the enquiry, he is asked what may be the approximate value in time of a ’great epoch’—­whether it means a hundred years, or a thousand, or a million, or ten million years—­his reply is, ‘I cannot tell.’”

Most of the standard writers on palaeontology had assumed that the presence in two beds at different parts of the world of the same fossils implied that the beds were contemporaneous, that they had been formed at the same time.  Huxley pointed out that the fact of identical fossils being present was, on the whole, evidence against the beds having been formed at the same time.  Even some of the older writers who believed in species having been created at definite places at definite times had seen that time must have been required for sets of animals to wander from the places in which they had come into existence.  The newer theory of evolution was equally opposed to the notion of the appearance of similar animals at the same time on far-distant parts of the earth.  For such reasons he proposed to reject the use of the word Contemporaneous as applied to rockbeds in different localities which contained the same fossils, and to replace it by the word Homotaxial, which meant no more than that the beds occupied corresponding places in the geological history of the earth.  Huxley did not pretend that these arguments were entirely original:  they represented the drift of the best geological opinion, and he seized hold of them and set them down as permanent geological truths.

In 1869, in a Presidential Address to the Geological Society, Huxley took up one of the burning questions of the day.  In the early part of the century, the discoveries of geologists had been the occasion of great distress to those good people who clung to a literal interpretation of everything in the Bible.  Long before the doctrine of evolution and the descent of man from lower animals had taken practical shape, there had been a battle royal between geologists who declared that the earth was many million years old, and had been inhabited at least by animals and plants for enormous periods, and those who clung to the traditional chronology which placed the date of creation only a few thousand years from now.  The continued progress of geology, and the sturdy championship of it by men like Sedgwick, Chalmers, and Buckland, who were at the same time reputable theologians and distinguished men of science, had decided the battle in favour of the conclusions of science, and it was accepted generally that the earth was almost indefinitely old.  At the same time, another and more strictly scientific dispute had been in progress.  The older school of geologists, looking on the face of the world, and seeing it scarred by mighty fissures, displaying huge distortions of the beds in the crust, had argued that geological change had taken place by a series of mighty catastrophes.  The tremendous results which they saw seemed to them only possible on the theory that