234 The American Geologist. -^i*"'- ^'^"^ 
tween the outer edge of the continental shelf and the inner 
boundary of the low lands. The marine sediments on the 
coastal plains prove them to have been covered by the sea. 
The eroded parts of the continental shelves could not have 
been developed at the present sea level. The "submerged 
dissected coasts in nearly all regions of the world indicate 
also a universal comparatively modern transgression of 
the ocean, for it seems highly improbable that nearly all 
the coasts could have been simultaneously depressed by 
tectonic movements." The coral reefs indicate a univer- 
sally late rise of sea level, while the elevated reefs indicate 
a pause in the vertical movements. The drowned valleys 
and fjords of the continental shelves and sub-ocean.ic 
continental slopes. * * * as of Niorway. Fosse 
Cap Breton, Congo, St. Lawrence, Hudson, etc., prove that 
there have ])een much greater oscillations of shore line; 
and this is confirmed by the suboceanic platforms and ter- 
races, as the lUake plateau, one southwest of Faeroes (at 
1200-1300 metres below the surface (p. 197). and deeper 
ones may be added by the reviewer. 
"What are the possible causes of these oscillations of 
the shore line? Are they due to movements of the litho- 
sphere or to possible oscillations of the hydrosphere or 
perhaps to both?" According to J. W. Spencer's interest- 
ing investigations of the drowned valleys of the Antillean 
region there have been a great many oscillations of the 
shore line during late geological periods. He believes that 
these oscillations have been due to epeirogenic movements, 
and assumes that in neighboring regions (it should be 
pretty distant one) "they have frequently not been simul- 
taneous." He further says that this does not harmonize 
with the remarkable uniformity of levels of the shelves, (p. 
198). "The greater part of the shelf must, according to 
Spencer's own description have been formed (as a coastal 
plain) prior to the formation or at least prior to the re- 
opening of the drowned valleys." Nansen thinks it "im- 
possible that the vertical oscillations of the shore line can 
have been due to more or less local tectonic movements, 
a fact which has hitherto hardly been sufficiently appre- 
ciated." The reviewer wishes here to state that at the 
