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 Palæozoic series, and deduce his conclusions as to the fitness of each formation for being pierced by a tunnel. The investigations 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 populations. 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 extension—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 uniformitarian 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, however, as to the nature of the force, but as to its energy; not a question of necessity one way or another, but of interpretation, of dynamics 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
