46 ACCOUNT OF FOSSIL TEETH AND BONES 
amid the rigours of a polar winter; and this difficulty cannot be 
solved by supposing them to have migrated periodically, like the 
musk ox and rein deer of Melville Island; for in the case of croco¬ 
diles and tortoises extensive emigration is almost impossible, and not 
less so to such an unwieldy animal as the hippopotamus when out of 
water. It is equally difficult to imagine that they could have passed 
their winters in lakes or rivers frozen up with ice; and though the 
elephant and rhinoceros, if clothed in wool, may have fed themselves 
on branches of trees and brushwood during the extreme severities of 
winter, still I see not how even these were to be obtained in the 
frozen regions of Siberia, which at present produce little more than 
moss and lichens, which during great part of the year are buried 
under impenetrable ice and snow; yet it is in these regions of ex¬ 
treme cold, on the utmost verge of the now habitable world, that the 
bones of elephants are said to be found occasionally crowded in heaps 
along the shores of the icy sea from Archangel to Behring’s Straits, 
forming whole islands composed of bones and mud at the mouth of 
the Lena, and encased in icebergs, from which they are melted out by 
the solar heat of their short summer, along the coast of Tungusia, in 
sufficient numbers to form an important article of commerce*. 
* “ Lieutenant Kotzebue has discovered, in the western part of the gulf to the north 
of Behring’s Straits, a mountain covered with verdure (moss and grass) composed in¬ 
teriorly of solid ice. On arriving at a place where the shore rises almost perpendicu¬ 
larly from the sea to the height of 100 feet, and continues afterwards to extend with a 
gradual inclination, they observed masses of the purest ice 100 feet high, preseived 
under the above vegetable carpet. The portion exposed to the sun was melting and 
sending much water into the sea. An undoubted proof of this ice being primitive (L e. 
not formed by any causes now in action), was afforded by the great number of bones and 
teeth of mammoths which make their appearance when it is melted. The soil of these 
