SLUDIES FOR STPUDEN RS 
AGENCIES WHICH TRANSPORT MATERIALS ON Diets 
AIS Ss) SUIRITACI I." 
CONTENTS. 
Wind. 
Water. 
Streams. 
Lakes and seas. 
Water and ice co-operating. 
Shore-ice and ice-floes with water. 
Icebergs with water. 
Ice. 
Glaciers. 
Glaciers and pan-ice co-operating. 
Significance of the abundance of stratified drift. 
When account is taken of all the foregoing considerations 
touching the character of the drift, the character of the rock 
surface which underlies it, and the relation of these to each 
other, we are able to exclude as principal agents of the drift, 
many of those forces which transport materials on the earth’s 
surface. The agencies prominently concerned in shifting loose 
materials are wind, water and ice. Other agencies of extreme 
violence, such as earthquakings and volcanic explosions, occa- 
sionally affect small areas. Suddenly and locally they accom- 
plish very considerable results in the way of shifting material 
from one point to another. The direct action of gravity, too, 
by producing landslides and by carrying loosened masses of rock 
down steep slopes effects much in the way of transfer of surface 
materials. But we have no warrant for believing that any or all 
these agencies can move such materials as those of the drift 
t The sequel to the articles which appeared under the heading Studzes for Students, 
Vol. II. Nos. 7 and 8. 
70 
