Lignites of the same age as those of Dürnten and Utznach occur in many places both on the north and south sides of the Alpine chain. At Imberg, near Sonthofen, in Bavaria, for example, they are described by Penck[BJ] as being underlaid and overlaid by thick glacial accumulations. The deposits in question form a terrace along the flanks of the hills, at a height of 700 feet above the Iller. The flora of the lignite has not yet been fully studied, but it is composed chiefly of conifers, which must have grown near where their remains now occur--that is at 3000 feet, or thereabout, above the sea. It is incredible that coniferous forests could have flourished at that elevation during a glacial epoch. A lowering of the mean annual temperature by 3° C. only would render the growth of trees at that height almost impossible, and certainly would be insufficient to cause the glaciers of Algau to descend to the foot of the mountains, as we know they did--a distance of at least twenty-four miles. The Imberg lignites, therefore, are evidence of a climate not less temperate than the present. More than this, there is clear proof that the interglacial stage was long continued, for during that epoch the Iller had time to effect very considerable erosion. The succession of changes shown by the sections near Sonthofen are as follows. 1. The Iller Valley is filled with glacier-ice which flows out upon the low-grounds at the base of the Alps. 2. The glacier retreats, and great sheets of shingle and gravel are spread over the valley. 3. Coniferous forests now grow over the surface of the gravels; and as the lignite formed of their remains attains a thickness of ten feet in all, it obviously points to the lapse of some considerable time. 4. Eventually the forests decay, and their débris is buried under new accumulations of shingle and gravel. 5. The Iller cuts its way down through all the deposits to depths of 680 to 720 feet. 6. A glacier again descends and fills the valley, but does not flow so far as that of the earlier glacial stage. [BJ] _Die Vergletscherung der deutschen Alpen_, 1882, p. 256.