ANNIVERSARY ADDRESS OF THE PRESIDENT. lxiii 
I conceive that distinct provinces of the distribution of terrestrial 
life have existed since the earliest period at which that life is re- 
corded, and possibly much earlier; and I suppose, with Mr. Darwin, 
that the progress of modification of terrestrial forms is more rapid 
in areas of elevation than in areas of depression. I take it to be 
certain that Labyrinthodont Amphibia existed in the distributional 
province which included the dry land depressed during the Carboni- 
ferous epoch; and I conceive that, in some other distributional 
provinces of that day, which remained in the condition of stationary 
or of increasing dry land, the various types of the terrestrial Sawrop- 
sida and of the Migaemalia were gradually developing. 
The Permian epoch marks the commencement of a new move- 
ment of upheaval in our area, which attained its maximum in the 
Triassic epoch, when dry land existed in North America, Europe, 
Asia, and Africa, asit doesnow. Into this great new continental area 
the Mammals, Birds, and Reptiles developed during the Paleozoic 
epoch spread, and formed the great Triassic Arctogeeal province. 
But, at the end of the Triassic period, the movement of depression 
recommenced in our area, though it was doubtless balanced by ele- 
vation elsewhere; modification and development, checked in the one 
province, went on in that “‘elsewhere”; and the chief forms of Mam- 
mals, Birds, and Reptiles, as we know them, were evolved and peopled 
the Mesozoic continent. I conceive Australia to have become sepa- 
rated from the continent as early as the end of the Triassic epoch, or 
not much later. The Mesozoic continent must, I conceive, have 
lain to the east, about the shores of the North Pacific and Indian 
Oceans ; and I am inclined to believe that it continued along the 
eastern side of the Pacific area to what is now the province of Austro- 
Columbia, the characteristic Fauna of which is probably a remnant 
of the population" of the latter part of this period. 
Towards the latter part of the Mesozoic period the movement of 
upheaval around the shores of the Atlantic once more recommenced, 
and was very probably accompanied by a depression around those of 
the Pacific. The Vertebrate fauna elaborated in the Mesozoic con- 
tinent moved westward and took possession of the new lands, which 
eradually increased in extent up to, and in some directions after, 
the Miocene epoch. 
It is in favour of this hypothesis, I think, that it is consistent 
with the persistence of a general uniformity in the positions of the 
great masses of land and water. From the Devonian period, or 
earlier, to the present day, the four great oceans, Atlantic, Pacific, 
Arctic, and Antarctic, may have occupied their present positions, and 
only their coasts and channels of communication have undergone an 
incessant alteration. And, finally, the hypothesis I have put before 
you requires no supposition that the rate of change in organic life 
has been either greater or less in ancient times than it is now; 
nor any assumption, either physical or biological, which has not its 
justification in analogous phenomena of existing nature. 
I have now only to discharge the last duty of my office, which is 
