MICHIGAN ACADEMY OF SCIENCE. 
27 
Compared with the theory of terrestrial loss of mass as I have de- 
veloped it, following Fisher and Pickering, Mr. Taylor’s theory pre- 
sents some resemblances and some contrasts. Both recognize certain 
coastal affinities between the opposite sides of the Atlantic oceans. Both 
explain these affinities on the basis of former continuity and fracture 
with separation. Under both, the Atlantic ocean is finis a widened 
crack, rent, or rift in the earth’s superficial materials. 
Then come the contrasts. Mr. Taylor’s motion is slow, that of the 
rival theory rapid. Mr. Taylor’s is mainly Tertiary in time, my de- 
velopment of the other theory makes the principal motion determine the 
division between Mesozoic and Tertiary time. Mr. Taylor’s theory goes 
a long way toward explaining the formation of the Atlantic and Arctic 
oceans, the other would explain the formation of all the oceans. Mr. 
Taylor’s theory harmonizes with current geological sentiment, its rival 
is a startling and doubtless an unwelcome, reversion to catastrophic 
violence. 
Mr. Taylor's theory has many elements of strength, resting as it does 
upon analysis of observed facts. Granting the Tertiary age of the moun- 
tain belts which border the Americas and, though less regularly, the 
mass of Eurasia, and granting, what seems clear, that these ranges 
have been produced by lateral movement due to pressure, we have ex- 
ceedingly strong grounds for belief in widespread crustal creep of the 
general nature claimed. Granting further, that the folding is toward 
the oceans, and that coastal affinities exist, as claimed, on the borders 
which are not folded, the conclusion seems reasonable that there was 
crustal creep in the continental sheets away from Greenland and toward 
the folded margins. The mountains were doubtless* slowly, probably 
intermittently formed, so the creep must have been timed accordingly 
and not all accomplished in one comparatively brief action. 
In the Tertiary mountain belt, two peculiar features are pointed out 
which strongly support Mr. Taylor’s conclusions, — two “mountain 
knots,” one in Alaska, the other in Peru, where convergences of crustal 
creep are advanced in explanation of excessive and tumultuous mountain 
building. These seem to be excellent evidence. Also, in addition to 
mountain ranges, he is able to point to numerous overthrusts, a few of 
considerable extent, the most notable example being one of a hundred 
kilometers in Scandinavia. 
While the theory rests upon Prof. Suess’ views of mountain structure, 
to which some may not give unqualified approval, still on the whole 
this is probably much more an element of strength than one of weakness. 
Lines of rifting and parting to the east and west of Greenland are 
indicated by the coastal contours, less upon the east side, Mr. Taylor’s 
illustration of those on the west of Greenland, his figures 4 and 5, being 
especially striking. 
I cannot admit that the coasts of Africa and South America fit into 
the outlines of the mid-Atlantic ridge, as he claims, but as I have pre- 
viously demonstrated, these two borders fit into each other in a most 
surprising manner if we can bring ourselves to disregard that ridge, 
and a line of parting is indicated which argues as strongly for Mr. 
Taylor’s theory as do the para-Greenland rifts. As f understand it, 
the mid-Atlantic ridge is not an essential part of his theory, he merely 
tries to accommodate it. 
