It does not appear that a glacial cap of any considerable extent was formed in Great Britain at this stage, but about this time the first great ice-cap was formed in British North America west of Hudson Bay, which sent its ice-sheets as far south as Iowa and Nebraska. In the latter State forests of spruce and other coniferous species indicate the appearance of a cool temperate flora in advance of the glaciation. In the Swiss Alps the snow descended 1,200 meters below the present snow-line, and in Scandinavia and northern Germany the first great ice-sheets were formed from which flowed the glaciers and rivers conveying the 'Old Diluvium,' or the 'oldest drift.' Accompanying the cold wave along the eastern coast of England we note, in the famous fossil deposits known as the 'Forest Bed of Cromer,' which overlie the Weybourn Crags, the arrival from the north of the fir-tree (_Abies_). This is most significant, because it had hitherto been known only in the arctic region of Grinnell Land, and this was its first appearance in central Europe. Another herald of northern conditions was the first occurrence of the musk-ox in England, which is attributed(7) to the 'Forest Bed' deposits. [Illustration: FIG. 25. The First (_Günz_) Glacial Stage was far less extensive than that in the above map, which shows Europe in the Second Glacial Stage, during the greatest extension of the ice-fields and glaciers (dots), a period of continental depression in which the Mediterranean, Black, and Caspian Seas were connected. The line from Scandinavia to the Atlas Mountains corresponds with the section shown in Fig. 13, p. 37. Drawn by C. A. Reeds, after James Geikie and Penck.] While Great Britain was less affected at this time than other regions, there is no doubt as to the vast extent of the First Glacial Stage in British America, in Scandinavia, and in the Alps; in the latter region it has been termed 'the _Günz_ stage' by Penck and Brückner. The 'drift' deposits have a general thickness of 98-1/2 feet (30 m.), but they are largely covered and buried by those of the far more extensive Second Glacial Stage. The Scandinavian ice-sheet(8) not only occupied the basin of the Baltic but overflowed Scania--the southern part of Sweden--and extended as far south as Hamburg and Berlin. In the Alps the glaciers passed down all the great mountain valleys to the low grounds of the foreland, implying a depression of the snow-line to 4,000 feet below its present level. [Illustration: FIG. 26. The musk-ox, belonging to the tundra region of the arctic circle, which is reported to have migrated as far south as the southern coast of England during the First (_Günz_) Glacial Stage.] THE FIRST INTERGLACIAL STAGE. EOLITHS