386 Proceedings of the 



animals, the analogous species of which now exist only in the tropi- 

 cal regions, are found still covered with the flesh in the diluvium of 

 the plains in the north of Siberia, at the mouth of the Lena, and on the 

 banks of the Velhoui, between 72 and 64 degrees of north latitude, 

 it was immediately supposed that a sudden refrigeration of the tem- 

 perature had, at some period, been operated in those countries ; but 

 this phenomenon appears now susceptible of being more easily ex- 

 plained by the cold which, as M. de Humboldt has ascertained 

 recently on the spot, exists in the earth, even in the midst of summer, 

 at a depth of five or six feet. When at noon, in the months of 

 July and August, the air had a temperature of from 25 to 30 degrees, 

 M. de Humboldt found, between 54 and 58 degrees of latitude, four 

 wells of small depth, which had not the slightest remains of ice on 

 their borders, but the temperature of which varied from 2 6' to 1 4' 

 above zero. M. Erman found, on the road from Tobolsk to Ja- 

 koutsk, in the latitude of 56, springs at a temperature of 0' 1" and 

 3 8' above zero, when the atmosphere was at 24 ; but beyond the 

 parallel of 62 in the steppes, and even in the parallel of 60 in places 

 not very elevated, the soil remains frozen at a depth of from twelve 

 to fifteen feet. At Bogoslowsk, in the middle of summer, M. de 

 Humboldt found, at a depth of six feet, in a turfy soil, but slightly 

 shaded by trees, a bed of congealed earth 9| feet thick, traversed by 

 small fillets of ice, and containing groups of crystal of solid water, 

 like a porphyritic rock. At Jakoutsk (latitude 62) the subter- 

 ranean ice is a general and perpetual phenomenon, notwithstanding 

 the high temperature of the atmosphere in July and August ; and it 

 may easily be conceived, that from this parallel to that of the mouth 

 of the Lena, 72 N. latitude, the thickness of this bed of congealed 

 earth must rapidly augment. 



These facts being established, it may also be remarked, that tro- 

 pical animals, tigers precisely similar to those of India, are still seen 

 in Siberia. Several tigers, of an enormous size, have been killed 

 near the celebrated silver mine of Schlangenberg. Other animals, 

 which we now consider as peculiar to the torrid zone, have, doubtless, 

 as well as the bamboos, the ferns, the palm trees, and the coral 

 lithophyton, existed in the north of the ancient continent. This was, 

 probably, under the influence of the internal heat of the earth, which 

 in the most northern regions communicated with the atmospheric air 

 through the crevices of the oxydized crust. As the atmosphere be- 

 came chilled by the interruption of this communication, when the 

 crevices were successively obstructed by interposed rocks, or other 

 solid matters, the distribution of climate gradually became almost 

 entirely dependent on the solar irradiation, and the animal and vege- 

 table tribes, whose organization required an equal temperature of a 

 more elevated degree, became gradually extinct. Some of the most 

 hardy among the animals doubtless retired towards the south, and 

 lived some time longer in regions nearer to the tropics ; others, such as 

 the lions of ancient Greece, the royal tiger ot Dzoungaria,the panthera 



