s, burned up by no tropical sun, perhaps
form a special luxury for grass-eating animals, and that _even the
bleakest stretches of land in the high north are fertile in
comparison with many regions where at least the camel can find
nourishment, for instance the east coast of the Red Sea_.

The nearer we come to the coast of the Polar Sea, the more common
are the remains of the mammoth, especially at places where there
have been great landslips at the river banks when the ice breaks up
in spring. Nowhere, however, are they found in such numbers as on
the New Siberian Islands. Here Hedenstroem in the space of a verst
saw ten tusks sticking out of the ground, and from a single sandbank
on the west side of Liachoff's Island the ivory collectors had, when
this traveller visited the spot, for eighty years made their best
tusk harvest. That new _finds_ may be made there year by year
depends on the bones and tusks being washed by the waves out of the
sandbeds on the shore, so that after an east wind which has lasted
some time they may be collected at low water on the banks then laid
dry. The tusks which are found on the coast of the Polar Sea are
said to be smaller than those that are found farther south, a
circumstance which possibly may be explained by supposing that,
while the mammoth wandered about on the plains of Siberia, animals
of different ages pastured in company, and that the younger of them,
as being more agile and perhaps more troubled by flies than the
older, went farther north than these.

Along with bones of the mammoth there are found on the New Siberian
Islands, in not inconsiderable numbers, portions of the skeletons of
other animal forms, little known, but naturally of immense
importance for ascertaining the vertebrate fauna which lived at the
same time with the mammoth on the plains of Siberia, and the New
Siberian group of islands is not less remarkable for the
"wood-hills," highly enigmatical as to their mode of formation,
which Hedenstroem found on the south coast of the northernmost
island. These hills are sixty-four metres high, and consist of thick
horizontal sandstone beds alternating with strata of fissile
bituminous tree stems, heaped on each other to the top of the hill.
In the lower part of the hill the tree stems lie horizontally, but
in the upper strata they stand upright, though perhaps not
rootfast.[232] The flora and fauna of the island group besides are
still completely unknown, and the f