In a note published four years ago,1 I pointed out a fundamental objection to the principle of the expansion theory. That objection has been clearly expressed as follows by Prof. Leconte,2 who, like myself, considers it fatal to the theory: “Sedimentation cannot, of course, increase the sum of heat in the earth. Therefore the increased heat of the sediments by rise of isogeotherms, must be taken from somewhere else. Is it taken from below? Then the radius [or rather crust] below must contract as much as the sediments expand, and therefore there will be no elevation. Is it taken from the containing sides? Then the sides must lose as much as the sediments gain, and therefore must contract and make room for the lateral expansion, and therefore there would be no folding and no elevation.”

In a collection of Coal-measure Vertebrata made by Mr. J. Ward, of Longton, and recently acquired by the British Museum, there is an imperfect, crushed skeleton of a small Labyrinthodont from the Ash-coal Shale of Longton Hall Colliery, Staffordshire. This specimen was noticed by Miall in 1874 in his British Association Report on the Classification of the Labyrinthodonts, where it is referred to Urocordylus, some of the characters given in his diagnosis of that genus being taken from it. Some measurements of the skull were added. The same specimen was afterwards figured in Mr. Ward's paper “On the Geological Features of the North Staffordshire Coal-field” (Trans. N. Staffs. Instit. Mining Engineers, vol. x. 1890, pl. ix. fig. 2) as Keraterpetum Galvani. This figure, which is natural size, unfortunately does not show any details of the structure of the skull, some account of which may be of interest.

I Have already answered this question in the affirmative in my papers on “Metamorphism in the Malvern Hills,” though I am aware that the assertion has been contested. Nevertheless, the possibility that diorite and quartzite may have a common origin was suggested by Prof. Zirkel as far back as 1876; and in 1892 Mr. W. S. Bayley, of the Geological Survey of Minnesota, distinctly affirmed that a certain quartzite was nothing more or less than “a completely altered gabbro.” My conclusion, therefore, is not without support, and, though it has been strongly attacked, it refuses to succumb. I trust I shall be allowed in the present paper to reply to one or two of the objections to it. My remarks refer only to the Malvern area.

In the last volume of the Annals of British Geology (1893), just published, Professor Blake gives an abstract of a paper by me on “Variolite from Roundwood,” and incidentally calls attention to the discordance between the formulæ given by General McMahon, Dr. Roth, and myself, to explain the conversion of olivine into serpentine. I hasten at once to correct a slight error which occurs in my equation, but which, fortunately, does not affect the principal result of the argument, as the correct formula was used in making calculations. Amended, my equation is as follows:—

In his recent work on “Controverted Questions of Geology” (p. 159), Professor Prestwich remarks that the intense cold of the Glacial period may still be perceptible in the underground temperature gradient; that “to a certain depth the rate of cooling is now abnormally slow, owing to the excessive refrigeration the crust then underwent.” The suggestion is a valuable one, and I propose to test it in the present paper by estimating roughly the change which the temperature gradient may have experienced since the close of the Glacial period.

I Describe some facts which have attracted my attention in my neighbourhood as bearing on the question of the East Anglian Boulder-clays, and I note the directions in which these facts would seem to lead our ideas. For the most part I limit myself to my own observations.

Although, ever since the classical researches of J. D. Forbes on the phenomena presented by the Swiss glaciers were published, it has been recognized that glacier-ice behaves like a viscous liquid, and flows from high to low levels much in the same way as does a river of water, it is apparent that many who have interested themselves in the subject of glacier-flow, and have written rather dogmatically on the subject, have not clearly realized the nature of the phenomenon. Very contradictory and erroneous conclusions have consequently been arrived at, with the result that it is now somewhat difficult for those who have not made a special study of the subject to distinguish what may be fairly regarded as ascertained fact from that which is purely matter of opinion.

In the latter part of 1893 Mr. Albert Wallis, of Brigstock, in Northamptonshire, incidentally told me that he had found some well-known land shells in the Lincolnshire Oolite at Brigstock. The section from which these shells came I knew quite well, and Mr. Wallis was well acquainted with recent shells, so it seemed important to ascertain in what manner they found their way into the Oolitic Beds. Having talked the matter over with my friend Mr. Lionel E. Adams (Treasurer of the Conchological Society of Great Britain), we decided to go over to Brigstock, and examine the section and the shells, and arrive, if possible, at some explanation of their peculiar position. Accordingly, on June 16 of last year, we met Mr. Wallis there for the purpose indicated.

Since the publication of the Geological Survey Maps and Memoirs of Antrim, some additional evidence has been obtained bearing on the age of the trachyte of that district. In the year 1888, when engaged in traversing a line of section running from Belfast in a northerly direction across county Antrim to the Giant's Causeway, I was fortunate enough to notice in a large chalk quarry at Templepatrick railway station evidence which seemed to show that the trachyte was later than the Tertiary basalt sheets of the lower division; and, on further investigation into this interesting subject, additional evidence was procured that the trachytic eruption was older than the sheets of the upper series, and was, so to speak, of mid-basaltic age. Subsequently I accompanied the Director-General, Sir Archibald Geikie, on his visit of inspection to this locality, and he approved of my views. Professor Gilbert, of the United States Geological Survey, who was with us at the time, also agreed with the conclusions arrived at.

The history of every science may be compared to the ascent of lofty and diversified mountains, in which level benches and plateaux alternate with steep and rugged slopes. The first explorers, beginning at the base, toil upwards, hardly knowing which course to take, and having little idea of the country that lies before and above them. But they toil on, gathering information as they go, until, reaching a level resting-place, they can look back and form a more accurate conception of the country they have traversed. Still, they can see but a little way upwards, much less perceive the summit, but ascend they must, gaining an ever-widening view and grander and more just conceptions of the wide world below.