258 POPULAR SCIENCE MONTHLY. 



as to the nature of the material on which they would have to work; 

 but Dr. Prestwich had distinctly stated that the various formations 

 were considered " irrespective of their relative merits in any other 

 than a geological point of view." His plan had been to discuss 

 carefully all the strata underlying the Channel, from the London 

 clay down to the Palaeozoic series, and deduce his conclusions as to the 

 fitness of each formation for being pierced by a tunnel. The in- 

 vestigations on which the paper was founded were mostly undertaken 

 from no practical point of view and before a Channel tunnel was 

 thought of. 



Dr. Prestwich's inaugural address as professor at the University 

 of Oxford, in January, 1895, was on the Past and Future Work of 

 Geology. We had no reason to suppose, he held, that during the 

 greater part of the geological periods life in one form or another 

 was not as prolific, or nearly so, in the British areas as at the present 

 day. We might thus form some conception of how little relatively, 

 though much really, we had so far discovered, and of how much 

 yet remained to be done before we could re-establish the lands and 

 seas of each successive period, with their full and significant popu- 

 lations. This we could not hope ever to succeed in accomplishing 

 fully, for decay had been too quick and the rock entombment too 

 much out of our reach ever to yield up all the varieties of past life; 

 but, although the limits of the horizon might never be reached, the 

 field could be vastly extended; each segment of that semicircle 

 might be prolonged we knew not how far; and it was in this exten- 

 sion this filling up the blanks in the life existing in each particular 

 period that one great work of the future lay. The speaker then 

 considered two objections which had been urged against what had 

 been called the cataclysmic theory in opposition to the unif ormi- 

 tarian theory both terms characterized as objectionable in their 

 exaggeration: one, that we required forces other than those which 

 we see in operation; and the other that it was unnecessarily sought 

 in that theory to do by violent means what could be equally well 

 effected by time. The question raised in this theory is not, how- 

 ever, as to the nature of the force, but as to its energy; not a ques- 

 tion of necessity one way or another, but of interpretation, of dy- 

 namics and not of time ; and we can not attempt the introduction of 

 time in explanations of problems the real difficulties of which were 

 thereby more often passed over than solved. Time might and must 

 be used as without limits; there was no reason why any attempt 

 should be made either to extend or control it; but while there was 

 no need for frugality, there was no reason in prodigality. After all, 

 it would be found that, whichever theory was adopted, the need 

 would not be very difficult. The mountain range, for the gradual 



