GEOLOGY OF BOTTOM OF SEAS—DE LAUNAY. So 
explorations undertaken with so much success during the past 
years in ocean depths show us similar strata in process of deposition 
and enable us in a measure to be present at the first stage—the sub- 
marine stage—of those sediments whose ancient equivalents have had 
likewise in their turn a history now terrestrial, now marine or lacus- 
trine again, so complicated, so changeable with vicissitudes so 
diverse and such changing fortunes. 
We must not forget, however, and on this point I must insist 
because it is fundamental, that what to-day is the land, was yester- 
day, and to-morrow may again be, the ocean. Our moving and 
changing earth, while carried on its unbridled course through space, 
is unceasingly developing and is transformed, just as are the living 
beings on its surface, whose changes we can see, by laws which though 
of another nature have none the less, in their origin, one and the same 
cause—the very general principle of tendency to equilibrium and to 
least resistance. The movements of the waters pass and repass over 
our continents like the tides on a beach. Twenty times in the short 
period which represents one of our geologic stages a locality like 
Paris has been covered by the floods or has emerged again. There is 
not a spot on our globe which has not, like that Atlantis whose his- 
tory last year M. Termier so eloquently recalled to us, been sub- 
merged by the ocean after having been inhabited for a time by ter- 
restrial beings. And to-morrow, perhaps, if geologic history con- 
tinues, as everything indicates it will, some new changes of the same 
order may be produced, for example, in the troubled zone of our 
Mediterranean Sea—the emergence here of lands and the reflux of 
the seas driven from their old bed coming to submerge the conti- 
nents. The features which seem to us the most essential of our pres- 
ent physical geography are only entirely momentary forms, pro- 
visional and ephemeral, destined to disappear in this perpetual move- 
ment of destruction and construction, in this incessant turmoil of 
forces and of matter which moves the universe in space as well 
as the atoms in a grain of sand. Geology teaches us also that the 
highest elevations of the globe, those which to men of antiquity 
seemed to constitute the oldest parts of the earth, the bodies of titans 
struck by lightning in their fight against the heavens, the Alps, the 
Caucasus, and the Himalayas, are quite recent wrinkles of our crust, 
the heights and escarpments of which remain only because time has 
so far failed to erode and destroy them. It shows us likewise in the 
deepest abysses of the sea some recently formed hollows. 
By reason of these incessant movements, while the bottom of 
the seas is the laboratory where future continents are made, it is 
also the vast tomb where are concealed and preserved, in such 
measure as the mummy of the past may be preserved, certain con- 
tinents that have disappeared. The geology of the marine sub- 
