Ice-beds on Eschscholtz Bay 109 



" Ice formations, in may respects similar to that at Elephant Point, 

 occur in various parts of the northern regions, both in America and 

 Siberia, wherever the frozen subsoil is found. This, according to 

 Baer, is coincident with the isotherm of 32° Eahr., and its thickness 

 increases in proportion as the mean temperature of the locality falls 

 below that degree, its unlimited descent being checked by the interior 

 heat of the earth. The extent and thickness of this frozen substra- 

 tum, whether increasing or decreasing, and to what extent affected 

 by local causes, are interesting subjects of inquiry. The thickness 

 of the frozen mass has been measured in various parts of the north 

 by boring. At Yakutz, Siberia, latitude about 62° and mean annual 

 temperature 14°, the ground was found frozen to a depth of 382 

 feet. At Fort Simpson, on the Makenzie River, in nearly the same 

 latitude as Yakutz, the mean annual temperature 25°, the frozen 

 substratum was found to terminate at 17 feet from the surface ; and 

 at the close of the summer of 1837 the surface was found to be 

 thawed to a depth of 11 feet, leaving only 6 feet of ground frozen. 

 So far there appears nothing remarkable in the frozen substratum, 

 it being controlled principally by the mean annual temperature of 

 the locality and the internal heat of the earth. But why this frozen 

 substratum should occur at certain places in the form of pure ice 

 does not appear so clear. Whether these ice masses are fragments 

 of the original ice sheet which overswept the polar regions, or are 

 formed by the waters from, the melting snow draining through the 

 soft, light mosses which form the tundra, is a matter for scientific 

 investigation. The presence of fossil remains of extinct species of 

 animals in some of the Siberian ice masses points to the supposition 

 that they have existed for many thousands of years, while some of 

 the ice examined by us near Elephant Point showed unmistakable 

 signs of having been formed by the melting snow filtering through 

 the surface covering. The mass, though many feet in thickness, was 

 composed of fine strata of ice, some pure and free from vegetable 

 matter, and some so filled with decayed moss as to present more 

 the appearance of frozen earth than ice. Upon being melted, how- 

 ever, it w^as found to contain but a small amount of vegetable matter, 

 which had a rank, disagreeable taste and smell. This peculiarity 

 was first attributed to the presence of animal matter, but, on ex- 

 amination with a microscope, revealed nothing but the remains of 

 the same species of plants which formed the covering of the whole. 

 A number of wedge-shaped pieces of ice found in the banks around 

 Eschscholtz Bay were probably formed by a small crack in the 

 ground filling with snow and ice, and continuing to enlarge under 

 successive changes from freezing to thawinar. 



