Its size, like that of the modern elephant, must have varied considerably. The famous St. Petersburg skeleton measures but nine feet in height, while that in the Royal Museum of Natural History in Brussels reaches eleven feet, and the animal in the carving, judging from the relative size of the figures, would have been still larger than Beckendorff's carcass, which he declares measured thirteen feet in height. Geology tells us much of the aspect, epoch, habits, and range of the mammoth; that it had appeared later than the mastodon, and somewhere in the age known as the Pliocene; that there were several species--three at least--two of which were inhabitants of America; that in North America it ranged from Behring Strait to the Gulf of Mexico, and in Europe from the extremity of Eastern Siberia as far south as Rome and the Pyrenees; that it fed upon the branches of the fir, birch, poplar, willow, etc., and was probably migratory in its habits, wandering toward grazing grounds in the north in summer, and southward in winter. The long shaggy hair with which it was clothed, distinguishing it in appearance from the modern elephant and its smaller contemporary, the mastodon, was composed of three distinct suits: the longest, rough, black bristles, about eighteen inches in length; the next, a coat of finer close-set hair, fawn-colored, from nine to ten inches long; and the last, a soft, reddish wool, about five inches long, filling up the interstices between the other hair, and enabling the animal to withstand an arctic cold. The enormous tusks measured along the curve from eleven to fifteen feet, and curved quite abruptly outward and backward. The massive grinder, sometimes weighing seventeen pounds, was a conspicuous characteristic; the whole of its surface was not brought into use at once, but successively, new grinding-points being formed from behind as the outer and older points wore away. Several etymologies have been given for the name "mammoth"; among others, the word "behemoth" in the Book of Job, and the Arabic word "mehemot," signifying an elephant of very large size. One of the most interesting is the Tartar word "mamma," meaning the earth, suggested by Pallas, a Russian scientist, who first gave a description of the animal. "The Tungooses and Yakoots," he says, "believed that this animal worked its way in the earth like a mole. The mammoths had retired, they say, into great caverns from which they never emerge, but wander to and fro in the galleries; and as they pass into one the roof of the gallery rises, and the roof of the one just vacated sinks. The moment this animal sees the light it dies, and the reason why so many carcasses have been exposed to view is because of their having been deceived by the irregular conformation of the earth's surface, thus unintentionally venturing beyond the confines of darkness."[C]