MICHIGAN ACADEMY OF SCIENCE. 
131 
sinking sea bottom and the denuded and upfolding continent Shaler 
pointed to a fulcrum of no vertical movement, the position of a particu- 
lar bit of coast with reference to this line determining whether it stood 
still or shared in the marine depression on the one hand or in the 
continental elevation on the other. Since the position of the fulcrum 
need by no means be constant it is evident that this theory introduces 
a maximum of heterogeneity into the relations between the continental 
margin and the sea. 
While such action as was thus accepted by Shaler cannot be wholly 
excluded, and must fall into place as of possible local importance, it 
is not able to account for the major phenomena under discussion. The 
reasons for this are best stated bv Suess and Chamberlin and they are 
fj u 
freely quoted below. 
The confidence in land movements started out with the conspicuous 
Lvellian merit of being in harmonv with the facts of elevation and sub- 
sidence as actually observed and measured on various coasts. There 
seemed to be. no reason why, given time enough, the observed movements 
should not go on to values such as we have been engaged in compiling. 
Leading in the same direction too, was the conception of a rather rigid 
crust collapsing irregularly upon a cooling and shrinking spheroid. All 
went well on these lines as long as the vertical movements remained 
local and isolated so that when one region rose another might experi- 
ence a compensatory fall. Then came more extensive explorations and 
the knowledge that the vertical movements of greater degree are related 
over wide areas of the earth, and we find Professor Suess* remarking 
that “the theory of secular oscillations of the continents is not com- 
petent to explain the repeated inundation and emergence of the land. 
The changes are much too extensive and too uniform to have been caused 
by movements of the earth’s crust,” and again, “movements (like these) 
which present themselves as oscillations and extend around all coasts 
and under every latitude in complete independence of the structure of 
the continents, cannot possibly be explained by elevation or subsidence 
of the land. Even as the transgressions of the ancient periods are much 
too extensive and uniform to have been produced by movements of the 
lithosphere, so too are the displacements of the strand-line in the im- 
mediate past.” This clearly bears upon the question of correlation and 
its effect upon Shaler’s theory is evident. 
Reade.f in 1903, is still groping for the light for lie says: “None of 
the continents are now at their maximum height above sea level. Is it 
that the geographic forms of the spheroid are in less relief now than 
formerly, that the continental plateaux have subsided, or that the sea 
and ocean beds have risen? It is difficult to believe that the continental 
movements can have been coincident and universally in one direction all 
over the globe. It may be that in the vertical slow oscillations to which 
— the whole crust is subject, one land area has moved vertically up- 
wards while other areas subsided, and it happens that none of the con- 
tinents are now at their maximum elevation. The remarkable fact 
that the borders of all the continents, where sufficient soundings have 
been taken, show undoubted indications of having been formed by sub- 
aerial denudation, is a proof that at least portions of the land eonsti- 
*Suess, Eduard, "The Face of the Earth,” Eng. trans. vol. ii, Chap. xiv. 
fReade, T. Mellard, “The Evolution of Earth Structure,” 1903. 
