Page:Quarterly Journal of the Geological Society of London, vol. 35.djvu/193

Rh allow of large masses of ice depositing their burdens over Britain north of the Lower Severn and the Thames, the animal would be pushed southwards into other districts where the climate was not so severe. In other words, it may be termed Glacial. When the conditions of life became less severe the animal found its way along the river-valleys of this country as far north as Yorkshire on the east, and the line of the Trent and Holyhead on the west. North of this line it is conspicuous by its absence from Postglacial deposits of sand and gravel. For this I should be inclined to account on the hypothesis that this area was defended from the invasion of the mammoths, and, it may be added, of the associated animals, by a system of glaciers radiating from the hills of Wales, Cumberland, the Pennine Chain, and Scotland, which did not melt away much before the mammoth became extinct, and possibly also by a submergence of the low districts.

In these remarks ossiferous caverns containing the remains of the mammoth have purposely been omitted, because it is impossible to tell with certainty their precise relation to the Glacial period.

The caverns and river-deposits of France present us with traces of the mammoth in enormous abundance, and the animal is known to have ranged into Spain, from the discovery of specimens in the zinc-mines of Santander. Thanks to M. Lartet and Dr. Falconer, it has long been known to have lived in the neighbourhood of Rome at a time when the volcanoes of Central Italy were active, and poured currents of lava and threw clouds of ashes over the site of the imperial city. It is abundant in northern and southern Germany, but it has not been found north of a line passing through Hamburg, or in any part of Scandinavia or Finland. It occurs in the auriferous gravels of the Urals; and in Siberia, as is well known, it formerly existed in countless herds, being buried in the morasses in large numbers, in the same manner as the Irish Elks at the bottom of the Irish peat-bogs. The admirable preservation of some of the carcasses is undoubtedly due to their having been entombed directly after death, and then quickly frozen up, a process which need not necessarily imply, as Mr. Howorth has lately suggested that it does imply, climatal conditions unlike those of the present time in Siberia. In unusually warm springs, the warm waters borne down by the great rivers from their southern warm sources thaw the frozen morasses with incredible rapidity, so that the hard ice-bound "tundra" becomes quickly converted into a treacherous bog. In