230 GERMANY. 



of certain valleys, erratic blocks are found in large numbers. None have hitherto 

 been discovered to the north of the Algau Mountains, whilst in the valley of 

 the Inn they extend as far as Krayburg, a village lying some 25 miles from the 

 actual foot of the Alps. 



The pebbles, which in the plain sloping down towards the Danube are covered 

 with a thin layer of vegetable soil, gradually decrease in size as we travel away 

 from the mountains. Most of them are calcareous, and have evidently come from 

 the limestone Alps ; but mixed with them are found fragments of granite, gneiss, 

 and crystalline slate, undoubtedly derived from the more southern crystalline Alps, 

 which in the glacial epoch must thus have surpassed the limestone Alps in height. 

 Beyond the Danube the pebbles traceable to the Alps are mixed with débris 

 resulting from the disintegration of the Swabian Jura, and with quartz and other 

 flints brought thither by the torrents descending from the Bavarian Forest. In the 

 course of ages carbonate of lime has compacted some of these pebbles, but for the 

 most part they occur in loose accumulations. Engineers engaged in the con- 

 struction of railways found it impossible to drive tunnels through these masses of 

 shino-le and gravel. The cuttings which had to be substituted for the tunnels are 

 sometimes of astonishing dimensions : one of them is no less than 105 feet in 

 depth, whilst a railway embankment rises to a height of 170 feet. 



The beds of pebble decrease as we approach the Danube, loess, or loam, taking 

 their place. At the foot of the Alps only very thin layers of loess are met with in 

 a few localities. lu the plains bordering upon the Danube the loess has a depth of 

 several yards, and the bones of mammoths have frequently been found in it. To 

 the north of the river it covers the hill-slopes to a height of 200 and even 400 

 feet above the plain, and its great fertility makes the country extending from 

 Ratisbon to the confluence with the Isar the granary of Bavaria. This district is 

 known as the Dunkelhoden, or " dark bottom " — a corruption of the older Duugau- 

 boden ; that is, Danube valley bottom. 



Lakes, Bogs, a>'d Rivers. 



Owing to the irregular configuration of the valleys through which the waste of 

 the mountains found its way into the plain, the deposition proceeded at a very 

 irregular rate. The plateau of Bavaria, far from being a plain, has an undulating 

 surface. Ridges of hills usually extend along both banks of the rivers, whilst 

 the cavities beyond these ridges are occupied by lakes or swamps. The general 

 slope of the land facilitates drainage, and hundreds of small lakes have already 

 been drained, but there still remain a large number which for extent and depth 

 may fairly compare with any but the largest lakes of Switzerland. The Amraer 

 Lake, one of the largest amongst them, has low wooded shores. The AN^urmsee, or 

 Lake of Starnberg, is bounded by wooded hills of graceful outline, and its villages 

 are indebted to the vicinity of Munich for a large number of summer visitors. A 

 castle now occupies one of the islands, which in a former age was the site of a 

 lacustrine pile village. As to the Lake of Chiem, though larger than the others. 



