3oo PREHISTORIC E UR OPE. 



us that after the great glaciers had for a long time occupied all 

 the low grounds of Switzerland, and even deployed upon the 

 plains of France and of the Danube, they at length melted away, 

 leaving the ground covered with boulder-clay and with sheets 

 and heaps of shingle, gravel, and sand, and sprinkled with large 

 isolated erratics. The climate gradually became milder, and a 

 flora resembling that of to-day covered the Swiss lowlands. 

 Man was at that time probably an occupant of the country, as 

 is shown by the discovery in the lignite of several small-pointed 

 rods, which are believed by Eiitimeyer and others to have 

 formed part of some basket- or wattle -work. How long this 

 mild interglacial epoch lasted we cannot tell. But its protracted 

 duration may be inferred from the thickness attained by the 

 brown coal. This, according to Heer, would require some 

 6000 years for its formation. Whether this estimate be over or 

 under the truth, it serves to show that the lignite could not have 

 accumulated between one of the comparatively rapid retreats 

 and advances which characterise the present Swiss glaciers. 

 The overlying morainic matter proves that the Linth glacier 

 again advanced — and that to a considerable distance — for 

 its terminal moraines are found at the lower end of Lake 

 Zurich. It ploughed down through the interglacial and older 

 glacials beds, sweeping them out of the bottoms of the valleys, 

 and leaving only shreds and patches of them fringing the hill- 

 slopes. This is very well exhibited at Utznach, where, standing 

 at the coal-mines which are driven into the hill-slope, we look 

 down into the valley at the head of Lake Zurich and see the 

 terminal moraines left during the retreat of the Linth glacier, 

 forming heaps and ridges. The lignites and freshwater sands and 

 clays evidently mark a former much higher level of the lake, 

 which must at one time have extended across the valley to a 

 similar elevation on the opposite side, where, indeed, patches of 

 the same old freshwater deposits have been detected. The latest 

 advance of the glaciers resulted, therefore, in the lowering of the 

 lake-level, and the demolition of the interglacial land-surface. 



1 For some further account of the occurrence of Pleistocene lignite in and 



