TRANSACTIONS OF SECTION C. 775 
indeed it is logically, though, considering the tenets of the upholders of catastro- 
phism, as opposed to those of uniformitarianism, at the time of that address, there 
is no doubt that evolutionism was rather a modification of the uniformitarianism 
of the period than intermediate between it and catastrophism, which was then 
practically extinct, at any rate in Britain. One of my predecessors in this chair, 
speaking upon this subject, says that ‘the good old British ship ‘‘ Uniformity,” 
built by Hutton and refitted by Lyell, has won so many glorious victories in the 
past, and appears still to be in such excellent fiehting trim, that I see no reason 
why she should haul down her colours, either to ‘‘ Catastrophe ” or “Evolution.” ” 
It may be so; but I doubt the expediency of nailing those colours to the mast. 
That Lyell, in his great work, proved that the agents now in operation, working 
with the same activity as that which they exhibit at the present day, might pro- 
duce the phenomena exhibited by the stratified rocks seems to be generally 
admitted, but that is not the same thing as proving that they did so produce them. 
Such proof can only be acquired by that detailed examination of the strata which 
I have advocated in this address, and at the time that the last edition of the 
‘Principles’ appeared, our knowledge of the strata was far less complete than it 
has subsequently become. It appears to me that we should keep our eyes open to 
the possibility of many phenomena presented by rocks, even newer than the 
Archean rocks, having been produced under different conditions from those now 
prevalent. The depths and salinity of the oceans, the heights and extent of con- 
tinents, the conditions of volcanic action, and many other things may have been 
markedly different from what they are at present, and it is surely unphilosophical to 
assume conditions to have been generally similar to those of the present day on 
the slender data at our disposal. Lastly, uniformitarianism, in its strictest sense, 
is opposed to rhythmic recurrence of events. ‘Rhythm is the rule with nature; 
she abhors uniformity more than she does a vacuum,’ wrote Professor Tyndall, 
many years ago, and the remark is worth noting by geologists. Why have we no 
undoubted signs of glacial epochs amongst the strata from early Cambrian times to 
the Great Ice Period, except in Permo-Carboniferous times? Is there not an apparent 
if not a real absence of manifestation of volcanic activity over wide areas of the 
earth in Mesozoic times? Were not Devonian, Permo-Triassic, and Miocene times 
periods of mountain-building over exceptionally wide areas, whilst the intervening 
periods were rather marked by quiet depression and sedimentation? A study of 
the evidence available in connection with questions like these suggests rhythmic 
recurrence. Without any desire to advocate hasty departure from our present 
methods of research, I think it should be clearly recognised that evolution may 
have been an important factor in changing the conditions even of those times of 
which the geologist has more direct knowledge. In this, as in many other ques- 
tions, it is best to preserve an open mind ; indeed, I think that geologists will do well 
to rest satisfied without an explanation to many problems, amongst them the one 
just referred to; and that working hypotheses, though useful, are better retained in 
the manuscript notebooks of the workers than published in the ‘Transactions of 
learned societies, whence they filter out into popular works, to the great delight 
of a sceptical public should they happen to be overthrown. 
May I trespass upon your patience for one moment longer? As a teacher 
of geology, with many years’ experience in and out of a large university, I have 
come to the conclusion that geology is becoming more generally recognised as a 
valuable instrument of education. The memory, the reasoning faculties, and the 
powers of observation are alike quickened. The work in the open air, which is 
inseparable from a right understanding of the science, keeps the body in healthy 
condition, But over and above these benefits, the communing with Nature, often 
in her most impressive moods, and the insignificance of events in a man’s lifetime, 
as compared with the ceaseless changes through the long eons which have gone 
before, so influence man’s moral nature that they drive out his meaner thoughts 
and make him ‘live in charity with all men.’ 
