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New Zealanders and Science

13 — Cotton

page 137


The early professors ably performed a much needed service in teaching science to young New Zealand, and they had their reward in the numerous scientists produced by the New Zealand university colleges. Now that science is more liberally endowed, the later professors can specialise in one branch of science, and they find that they have a little more time for their own pursuits than their predecessors could spare from the classroom. They manage, often with considerable difficulty, to make time for original research, so that the fostering of the careers of other people does not necessarily entail the sacrifice of their own. One who is an excellent teacher and who has also made a name for himself as a gifted geomorphologist is Professor C. A. Cotton.

Geomorphology — the study of changing land- forms—has only recently developed as a subject separated from geology, which itself has only been considered a pure science at a comparatively late date. Before Cotton's contributions to the new science are page 138considered, it is relevant to trace briefly the history of geology up to the early years of this century. The period from 1790-1820 has been labelled by Zittel as the 'heroic age of geology', for it was then that a systematic observation of rock structure began. The term 'geology' was first suggested by Deluc and was used in a broad sense. Werner was more precise and insisted on the term 'geognosy' for that portion of science dealing with the identification of rocks and minerals and their stratigraphic relationship, and he restricted the term 'geology' to the science dealing with the origin and history of organic creation. The two branches of science overlap considerably, but the distinction is a useful one.

William Smith*, an engineer, was the 'father of British geology'. His experience in constructing canals convinced him that the relative ages of the various strata could be determined by an examination of the fossils contained in them. He helped to lay the foundations of a new science, palæontology, and then began the long enquiry into the history of the lithosphere, or in more familiar words, the earth's crust.

Cuvier then advanced an alarming theory of the earth's history. He had followed close upon Smith in the discovery of the important deductions that could page 139be drawn from palæontology, but he was impressed by the 'disproportion between the infinitesimal changes now taking place under the eye of man, and the magnitude of the topographical and biological changes evinced in the remote past.' 'Changes of such magnitude,' said Cuvier, 'must have been the result of stupendous revolutions whose cause and effects were different both in kind and degree from any known phenomena of the present age.' His theory was known as the 'Catastrophal Theory' for obvious reasons.

Geologists, repelled by the idea of a succession of giant calamities, now attempted to prove that there existed some order and decency in the behaviour of the earth. Sir Charles Lyell was the ablest protagonist of the 'order and decency' theory. In four tremendous volumes he sought to demonstrate that all the former changes of the earth's surface are referable to causes now in operation. The first volume dealt with the influences of climate and climatic variations, the second treated of the agencies of denudation and erosion, the third told the story of the coral reef, while the fourth was devoted to bringing historical geology up to date and was published independently as Elements of Geology. This established his fame.

In the nineties geologists, headed by Davis in America and by Penck in Europe, demonstrated fully, for the first time, the extraordinary manner in page 140which the surface of the earth is still being modified by the subtle but ceaseless influences of wind, water, and ice. Their work, and its extensions to past times and buried strata, really gave birth to the new science of geomorphology. To this new science, two New Zealanders, Dr Cotton and Dr J. A. Thomson, were to make valuable contributions.

Charles Andrew Cotton, the son of a sea captain, was born and spent his first years at sea, and it has been suggested that this accounts for his later interest in the more slowly changing landshapes. He was educated at the Christchurch Boys' High School, whence he won a junior university scholarship in 1903. Cotton had one difficulty—mathematics—which he was unable to overcome in spite of the efforts of a diligent and capable mathematics master, Mr W. Walton. He went on to study geology under Marshall at the University of Otago, where he won a senior scholarship and graduated with first-class honours in geology. He was appointed lecturer and then professor of geology at Victoria University College, a post which he still holds.

Cotton found his inspiration in the remarkably diverse outlines of the New Zealand landshapes. Here ancient rock formations were uplifted from the sea in recent geological time, and have since been and are being subjected to the wearing influences of ice, weather, and volcanic action to an extent unsurpassed elsewhere. The result is that the New Zealand land page 141and sea-scape is a veritable museum of geomorpho- logical processes, since all the varied influences that alter the earth's crust are carrying on their work continually about us in comparatively accessible regions. The study and classification of these is Cotton's life work.

Cotton's early work was very much influenced by his great friend, Dr J. A. Thomson, who like himself had gained a senior scholarship and first-class honours in geology at Otago. Thomson, New Zealand's first Rhodes Scholar, was a very brilliant student, who on his return from a post-graduate course at Oxford, had been appointed palæontologist to the Geological Survey Department (1911-14) and later director of the Dominion Museum (1914-28). Cotton was a younger and perhaps less brilliant man, but a sound and pertinacious thinker. Both men had leisure to devote to geological studies, and each formed a sincere respect for the other's ability and enthusiasm. Thomson's experience at Oxford had convinced him that New Zealand held a very high, if not a leading place in the science of geology. Both men were determined that the names of Thomson and Cotton should eventually be written on the scroll of illustrious geologists, if talent and hard work brought the reward they merited. Both no doubt had the refutation of Cuvier's damnable theory in mind; but, be that as it may, the unwritten pact was made that Thomson should confound him by palæontology, page 142while Cotton, piling Pelion on Ossa, would bury him deep in geomorphology. Thomson found a fertile field for study, as the conditions under which the Tertiary rocks in New Zealand had been deposited were singularly favourable to the growth of brachiopods. He did great work among Tertiary fossils and increased the number of known species from a mere half dozen or so to over a hundred. Just as he was establishing a reputation beyond these narrow confines, he succumbed to his old enemy tuberculosis. The world is poorer for his untimely death.

Cotton, however, honoured the pact and achieved his ambition. Numerous scientific papers embodied the results of his researches and speculations, and in 1922 the New Zealand Board of Science and Art arranged for the printing of his Geomorphology of New Zealand, Part I—Systematic, which is now a text-book throughout the English-speaking geological world.

This book comprises the first complete systematic treatment of the young science of geomorphology. It describes in a straightforward logical fashion the influences of heat and cold, rain, running water, ice, wind, volcanic action, and the sea upon the land surface of the globe; for although each term used is illustrated by photographs of typical examples of the action referred to taken from New Zealand surroundings, the work is world-wide in its conception, definition, and treatment. The book supplied a framework for the study and teaching of geomorphology page 143that was hitherto lacking. Many of the 'term concepts' had been used previously by William Morris Davis, the great American scientist, but they are fully defined and delimited here, certainly for the first time in the English language. The book standardises the phraseology of the study of geomorphology, and so ranks as a classic that will enable scientists to express their speculations and conclusions in simple phrases which will be understood in all countries. Like Linnaeus in botany and Cuvier in biology, Cotton has given the new science a system of classification that will standardise research everywhere.

Cotton writes an English prose style well adapted to his subject matter. He has no ponderous involved sentences, and very little ornamentation. His is one of the few geological text-books which is not sprinkled with the phrase, 'a hundred million years'. His aim is clarity, and therefore short, incisive sentences are used throughout. He treats all natural phenomena, including earthquakes, in a measured scientific manner. The following is a fair sample of his style:

'The Cycle of Erosion.—In the study of land-forms it is convenient to picture the complete series of forms developed during the process of wearing-down of the land by erosion, as land-surfaces representing practically every stage occur. The period occupied by the whole series of changes in relief produced by erosion, following the uplift of a surface of any form above sea-level is called a cycle of erosion or geographical cycle. page 144The surface upon which eroding agents begin to work is termed the initial surface; its relief is the initial relief The surface of faint relief resulting from the prolonged action of normal erosion on a land surface without interruption by uplift is termed a peneplain. . . .

'A cycle is introduced by the uplift, relative to sea level, of a portion of the lithosphere. It simplifies the elementary study of land-forms to regard this uplift as rapid. It is not to be regarded as ever sudden, or catastrophic, but it may take place so rapidly that the amount of erosion that goes on during uplift is negligible as compared with that which follows completion of the uplift. All uplifts are not as rapid as this, but the results produced by erosion will ultimately be very much the same whether the uplift is slow or rapid.'

It will be observed that though the name of Cuvier is never mentioned in polite geological circles, no opportunity is lost to rebuke him by implication.

Cotton's magnum opus is illustrated by an extraordinary range of photographs, many of them taken by himself. Where photographs would not show sufficient detail, he has supplemented them by many clear and spirited sketches. His sole concern is the clear exposition of his subject. He therefore does not dissipate his energies in attacks on his fellow geologists, who are notoriously a quarrelsome race. He is in private life one of the kindest and most sympathetic page break
(a) The imminent capture of one valley by a stream below it

A Land-Form Change From Cotton's Geomorphology of New Zealand

page 145of men and never allows an unkind word to escape him, even in geological controversy.

The author's intention was to follow up his statement of the elements of geomorphology by Part II—The Regional Geomorphology of New Zealand. The work is well in hand, but under present conditions the prospects of its being published appear remote. There would naturally be little demand for such a work outside New Zealand. The editions of Part I have sold out — largely to supply the American demand—and the book is now out of print. Professor Cotton has an enlarged and revised version now complete, and it is to be hoped that this will soon be published.

Professor Cotton's work is of vital importance to-day to a young country which has in a hundred years lost so much virgin forest that erosion is already becoming an acute problem. If through his writings and lectures he can aid in the task of convincing New Zealanders of the inevitable and ruinous consequences of deforestation, if he can acquaint them with the general principles of land change, we may be able to look to our natural resources while there is yet time.

* The centenary of the death of William Smith fell on 28 August 1939. A fine appreciation of his life and work appeared in Engineering, 25 August. It is interesting to learn that he was awarded by the Geological Society in 1831 the first Wollaston medal.