THE PRESIDENTIAL ADDRESS 3 
that he can underpin it and substitute a new foundation: and, 
after all is finished, survey his edifice, not only more secure, but 
more harmonious in proportions than before.’ 
Although infinitely richer than when Darwin wrote, the Geological 
Record still is, and must from its very nature remain, imperfect. 
Every major group of animal life but the vertebrates is represented 
in the Cambrian fauna, and the scant relics that have been recovered 
from earlier rocks give very little idea of what had gone before, and 
no evidence whatever as to the beginnings of life. 
But, from Cambrian time onward the chain of life is continuous and 
unbroken. ‘Type after type has arisen, flourished, and attained 
dominion. Some of them have met extinction in the heyday of their 
development ; others have slowly dwindled away ; others, again, 
have not finished their downhill journey, or are still advancing to 
their climax. 
Study of the succession of rocks and the organisms contained in 
them, in every case in which evidence is sufficiently abundant and 
particularly among the vertebrates and in the later stages of geological 
history, has now revealed that the great majority of species show 
close affinities with those which preceded and with those which 
followed them; that, indeed, they have been derived from their 
predecessors and gave origin to their successors. We may now 
fairly claim that paleontology has lifted the theory of evolution of 
organisms from the limbo of hypothesis into a fact completely 
demonstrated by the integral chain of life which links the animals 
and plants of to-day with the earliest of their forerunners of the 
most remote past. 
Further, the rocks themselves yield proof of the geographical 
changes undergone by the earth during its physical history ; and 
indicate with perfect clearness that these changes have been so 
closely attendant on variation in life, and the incoming of new 
‘species, that it is impossible to deny a relation of cause and effect. 
Indeed, when we realise the delicate adjustment of all life to the 
four elements of the ancients which environ it, air, water, earth 
and fire ; to their composition, interrelationships and circulation ; 
itis perhaps one of the most remarkable facts established by geology 
that, in spite of the physical changes which we know to have occurred, 
the chain of life has never snapped in all the hundreds of millions of 
years through which its history has been traced. 
The physical changes with which Lyell and his successors were 
most closely concerned were, firstly, the formation of stratified rocks 
on horizontal sea-floors, situated in what is now often the interior 
