316 The American Geologist. May, 1892 
their relations to the courses of the present streams, is an interest- 
ing study in river drainage. The valleys of the ‘‘old” streams 
have been filled to considerable depths with sand, emanating from 
the glacier formations. In some places, and for considerable 
stretches, these ‘‘old” valleys are now dry. In other places they 
are occupied by inconsiderable streams. It would be a matter of 
ereat interest to know whether the ‘‘old” valleys are pre-glacial, 
or whether they are interglacial in origin. We infer that their 
sand filling is regarded as last glacial (p. 128). If it could be 
shown that the excavation of the ‘‘old” valleys was interglacial, 
or that any considerable part of their excavation was interglacial, 
such demonstration would be a convincing proof of a long inter- 
glacial epoch. 
Loess. On the southern border of the north German lowland 
there is a narrow belt of country covered with loess, although the 
loess is not confined to that portion of Germany which is properly 
designated “‘lowland.” It reaches to the southward so far as to 
cover the lower portions of the southern upland. The loess is 
well developed in the northern part of Saxony and in the vicinity 
of Halle and Magdeburg. The topography of the loess-covered 
country is gently undulatory. A large number of the German 
geologists who have studied the loess appear to have adopted the 
eeolian hypothesis. Dr. Wahnschaffe, on the other hand, believes 
the loess to have been deposited by water, and by water which 
arose chiefly fromthe melting of the ice in the /ast glacial epoch. 
He conceives the water which deposited the loess to have accum- 
ulated in a number of more or less connected basins, lying be- 
tween the ice on the north, and the highlands beyond the ice on 
the south. The waters thus confined between ice and upland had 
an outlet, so it is believed, toward the northwest; but it is held 
that the movement of the water was so gentle that it was able to 
carry away only the finest clayey material, while the materials of 
silt-grade of coarseness were deposited in the area covered by the 
water, and constitute the loess. The northward drainage from 
the highlands on the south, and the southward drainage from the 
ice on the north, both contributed to the formation. The altitude 
of the loess is stated to be about 282 feet in Saxony, while it rises 
to the hight of 600 feet in the Harz mountains. 
The chief reasons quoted from its advocates in support of the 
xoOlian hypothesis, are the presence of fossils of land animals. 
