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CHAPTER XXV

CLOSING REMARKS

S the knowledge of geology advances, the more clearly is it seen that the phenomena of our earth are related, and that there is little chance of their being explained unless we call other sciences to our aid.

Before I commenced the study of geology in the field, my practice as an architect and engineer had naturally brought me into contact with many physical problems, and it is owing to this education that I am enabled to approach their solution from a standpoint somewhat different from that of most geologists. It is to the aid afforded by the collaboration of scientific workers in their various branches that we must now look for the advancement of one of the most interesting of studies-the history of the evolution and development of the structure of the earth we inhabit.

That this study involves thinking of a high order is to be counted to it as a merit. Whether such speculations eventually are shown to be partially right or wholly wrong, they may possess great suggestiveness and lead to nearer approximations to the truth. But before theories can be established all the underlying scientific ideas must be brought to the test of practical experiment and quantitatively investigated. In my own case I have

aimed at this method of proof, and the result is embodied in this work.

To spin theories independently of the facts of Nature is a vain and unprofitable occupation, but it is now recognised by all scientific men that a working hypothesis is needful in scientific investigation. A bare collection of facts would prove as barren as too much hypothesis. But no collection of so-called facts, however bare, can be made without a basis of underlying assumptions.

The continuity of my work in the past is somewhat hidden by being distributed through so many Journals and Proceedings of scientific societies. Few, if any, would labour through these valuable tomes to get a connected idea of the principles I have been attempting to establish. In the Origin of Mountain Ranges' and 'Chemical Denudation in relation to Geological Time' certain of my views have been expounded in a systematic and connected manner, and it is the object of this work to complete and round off these 'Principles ' and bring separate but connected investigations to a focus. Nearly the whole of the matter is original, and the greater part quite novel.

Doubtless I shall be asked why I did not include a chapter on Geomorphology and show how the present orography of the earth is largely due to denudation.

To this I reply in advance that the ground is already occupied by noted geologists, who have made themselves specialists in this study. Under

these circumstances I cannot do better than refer my readers to the work and papers of the late Beete Jukes, to W. M. Davis, Israel Russell, G. Karl Gilbert, and other English and American authors, not to omit the more popular expositions by J. E. Marr and Lord Avebury.

To have treated so wide and interesting a subject with justice would have required a large portion of a second volume, and this I was not prepared to undertake.

As a closing word I desire to apologise to those authors from whom I may have consciously or unconsciously imbibed ideas, for not specifically mentioning their names. It is very difficult to trace the origin of one's opinions. If the conceptions are good they soon get absorbed in general geological ideas and their ultimate origin is not easy to determine.

Finally, investigation proceeds at such a pace that knowledge is accumulated during the time a work is in the press which might add to the value of one's labours. To wait for such information would naturally cause never-ending delay, so I submit my little venture to my brother geologists, bespeaking from them what I feel sure will be granted, a fair consideration even for those views that do not meet with their approval.

With these few remarks I conclude my labours. Prosecuted in the intervals of professional work, they have necessarily been arduous, but at the same time they have afforded me much recreation and pleasure.

RECENT NOTES

1. Experimental Mountain Building.-After note 1, p. 195, was in type, Lord Avebury read an interesting paper to the London Geological Society (May 27, 1903, published in the 'Q. J. G. S.,' August 1903) describing An Experiment in Mountain Building.' The compression was effected in a square chamber 2 feet across and 9 inches deep. The materials acted upon were layers of carpet-baize alternating with layers of sand, the pressure applied being in two directions at right angles to each other. It is to be hoped, for the better understanding of the experiment, that Lord Avebury, in his promised further researches, will favour us with a diagram or photograph of his compression chamber.

2. Rock-shattering by Differential Expansion.-In a very suggestive paper on 'The Mechanics of Igneous Intrusion (American Journal of Science,' August 1903), Reginald A. Daly shows clearly how, by differential expansion, enormous stresses may be set up in a rock invaded by granitic or other igneous magmas. This, Mr. Daly thinks, accounts for the shattering of the invaded rock so often observed at plutonic contacts.

3. Subsidence of an Antarctic Continent.-Dr. Henry Woodward, in a very interesting Presidential Address to the Norfolk and Norwich Naturalists' Society (March 1903) entitled 'The Distribution of Life in Antarctic Lands,' reprinted in the 'Geological Magazine' (September 1903), says:

'It is probable that a very large extent of ancient land around the present Antarctic continent has been lost to us by submergence, and that the rather numerous small islands in the surrounding ocean are but the buoys or landmarks indicating large areas of more or less continuous land which has since disappeared. This is supported by the many signs of volcanic activity in recent times which these islands display. Doubtless land connections stretched from South America to the South

Shetlands, the South Orkneys, South Georgia, and to Kerguelen Island.' Also:

'That earth movements on a widely extended scale have occurred in the South is evidenced by the very late elevations and subsidences which have taken place in parts of the Andean chain and in Tierra del Fuego, also in Kerguelen Island, Eastern Australia, Tasmania, New Zealand, and the Chatham Islands.'

4. Arctic Geology: Raised Beaches, Ellesmere Land.-In a summary of the geological results of The Second Norwegian Polar Expedition in the Fram, 1898-1902,' Dr. Schei, the geologist of the expedition, says (Geographical Journal,' July 1903, p. 64): The youngest evidences of marine action are the sands and clays, with sub-fossil remains of existing marine organisms which were observed at an altitude of 650 feet all round the coasts of Ellesmere Land. The altitude to which that sea rose is indicated for the most part by the loose materials of the marine terraces, although traces of it are not wanting in the hard rock in the form of a flat shore formation, in, e.g., Baumann Fjord and to the north of the Seventeenth of May Hill (Syttende Mai Haugen). The same phenomenon is exhibited in the foreland, which, to the breadth of 1 to 3 miles, and to the height of 650 feet, encircles the plateau, especially in many localities in Eureka Sound. It is also remarkably plain to see on Graham Island.'

5. Prevalence of the Dome Form in Mountain Uplifts.Israel Russell, in a preliminary paper on the geology of the Cascade Mountains in Northern Washington, says:

'The great block of the earth's crust, 100 to perhaps 150 miles broad, and with a much greater but as yet unknown length, with an elevation of from 7,500 to 8,000 feet, from which the Cascade Mountains as we now know them have been sculptured, was a nearly flat-topped elongated dome." This is the generalised form of the Cascade region, but in portions of the uplifted area there are secondary elevations 'which are in the nature of secondary domes or protuberances on its surface and flanks.' (Twentieth Ann. Rept. of the U.S. Geo. Survey, 1898-99,' pp. 98-99. Part II. 'General Geology and Paleontology.')

6. The Original Form of Sedimentary Deposits.—In a paper under this title published in the 'Geological Magazine' (January and February 1903), the Rev. J. F. Blake seeks to show that sedimentary deposits are not thickest near to their source of