[Illustration: FIG. 186. Steppe mammals from the steppes and deserts of Asia, which invaded western Europe in Upper Palæolithic times; the first arrivals appearing during the cold, dry period of late Acheulean times, becoming more numerous in the dry period of Aurignacian and Solutrean times, and completely represented in Magdalenian times. The saiga antelope, the (_A_) steppe hamster, the (_B_) great jerboa, and the kiang, or Asiatic wild ass, are all shown one-twenty-fifth life size. The (_A_) steppe hamster is also shown one-fifth life size and the (_B_) great jerboa one-twelfth life size. Drawn by Erwin S. Christman.] [Illustration: FIG. 187. Ptarmigan, or grouse, carved in reindeer horn, from Mas d'Azil. After Piette. The restored portions (head and feet) are indicated by dotted lines.] The present flora of the subarctic steppes in southeastern Russia and southwestern Siberia includes forests of pine, larch, birch, oak, alder, and willow, extending along the banks of the rivers and streams and interspersed with broad, low, grassy plains. There are many gradations between the low and high steppes;(7) the climate in summer is relatively warm, the temperature rising to 70°, while the average temperature in mid-winter hardly exceeds 30°; in general there is a strong contrast between the summer and winter seasons, the steppe lands in summer are practically rainless, so that the sand and dust rise with every wind. Thus, both in summer and winter sand and dust storms play an important rôle. The great snow-storms of the subarctic steppes are as destructive as those of the more northerly tundras and often result in great loss of life. Numerous discoveries tend to prove that similar conditions prevailed in western Europe during Magdalenian times. Thus at Châteauneuf-sur-Charente, a mingled tundra and steppe fauna is found containing the bones of many young animals which must have perished during a blizzard. It will be recalled that in this region is the station of Le Placard of late Solutrean and Magdalenian age. Near Würzburg, Bavaria, there is a fauna buried in the 'loess' containing twenty species of mammals of the tundras and steppes, together with the bison and the urus.(8) Perhaps the strongest proof of the extension of cold, dry steppe conditions of climate is the migration of the saiga antelope (_Saiga tartarica_) into the Dordogne region, where it is represented both in carvings and engravings, and into other parts of southwestern France, where its fossil remains have been found in thirteen localities in association with a cold steppe fauna. In the same region have been found the remains of the musk-ox (_Ovibos_), one of the most distinctive members of the arctic fauna. HUMAN RACES OF MAGDALENIAN TIMES