4. Interval between the _Bühl_ and _Gschnitz_ Postglacial advances in the Alps. A renewed steppe and 'loess' period. Climate cold and dry. Mammoth and woolly rhinoceros, reindeer, full tundra and steppe fauna very abundant. Crô-Magnon race in the stage of MIDDLE MAGDALENIAN culture. 3. The _Bühl_ stage of Postglacial advance in the Alps; renewal of severe conditions of cold moist climate, and spread all over western Europe of the arctic banded and Obi lemmings of the _Upper Rodent Layer_. _Bühl_ moraines in Lake Lucerne estimated as having been deposited between 16,000 and 24,000 years B. C. Crô-Magnon race dominant in the EARLY MAGDALENIAN stage of culture. 2. Period of the first Postglacial interval or _Achen_ retreat of the glaciers in the Alpine region. A dry cold climate. Crô-Magnon and Brünn races in the stage of SOLUTREAN culture. 1. Close of fourth glaciation, between 24,000 and 40,000 years B. C. Cold and moist but increasingly dry climate succeeding the fourth glaciation and deposition of _Lower Rodent Layer_, or first invasion of the arctic tundra rodents. Crô-Magnon and possibly Aurignacian race in the stage of AURIGNACIAN culture. BEGINNING OF THE UPPER PALÆOLITHIC THE AURIGNACIAN INDUSTRY We now glance at western Europe as it was between 25,000 and 30,000 years ago, at the opening of the Upper Palæolithic. During Aurignacian times France was still broadly connected with Great Britain.(11) The British Islands were not only united with each other but with the continent, while the elevation of the Scandinavian peninsula converted the Baltic Sea into a great fresh-water lake, the old shores of which are readily traced. Geikie also maintains that the rise of land in Scotland after the fourth glaciation was accompanied by an amelioration of climate and the advent of more genial conditions; a strong forest growth covered the lowlands, hence this is termed the _Lower Forestian_ stage of the physiographic history of northern Britain; it corresponds to the temporary period of the retreat of the glaciers in the Alpine region, which Penck has named the _Achenschwänkung_. The latter author is not inclined to connect any marked rise of temperature in the Alpine region with this interval of time; to our knowledge no fossil plant beds have been preserved which would give us such indications, and the animal life, as we shall see, certainly affords only a very slight indication of a rise in temperature in the retreat of certain of the snow-loving tundra and northern steppe lemmings to the north; the greater number of tundra forms remained. The continental elevation of the northern coast-line of Europe would explain the advent of a dry continental climate and the renewal of high prevailing winds, at least during the warmer and drier summer seasons, for it is certain that atmospheric conditions such as produced