260 Professors A. Helm and A. Penck — 



I. — The Division of the Quaternary Formation in the District of the 

 Highland Lakes of Bavaria. 



Throughout the lake district of Upper Bavaria, the basement bed 

 is everywhere formed by the " Flinz " (Upper Miocene Clay, Marl, 

 and Clayey Sandstone), on which rest the Quaternary beds, which 

 are briefly characterized below. 



(a.) A layer of Conglomerate (Nagelfluh) from 20 to 30 metres in 

 thickness, having a nearly even surface, and rising with remarkable 

 uniformity in a gentle slope towards the S. and S.W. It consists of 

 pebbles of limestone and dolomite, and contains very few erratics of 

 Archaean rocks. The material is fairly evenly rounded, and united 

 by a calcareous cement. Hollow boulders and decayed pebbles are 

 abundant in it. 



(&.) A deposit of gravel which may readily be distinguished from 

 the Conglomerate (a) or " Deckenschotter," by the greater irregu- 

 larity in the size of the pebbles, and the far greater abundance of 

 pebbles of Archaean rocks. It is seldom cemented into a conglomerate, 

 it contains no hollow boulders, but there are in it rolled fragments 

 of the diluvial Nagelfluh mentioned above (a). This gravel deposit 

 is the Lower " Glacialschotter " of Penck (Die Vergletscherung, etc., 

 p. 142). It is also of great uniformity and is widely distributed. 

 Its general dip from south towards the north is less than that of the 

 diluvial Nagelfluh (a), so that in the lake district to the south it is 

 deposited lower on the slopes of the valleys (which consist of 

 Miocene Flinz) than the Nagelfluh (near Weilheim 100 m.), whilst 

 towards the north, near Munich, it overlies the Nagelfluh. 



Here, in the Isar Valley above Grosshesselohe, an intermediate, 

 independent deposit of gravel (intermediate Schotter, Penck, Die 

 Vergletscherung, p. 290) is interposed between the Nagelfluh and 

 the Lower Glacialschotter, which has not yet been noticed in the lake 

 district. 



(c.) An irregular covering of genuine morainic material, swelling 

 up in places into hilly ridges, extends in the lake district, in a very 

 discordant manner, as well over the elevations occupied by the 

 Nagelfluh. as over the Miocene Flinz, and the slopes of the diluvial 

 gravels (b), up to the foot of the hills. Only in the district of the 

 outer moraines (near Furstenfeld-Bruck, etc.), are the diluvial 

 gravels (b) and the slopes of Flinz free from this morainic covering. 



The moraines show nearly the same admixture of pebbles as the 

 gravels (b). They contain scratched boulders, together with angular 

 fragments of the same kinds of rock. All these scratched and 

 angular fragments are usually small, they very seldom reach a 

 diameter of half a metre, generally they vary from the size of a nut 

 to that of one's fist. This type which is characteristic of the ground- 

 moraine is particularly represented also by the longitudinal ridges. 

 Therefore the latter may be recognized as the ground-moraine scooped 

 out at the margin of the ancient glacier. 



In the district embraced in our excursion, no moraines are present 

 at the base of the Nagelfluh or below the glacial gravels (b). 

 Below these latter, however, beyond the excursion district, near 



