710 Holsts Studies in Glacial Geology. 
moraines, sometimes mainly from the former, at other places mainly 
from the latter, with the addition of material from lateral moraines 
where such exist. Furthermore, the terminal moraines are often 
traversed by jékel-rivers and numerous springs which agitate and 
grind down the contents of the moraine. The merely local occur- 
rence of terminal moraines and the mixed character of its contents, 
give to it a subordinate importance compared with the ground- 
moraine and the inner-moraine. Of still less importance are the 
lateral moraines and the middle-moraines. Of the latter kind none 
were observed by Dr. Holst. Lateral moraines are met with along 
the sides of the ice-rivers and at the foot of the nunataks. In the 
moraines are found some rocks not derived from the neighboring 
mountains. For this and other reasons, it seems evident that the 
lateral moraines are not altogether made up of débris from the 
adjacent sides of the mountains, but have received contributions 
from inner-moraines, and, in some instances, also from the ground 
moraine. 
Dr. Holst calls particular attention to the fact that in Greenland 
the blue and the yellow clays are formed simultaneously by the 
action of the same inland-ice, the former near its bottom where 1t 
is protected from the oxidizing influence of the air, the latter nearer 
its surface; and he regards the bearing of this observation as an 
argument against the theory, according to which the lower blue 
clay and the upper yellow clay in Sweden, Denmark, and Germany, 
are supposed to owe their formation to two different glacial periods. 
E. The upper-drift deposits are invariably found in process of 
formation in the larger valleys in front of the ice-rivers, Or, 10 
‘other words, along the greater jékel-rivers. Here they form more 
or less level plains, through which the river cuts its channel. 
Equal deposits are also met with in tracts from which the ice has 
departed, and here too their occurrence is confined mainly to the 
larger valleys in which once terminated greater or smaller 1ce 
rivers with jékel rivers issuing from them. The moraines from 
which the upper drift derives its material are partially the inner, 
partially the ground moraine, which first combine to form 
‘An abundance of Diatoms flourishes in the waters between pang 
minal moraine and the inland-ice. In one place, at Sarkarigso®, 
vegetation displayed a brilliant yellow color. 
e 
