4 O. TORELL, GLACIAL PIIENOMENA OF N: AMERICA. 
a. Preglacial beds. 
b. Stratified glacial deposits. 
c. A ground-moraine. 
d. The ice with its terminal moraines. 
or 
a. MSeratched rocks. 
b. A ground-moraine. 
c. Ice and terminal moraines. 
The first named section is the most common one in the parts 
of Europe covered by Scandinavian erratics. 'The second is 
found generally in Scandinavia and in the United States. 
The retrograde movement of a NE during the period 
of melting is lömfberised: 
1 By the formation of upper or terminal moraines 
which : are more or less levelled by the local backward - 
forward movement during successive intervals of time. 
2. By stratified river-deposits lying upon the unstrati- 
fied yellow moraines, so that a section above the sections 
just deseribed will present: 
a. Preglacial beds. 
b. Stratified deposits. 
ce. Till or ground-moraine. 
de Tse moraines levelled down to great fields 
containing unstratified material. 
e. Stratified beds formed by glacial rivers with gra- 
dually ascending sources. 
'The characteristics of the deposits b are: that only in 
the vicinity of high mountains they contain rounded stones, 
while farther away they consist of deposits of sand and clay. 
The characteristics of the deposits c are: a blue colour, 
due to seclusion from the oxydizing action of the ar; 
compactness and hardness; rounded form of the boulders, 
which are polished and scratched, and also generally brought 
from remote places. 
The characteristics of the deposits d are: a yellow and 
reddish colour, occasioned by peroxidation of the iron; com- 
parative looseness of the mass; and greater angularity of the 
boulders, which are rarely scratcehed and usually belong to 
neighbouring localities. 
The Slsmsetötisties of the deposits e are: stratification; 
abundance of rounded and unscratched boulders; they gene- 
rally consist of beds of gravel and sand without clay. 
