584 T. C. CHAMBERLIN 
The nearly universal presence of gaping crevices over the whole 
face of the continents, affecting all classes of rocks, is quite in har- 
mony with a general spreading movement and has not otherwise 
found an altogether satisfactory explanation. Supporting this 
also is the prevalence of tensional faulting to so great a degree 
that it has gained the name normal faulting." 
It can hardly be supposed that such lateral stresses as must 
exist within the continents from the nature of the case, can fail 
to produce some effect, since changes of various sorts are going 
on within the continents, particularly molecular changes stimulated 
by heat, pressure, and other forces, and these must be influenced 
by the lines of least resistance imposed by the differential stresses. 
The vital question is whether this is a matter of geologic consequence 
or not. We must apparently wait for a decisive answer, and in 
the meantime treat the possibility of effective creep hypothetically. 
The point of special interest in this discussion is the bearing 
which the hypothetical glacier-like creep of the continents has on 
such an adjustment of the land surface to the sea-surface as pro- 
motes systematic shelf-building and the development of shelf-seas 
as set forth in Article II of this series. We have found that ordi- 
nary diastrophic movements are, in the main, inimical to the close 
adjustments required. Continental creep is, however, regarded 
as essentially independent of ordinary orogenetic or epeirogenetic 
diastrophism; indeed it is regarded as, in a sense, their reversal. 
Its action is suspended or overwhelmed by movements in the oppo- 
site direction when a diastrophic revolution is in progress. It is 
only when ordinary diastrophism is quiescent and the continents are 
in their relatively static stages that the slow, gentle reactionary 
movement of creep is presumed to be appreciable. 
Now this is not so much a vertical movement as a horizontal 
one, though actuated by gravity. It is indeed downward in a 
degree but it is horizontal in its main expression. By reason of 
this, it is fitted to become a copartner with gradation in leveling 
the land and thus facilitating an advance of the sea. It is in itself 
a massive form of gradation; it works toward a base-level of its 
t For a discussion of creep in relation to faulting, see T. C. Chamberlin, ‘‘The 
Fault Problem,” Economic Geology, II, No. 8 (1907), 709-21. 
