Professor J. E. Marr — Address. 479 



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 fighting 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 produce 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 

 Archaean rocks, having been produced under different conditions from 

 those now prevalent. The depths and salinity of the oceans, the heights 

 and extent of continents, 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 re- 

 currence. Without any desire to advocate hasty departure from our present 

 methods of research, I think it should be clearly recognized 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 questions, 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 manu- 

 script 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 recognized 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 aeons which have gone before, 

 so influence man's moral nature, that they drive out his meaner thoughts 

 aud make him ''live in charity with all men." 



