The evidence of interglacial conditions within the Alpine lands continues to increase. These are represented by alluvial deposits of silt, sand, gravel, conglomerate, breccia, and lignites. Penck, Böhm, and Brückner find evidence of two interglacial epochs, and maintain that there have been three distinct and separate epochs of glaciation in the Alps. No mere temporary retreat and re-advance of the glaciers, according to them, will account for the various phenomena presented by the interglacial deposits and associated morainic accumulations. During interglacial times the glaciers disappeared from the lower valleys of the Alps--the climate was temperate, and probably the snow-fields and glaciers approximated in extent to those of the present day. All the evidence conspires to show that an interglacial epoch was of prolonged duration. Dr. Brückner has observed that the moraines of the last glacial epoch rest here and there upon löss, and he confirms Penck's observations in south Bavaria that this remarkable formation never overlies the morainic accumulations of the latest glacial epoch. According to Penck and Brückner, therefore, the löss is of interglacial age. There can be little doubt, however, that löss does not belong to any one particular horizon. Wahnschaffe[AL] and others have shown that throughout wide areas in north Germany it is the equivalent in age of the Upper Diluvium, while Schumacher[AM] points out that in the Rhine valley it occurs on two separate and distinct horizons. Professor Andreæ has likewise shown[AN] that there is an upper and lower löss in Alsace--each characterised by its own special fauna. [AL] _Abhandl. z. geol. Specialkarte v. Preussen_, etc., Bd. vii. Heft 1; _Zeitschr. d. Zeutsch. geol. Ges._, 1885, p. 904; 1886, p. 367. [AM] _Hygienische Topographie von Strassburg i. E._, 1885. [AN] _Abhandl. z. geol. Specialkarte a. Elsass-Lothringen_, Bd. iv. Heft 2.