion. The celebrated Humboldt has also been enabled by the 
enlightened patronage of the Russian Government to exercise in 
Central Asia those powerful and generalized habits of research 
which had previously so greatly extended our physical know¬ 
ledge of the American Andes ; and although the personal obser¬ 
vations of this distinguished traveller have been restricted to 
the countries lying north of the Altai, between the Ural chain 
on the west and Chinese Tartary on the east, yet he has been 
enabled to collect from various sources the most important in¬ 
formation concerning all the adjacent regions, and especially 
w r ith regard to the very interesting interval between the Altai 
and Himmaieh mountains, which he has ably condensed in his 
Fragmens de Geologie et Climatologie Asiatiques *. We have 
already cited the European portion of Erman’s journey from 
Moscow to the Lena; that which relates to Asia is equally im¬ 
portant. 
Abstracts will be found in Ferussac’s Bulletin , of an account 
of the Altai mountains, by Ledebour, and of the environs of Lake 
Baikal, by Dr. Hess; the volcanized districts of Kamschatka, 
and the vast accumulations of fossil bones of the Elephant along 
the Siberian coast, have also received further illustration. 
* The most important general results thus collected are :—1. The correction 
of the notions previously entertained concerning the orography of Central Asia, 
which instead of consisting, as was supposed, of a vast elevated platform, is 
shown to be traversed by distinct chains separated by valleys not more elevated 
above the sea than the vale of Geneva. 2. The circumstances of the great 
depression beneath the level of the sea ranging around the Caspian and Lake 
Aral are much more precisely stated than in any former authority: this tract 
includes a space exceeding 18,000 square leagues, its lowest depression, the 
surface of the Caspian, being 320 feet below the level of the Black Sea. Hum¬ 
boldt inclines to attribute this vast subsidence to the protrusion of the elevated 
masses forming the adjoining mountain chains of the Caucasus, the Hindoo- 
Kho, and Iran. 3. Humboldt’s researches have greatly extended our know¬ 
ledge of the volcanic tracts of our globe ; he has shown the whole country round 
the Caspian to be a vast district of this nature, a “ pays cratere ” exactly resem¬ 
bling in its general outlines the telescopic appearance of the moon : he has also 
pointed out another great seat of volcanic action, still more important in its ex¬ 
tent, and interesting in the geological infei*ences to which it leads; this is the 
chain of Thion Chon, south of the Altai and ranging about 42° lat. N. and be¬ 
tween 70° and 90° long, east of London. This vast ignigenous district extends 
over 2,500 geographical square leagues, and being generally remote from every 
sea, shows that marine contiguity, although a common, is by no means an indis¬ 
pensable concomitant of volcanic action. It is justly remarked, that in the cases 
where such a proximity does exist, we may sufficiently account for it on the prin¬ 
ciple that in the neighbourhood of marine basins there would probably be less 
resistance to the disruption of the crust of the globe, here attenuated by excava¬ 
tion, than in more inland localities; without having recourse to the supposed 
access of infiltrations from the sea to imaginary beds of potassium, &c., thus 
causing an explosion. 
