DIASTROPHISM AND THE FORMATIVE PROCESSES. IT 
SHELF-SEAS AND CERTAIN LIMITATIONS OF DIASTROPHISM 
T. C. CHAMBERLIN 
University of Chicago 
It will doubtless be agreed at once by all that the general con- 
figurations of the oceanic beds are due to deformative processes. 
There will be a readiness also to agree that the same is true of the 
beds of some of the seas and minor water bodies. On this back- 
ground of common opinion we may discuss sea-beds that do not owe 
their final form to diastrophism but to gradational processes. If 
all of the former class, large and small, be grouped as diastrophic 
basins, all of the latter class may be styled gradational basins, 
however incompletely the term basin represents their forms. 
There are of course composite and erratic forms that may be 
neglected here. The most familiar examples of the gradational 
type are the continental shelves. These are here regarded as only 
initial forms of the type, falling far short of serving as ideal repre- 
sentatives of the maturest class of sea-shelves. The waters that 
rest upon these sea-shelves may be known conveniently as shelf-seas. 
The ideal shelf-sea is not independent in origin; it is conditioned 
by the diastrophic sea from which it grows; diastrophism shapes 
the original basin; gradation superposes certain characters and 
extensons upon it. These new features are of radical importance 
in biological and stratigraphical development. 
Not only are shelf-seas conditioned at the outset by diastrophism 
but their histories hang on its continuous or its periodic action. If 
diastrophism is continuous, the gradational process constantly 
suffers disturbance and is ineffective; if diastrophism is periodic, 
gradation goes forward on given lines as long as quiescence con- 
tinues attaining greater and greater degrees of maturity of type, 
« This article is nearly identical in substance with a portion of a paper read at the 
Twelfth International Geological Convention, Toronto, Canada, August 16, 1913. 
523 
