276 
ORIGIN OF LIFE IN AMERICA 
as wo find them upon the existing continents, and concludes 
that there cannot be yet other continents with their own 
burdens of sediment hidden beneath the ocean. That former 
continents of any antiquity or magnitude are not hidden 
beneath the waves, says Professor Joly, seems certain, 
unless the estimates of sediments are quite erroneous. 
Whether the estimates are correct is a question which must 
be left to authorities in physical chemistry; but it has been 
argued by Professor Carthaus * that the waters of the 
ocean, as well as those of continents, were originally rich in 
sodium chloride, and that fresh-water organisms only came 
into existence comparatively recently, that is to say in late 
Mesozoic times. When we consider the enormous area of 
North America that was under water in Cretaceous times for 
instance, less than an equivalent strip of land in the shape of a 
trans-Atlantic land bridge would be all that is required for our 
purpose. We need not call it a continent. 
As for the arguments in favour of the permanence of con¬ 
tinents and ocean basins raised by Sir Archibald Geikie and 
Dr. Wallace, they are based on the following facts and 
assumptions, viz., great ocean depths, absence of abysmal 
rocks on present land surfaces, and absence of older Mesozoic 
or Palaeozoic rocks (with one or two exceptions) on oceanic 
islands. It has been shown, however, by Professor Suess that 
great depressions on the surface of the earth’s crust are not 
necessarily old or permanent. Quite near the south-west 
coast of Asia Minor, and close to the mighty Ak Dagh (10,000 
feet high), a depth of over 10,000 feet has been recorded. This 
depth is all the more remarkable when we consider that fresh¬ 
water Pliocene beds of the mainland are continued across to 
the neighbouring island of Rhodes, thus showing that the 
latter was, until such a recent geological period as the Plio¬ 
cene, still joined to the continent. Altogether Professor 
Suessf inclines to the view that geological evidence does not 
prove, nor even point to a permanence of the great depths, 
at least in the oceans of the Atlantic type. The next point 
which has been raised in favour of the view of the permanence 
* Carthaus, E., “ Klimatische Verhaltnisse der Geologischen Yorzeit.’ 
t Suess, E., “ Are Great Ocean Depths Permanent?” pp. 182 — 186. 
