EARTH MOVEMENTS. 
ADDRESS OF RETIRING PRESIDENT, C. R. VAN HISE. 
The part of the world of which we have definite knowledge 
•consists, as stated by Powell, 1 of three moving envelopes, an 
atmosphere, a hydrosphere, and a lithosphere. That the air 
moves we are aware; that the waters of river and lake and 
ocean move we well know; but that the rock constituting the 
outer part of the supposed solid earth as certainly and as con¬ 
tinuously moves as do these envelopes of air and water, we may 
not understand. It is true that the majority of the greater 
earth movements are so slow that they ordinarily escape our ob¬ 
servation; yet their cumulative effects are of the same order of 
importance as the movements of air and water. The atmos¬ 
phere may be called the second hand of the world clock, the 
hydrosphere the minute hand, and the lithosphere the month or 
year hand. 
Kinds of Earth Movements. — With volcanic phenomena we are 
more or less familiar. The majority of the important active 
volcanoes are located along or near the continental borders, but 
this statement is not applicable in the case of the several great 
past periods of igneous activity. 
As a consequence of volcanic action material within the earth 
is brought to the surface. In historic times the material thus 
transferred has been considerable in amount, but in the past 
at different periods and in various regions volcanic products 
have buried great regions to the depth of hundreds or thousands 
of feet. Accompanying volcanic outbursts of material, great 
transfers of liquid rock from one place to another have occurred 
within the outer part of the earth, no evidence of which appears 
1 Physiographic features, by J. W. Powell: Nat. Geog. Mon., Vol. I, 
No. 1, 1895, pp. 1-23 
30 
