For more than 10,000 years of the retreat, or until 6000 B.C., the ice-sheet was still sufficiently large and powerful to maintain a border of Arctic anticyclonic conditions on its southern edge. During the retreat the mean annual temperature of southern Sweden increased from 17° F. to 35° F., equivalent to a change from North-east Greenland to South Greenland. The July temperature rose to about 43° F. On the North German Plain still lived the reindeer and the fauna and flora of the sub-Arctic tundras; the mean annual temperature rose to 45° F. by the close of the period. The land flora in Sweden was entirely xerophilous, indicating a slight rainfall. There is also geological evidence of a small annual rainfall on the south-west coast of Norway. This period covers the transition from Palæolithic to Neolithic culture. It seems probable that the continental character of the climate of the final stages of the retreat phase was slightly increased by astronomical causes, the obliquity of the ecliptic being probably nearly one degree greater about 7500 B.C. than it is now. In Germany and Sweden this would have the effect of lowering the winter temperature and raising the summer temperature by rather more than 1° F. While the land was still falling rapidly in the north of Scandinavia and the Gulf of Bothnia, the coasts of Germany and Denmark began to rise, and about 6000 B.C. again closed[5] the outlet of the Baltic, converting it into a large fresh-water lake, the _Ancylus_ lake. A similar lake was formed farther east in central Finland. At this time the south-west Baltic lands stood more than 100 feet higher than at present. The land was probably still largely under the influence of dry easterly winds, and the shutting out of the Atlantic accentuated the continental conditions, and this stage in the climatic history of Europe is known as the “Continental Phase.” The winter climate was severe; at first the summers were not especially warm (July temperature about 54° F. in southern Sweden). This is probably the period of formation of the Ragunda moraines, and of a readvance of the glaciers on the Norwegian side of the divide, when the snow-line lay 200-300 metres lower than at present; it was also the time of the Daun readvance in the Alps. But as the land sank in the north and rose in the south, the waters of the _Ancylus_ lake retreated farther and farther north, and the summers became hot and dusty, with a mean July temperature of about 60° F. Everywhere in the Baltic regions the older _Ancylus_ beds show a monotonous pine-wood, but in the upper _Ancylus_ these are followed closely by a number of plants and shrubs of southern type—black alder, curled birch, linden, etc. The temperature continued to rise, and oak, Norway maple, ash, and finally, in the southernmost parts of Sweden, the common maple appeared. The last-named plant has been found below the present level of the sea in Ystad Harbour.