CYRSTOSPHENES OR BURIED SHEETS OF ICE 



233 



shallow channels, the sides of which consist of the peaty and finer 

 alluvial material. Ponds or lakes are conspicuously absent. 



The surface of the whole country, whether composed of "muck," 

 gravel, or rock in place, is almost everywhere permanently frozen, 

 and while as yet comparatively few shafts have been sunk through 

 this frozen layer, the evidence at hand would seem to show that it 



Fig. I. — Ice formed by spring water in winter. 



has a thickness varying from forty or fifty feet on the higher, uncov- 

 ered parts of the hills, to two hundred feet in the moss-covered bot- 

 toms of the valleys. Here and there, however, there are unfrozen 

 channels in the otherwise frozen layer, through which springs issue 

 from the sides of the hills, carrying water from the deeper saturated, 

 and unfrozen ground through the frozen layer to the surface. 



Most of the known springs issue from the rock above the sur- 

 face of the alluvial deposits in the bottoms of the valleys, but some 

 have been exposed by mine workings beneath the ordinary surface 

 levels. They all discharge more or less water throughout the year. 



