230 ICE ITS FORMS AND FUNCTIONS. 



and preserving their imbedded organisms fresh and un- 

 changed for ages.* In all its aspects, ice is invested with 

 a curious interest ; in all its functions it is charged with 

 important results. To us, the inhabitants of an insular 

 and unstable climate, it may appear of little importance ; 

 but to those of the higher latitudes and altitudes it assumes 

 the boldest character, and achieves the most gigantic re- 

 sults. And these results, when accumulated for years and 

 ages, present to the geologist, as we shall see in the follow- 

 ing Sketch, phenomena as marvellous in magnitude, and as 

 complicated in character, as those produced by any other 

 agency to which the crust of our earth is subjected. 



like a signal-shot at sea ; large masses of rock are torn from their ancient 

 sites ; the ground in the tundras and in the rocky valleys cracks and forms 

 wide yawning fissures, from which the waters that were beneath the sur- 

 face rise, giving off a cloud of vapour, and become immediately changed 

 into ice." 



* It is chiefly in the frozen sands and gravels of the Siberian lowlands 

 that the remains of the mammoth and woolly rhinoceros are preserved 

 in greatest perfection. Every geological reader is acquainted with the 

 history of the St Petersburg specimen ; how hair, wool, and muscle were 

 so fresh, when first discovered, that even the dogs of the Tungusian 

 hunters were tempted to feed upon them, and this after the entombment 

 of ages ! The manner of their occurrence is thus described by the autho- 

 rity above quoted : " The banks of the rivers consist of sand-hills 150 or 

 200 feet high, and held together by the perpetual frosts which the sum- 

 mer is too short to dissolve. Most of these hills are frozen as hard as 

 rock ; nothing thaws but a thin outside layer, which, being gradually 

 undermined by the water, often causes large masses of frozen sand to 

 break off and fall into the stream. When this happens, mammoth re- 

 mains, in more or less good preservation, are usually discovered." 



