MIGRATION OF NORTHERN MAMMALS. OM 
and lake Erie, and in modern geological times it ranged into the distant 
northwest as far as the Yukon river, where, last year, Mr William Ogilvie 
obtained two of its horns (which I have seen) in the gold-bearing gravel 
of Bonanza creek, in latitude 64°. The biche or red deer (Cervus cana- 
densis Erxleben) inhabited the St. Lawrence valley eastward to the outlet 
of lake Ontario in comparatively recent times, its remains in a good state 
of preservation having been found embedded in shell marl in at least 
two localities near Kingston. and also in the sand and gravel of Burling- 
ton Heights at a depth of 30 feet from the surface and at a height of 
77 feet above lake Ontario. Thirty years ago it was common in eastern 
Manitoba, but now it has retreated still further west. Such examples as 
the foregoing of annual and long-period migrations favor the supposition 
that the mammoth, in addition to its slower general movement of dis- 
persion to remote parts of the earth, made annual migrations in regions 
where such movements would be beneficial to him and might naturally 
be expected, as in northern Siberia. The average distance at the present 
day between the verze of the forest in northern Europe and Siberia and 
the coast of the Arctic sea is from 100 to 250 miles. 
Hven if the distance had been as great as this at the time when the 
mammoth inhabited these regions, which is not probable, this animal 
could easily move from the forest to the sea coast and back again between 
spring and autumn. But there is evidence that the modern forest-line 
has been retreating southward in both the old and new worlds. This 
tendency has prevailed for a great length of time, as is shown by the 
remains of trees of existing species on the coasts of Bering strait beyond 
the present limits of timber, and in Melville island off the northern coast 
of this continent, the latter occurring between 500 and 600 miles directly 
north of the nearest trees now growing on the Coppermine river and near 
Great Bear lake. The increased severity of the seasons in Greenland in 
historic times is another evidence of the deterioration of the subarctic 
climate, which appears to have this tendency all round the world, with 
perhaps a few local exceptions, as in one part of northwestern Alaska, 
due probably to a favorable change in the ocean current there. 
EXtTIncrion oF THE MAMMOTH IN SIBERIA 
The mammoth in northern Siberia probably passed the winters within 
the forest-line, where he would find shelter from the chilling winds and 
where he might live well, browsing on the small branchy spruce, larch, 
birch, etcetera. With the advent of spring he would begin his north- 
ward march, taking advantage of the long daylight, and he would spend 
LVI—Butt. Gero. Soc. Am., Von. 9, 1897 
