Edinburgh Geological Society. 557 
have come to be recognized and distinguished mainly by the records 
they contain of a rising and expanding Fauna. I know, gentlemen, 
all that has been said and written against the dangers of a priort 
reasoning in science, and beyond ail doubt it has often been misleading. 
But I know also that all the discoveries of science must take their 
place and rank in proportion as they fulfil and come up to the under- 
standings and expectations of the mind. For these understandings and 
expectations are part of our nature, and our nature is an epitome and 
an image of the vast system in which we live, so that we have a right 
to expect, in all physical research, that which we do actually find— 
namely, a more and more intimate correspondence between the facts of 
Creation and the intellect of Man. 
_ And this brings me to the successor of Hutton and of Playfair during 
the last fifty years—to Lyell, who has practically been the great law- 
giver in the philosophy of geology since the first publication of his 
** Principles.” In him the doctrine of mechanical repetition and of 
uniformity of sequence has found a prophet and an interpreter who has 
done as much as skill and knowledge can ever do to reconcile it with 
facts, and to give it a greater width of meaning. It is not too much 
to say that in this country, at least, although not on the Continent, 
Lyell’s authority has been supreme during the last thirty years; and 
no explanation of geological facts which was not supposed to coincide 
with his views has had a chance of favourable hearing. And yet, 
gentlemen, it is consistent with my personal knowledge that one, at 
least, of the most illustrious of our geologists—one of those who must 
ever be remembered as amongst the greatest teachers and greatest dis- 
coverers in the science—our countryman Sir R. Murchison, never did 
accept the doctrines of Lyell as an adequate or consistent explanation 
of numberless facts respecting the succession and the condition of rocks. 
Over and over again he has expressed to me his conviction that these 
facts could not be all accounted for on what he called the ‘“‘ bit-by-bit 
theory.”’ Now, as a matter of authority, | must express my own strong 
impression that the mind of Murchison had a more instinctive touch with 
Nature than the mind of Lyell. He was less under the dominion of 
one idea. He had a more open vision, and a more rapid and intuitive 
spirit of interpretation. He had not the same lterary power, and he 
was less disposed to construct abstract theories, which are attractive 
from their apparent simphcity and completeness. I would not have 
it thought for a moment that I undervalue the immortal services 
which Lyell has rendered to geology. He has taught us, as no other 
man had ever done before him, to appreciate the power of existing 
operations as we see them working every day around us, when these 
are multiplied by periods of indefinite duration. This was a lesson 
which we had much need to learn, for in the attainment of, our own 
ends and aims we are apt to be impatient of delay, and, transferring 
these weaknesses of our own character to our explanations of Nature, 
we are apt to forget the infinite patience of her operations, and her 
majestic indifference to the limitations of space and time. I have 
a vivid recollection of the keenness and enthusiasm with which Lyell 
has often told me of some new discovery illustrating the vast antiquity 
of even the last and latest changes on the surface of the earth, or the 
