Along the upper Rhine the flint workers of Acheulean times established their ancient camps mostly in the open on the broad sheets of the 'lower loess,' which, constantly drifted by the wind, covered and preserved the stations. These stations are widely scattered, but they were frequented from earliest Acheulean times, and the region was revisited to the very close of the Upper Palæolithic. [Illustration: FIG. 77. Flint working stations of the Men of the Old Stone Age along the waters of the Ilm, the Rhine, and the Danube, from Acheulean to Azilian times. After R. R. Schmidt, modified and redrawn. These Palæolithic sites of Germany lie between the terminal moraines of the successive glacial advances of the Second, Third, and Fourth (II, III, IV) Glacial Stages, extending from the borders of the Scandinavian ice-fields on the north to those of the Alpine ice-fields on the south. The dotted surface represents the area covered by the drift of the Fourth Glacial Stage.] Early in Acheulean times the important 'loess' station of Achenheim was established. This is a most famous locality and is of especial importance because it is the only station in Germany which was continuously frequented from late Acheulean times throughout the Lower Palæolithic and into the beginning of the Upper Palæolithic; here the 'older loess' of the Third Interglacial Stage yields a typical Acheulean industry. Thus far the region of the middle Rhine and of Westphalia has not shown any evidence of Acheulean culture. The north German stations, however, were entered in Acheulean times, and the principal open stations of this region lie along the valley of the Ilm. Here, at Taubach, Ehringsdorf, and Weimar, we find implements of typical Acheulean form belonging to the early warm temperate Acheulean period. The stations of the Ilm valley southwest of Leipsic are also of great importance because of the rich record which they contain of the warm temperate animal life of early Acheulean times; the flint culture is typically Acheulean, and the climatic conditions are read both in the travertines and in the subsequent deposits of the 'lower loess,' which belong to the cold dry period of late Acheulean times. Here lingered the straight-tusked elephant and Merck's rhinoceros, contemporary with the workers of the Acheulean flints. It will be observed that in Germany the early Acheulean was a warm period which in certain regions was also arid and subject to great dust-storms. At this time the camps were for the most part in the open country. In the late period, also arid and subject to high winds but with a cooler climate, the flint workers continued to frequent the open Acheulean stations in the 'loess.' If there were shelter and cavern stations in this region, they have not as yet been discovered. This would appear to indicate that the climate had not yet become severe.