Nordenskjöld[44] states that the savages with whom he came in contact frequently offered to him very fine mammoth tusks, and tools made of mammoth ivory. He computes that since the conquest of Siberia, useful tusks from more than twenty thousand animals have been collected. Mr. Boyd Dawkins,[45] in a very exhaustive memoir on this animal, quotes an interesting notice of its fossil ivory having been brought for sale to Khiva. He derives[46] this account from an Arabian traveller, Abou-el-Cassim, who lived in the middle of the tenth century. Figuier[47] says: "New Siberia and the Isle of Lachon are for the most part only an agglomeration of sand, of ice, and of elephants' teeth. At every tempest the sea casts ashore new quantities of mammoth's tusks, and the inhabitants of New Siberia carry on a profitable commerce in this fossil ivory. Every year during the summer innumerable fishermen's barks direct their course to this isle of bones, and during winter immense caravans take the same route, all the convoys drawn by dogs, returning charged with the tusks of the mammoth, weighing each from one hundred and fifty to two hundred pounds. The fossil ivory thus withdrawn from the frozen north is imported into China and Europe." In addition to its elimination by the thawing of the frozen grounds of the north, remains of the mammoth are procured from bogs, alluvial deposits, and from the destruction of submarine beds.[48] They are also found in cave deposits, associated with the remains of other mammals, and with flint implements. This creature appears to have been an object of the chase with Palæolithic man. Mr. Dawkins, reviewing all the discoveries, considers that its range, at various periods, extended over the whole of Northern Europe, and as far south as Spain; over Northern Asia, and North America down to the Isthmus of Darien. Dr. Falconer believes it to have had an elastic constitution, which enabled it to adapt itself to great change of climate. Murchison, De Verneuil, and Keyserling believed that this species, as well as the woolly rhinoceros, belonged to the Tertiary fauna of Northern Asia, though not appearing until the Quaternary period in Europe. Mr. Dawkins shows it to have been pre-glacial, glacial, and post-glacial in Britain and in Europe, and, from its relation to the intermediate species _Elephas armeniacus_, accepts it as the ancestor of the existing Indian elephant. Its disappearance was rapid, but not in the opinion of most geologists cataclysmic, as suggested by Mr. Howorth.