DIASTROPHISM AND THE FORMATIVE PROCESSES 570 
molten state—a view I do not now entertain—it would no doubt 
have assumed a state in which the lateral pressures would have 
been strictly equal and the vertical pressures also equal at any 
given depth, though of course varying with depth. The isostatic 
conditions would doubtless then have been complete and perfect 
in this radical sense, if we neglect such modifications as might have 
arisen from convection and similar internal disturbing activities. 
There should then have been a closely concentric arrangement of 
material according to its specific gravity, a uniformly level surface, 
and a universal ocean of uniform depth, as logically pictured by our 
geologic forefathers. This beautiful picture, were it true, would seem 
at first thought greatly to simplify the dynamic and diastrophic 
problems of the earth body, but in fact it forces upon us at 
once a problem of grave difficulty, the problem of finding a really 
rational way in which an earth, starting with such a symmetrical 
organization, could have passed into an earth with such irregulari- 
ties of form and substance, and such differentiations of specific 
gravity as are actually presented by the existing earth. The depth 
to which the specific gravities of the continents and the sub-oceanic 
segments have recently been found to differ presents a new and 
formidable difficulty. The recent revival of the doctrine of isostasy, 
on the basis of geodetic data,’ appears to have been regarded in 
some quarters as lending fresh support to the inherited view of a 
liquid earth, but in reality the results reached greatly augment 
a difficulty which had never been met with full success: the mode 
by which a horizontal differentiation of specific gravity in the outer 
part of the earth body could take place on a large scale, together 
with the mode by which the continental swells and the oceanic 
sags could be initiated and maintained. These great inequalities 
can be sustained only by adequate powers of resistance to the lateral 
stresses that tend to equate them and must always have tended 
to equate them. How such differentiations could have been forced 
upon a globe once in a fluidal condition—from which these 
‘The ‘“‘Figure of the Earth and Isostasy from Measurements in the U.S. Coast 
and Geodetic Survey,’ Washington, D.C., 1909, and other papers of John F. Hayford; 
see also G. S. Burrard, ‘‘On the Origin of the Himalaya Mountains, a Consideration 
of the Geodetic Evidence,” Prof. Paper No. 12, Survey of India, Calcutta, 1912; also 
Geol. Mag. Dec. V, Vol. X, No. 9 (September, 1913), pp. 385-88. 
