796 REPORT—1899. 
Lingulas, Trigonias, Port Jackson sharks, Ceratodus, Lepidosiren, and Protopterus, 
probably represent older faunas than anything to be found in the deep sea. 
Sir Wyville Thomson was of opinion that, from the Silurian period to the 
present day, there had been as now a continuous deep ocean with a bottom tem- 
perature oscillating about the freezing-point of fresh water, and that there had 
always been an abyssal fauna. I incline to the view that in Paleozoic times the 
ocean-basins were not so deep as they are now; that the ocean then had through- 
out a nearly uniform high temperature, and that life was either absent or represented 
only by bacteria and other low forms in great depths, as is now the case in the 
Black Sea, where life is practically absent beyond 100 fathoms, and where the 
deeper waters are saturated with sulphuretted hydrogen. This is not, however, 
the place to enter on speculations concerning the origin of the deep-sea fauna, 
nor to dwell on what has been called ‘ bipolarity’ in the distribution of marine 
organisms, 
Evolution of the Continental and Oceanic Areas. 
I have now pointed out what appear to me to be some of the more general 
results arrived at in recent years regarding the present condition of the floor of 
the ocean. I may now be permitted to indicate the possible bearing of these 
results on opinions as to the origin of some fundamental geographical phenomena ; 
for instance, on the evolution of the protruding continents and sunken ocean-basins. 
In dealing with such a problem much that is hypothetical must necessarily be 
introduced, but these speculations are based on ascertained scientific facts. 
The well-known American geologist, Dutton, says: ‘It has been much the 
habit of geologists to attempt to explain the progressive elevation of plateaus and 
mountain platforms, and also the folding of strata, by one and the same process. 
T hold the two processes to be distinct, and having no necessary relation to each 
other. There are plicated regions which are little or not at all elevated, and 
there are elevated regions which are not plicated.’ Speaking of great regional 
uplifts, he says further: ‘ What the real nature of the uplifting force may be is, 
to my mind, an entire mystery, but I think we may discern at least one of its 
attributes, and that is a gradual expansion or a diminution of density of the 
subterranean magmas. . . . We know of no cause which could either add to the 
mass or diminish the density, yet one of the two must surely have happened. .. . 
Hence I infer that the cause which elevates the land involves an expansion of the 
underlying magmas, and the cause which depresses it is a shrinkage of the 
magmas; the nature of the process is at present a complete mystery.’ I shall 
endeavour to show how the detailed study of marine deposits may help to solve 
the mystery here referred to by Dutton. 
The surface of the globe has not always been as we now see it. When, in the 
past, the surface had a temperature of about 400° F., what is now the water of 
the ocean must have existed as water vapour in the atmosphere, which would 
thereby—as well as because of the presence of other substances—be increased in 
density and volume. Life, as we know it, could not then exist. Again, science 
foresees a time when low temperatures, like those produced by Professor Dewar 
at the Royal Institution, will prevail over the face of the earth. The hydrosphere 
and atmosphere will then have disappeared within the rocky crust, or the waters 
of the ocean will have become solid rock, and over their surface will roll an ocean 
of liquid air about forty feet in depth. Life, as we know it, unless it undergoes 
suitable secular modifications, will be extinct. Somewhere between these two 
indefinite points of time in the evolution of our planet it is our privilege to live, to 
inrestignte, and to speculate concerning the antecedent and future conditions of 
things. 
When we regard our globe with the mind’s eye, it appears at the present time 
to be formed of concentric spheres, very like, and still very unlike, the successive 
coats of an onion. Within is situated the vast nucleus or centrosphere ; surrounding 
this is what may be called the tektosphere,! a shell of materials in a state bordering 
1 rnxrés, molten, 
