By the death of Professor Huxley another illustrious name must now be inscribed on the walls of our Valhalla, while the world of science mourns the loss of one of its most distinguished leaders, who shares with Owen and Darwin the reputation of having done more to advance the study of biology than any other of the naturalists who have appeared within the present century.

In a letter to this Magazine of May, 1895, headed “The Indentation of the Bunter Pebbles,” Mr. W. S. Gresley criticizes the summing-up of my views, given in the ‘Annals of British Geology’ (1892, p. 52), that “The indentation of the pebbles he considers to be the result of contact-solution, the water being retained at these spots by capillary attraction.” It would have been more satisfactory if Mr. Gresley could have read my original paper before penning his letter, as he would then not have assumed that I “adduce no evidence in support of the chemical theory.”

The opinion that fossil Radiolarians were entirely limited to Tertiary strata prevailed until a comparatively late period. Prof. Ernst Haeckel, in his monograph on the Radiolaria, published in 1862, says “that the Radiolarians made their appearance for the first time during the Tertiary period”; and Ehrenberg, as late as 1875, defined all the Polycystina-bearing rocks as Tertiary.

“Even if marine life had been prolific, and the old sea-bottom more or less well covered with sedimentary deposits, it does not follow,” says Dr. Geikie, “that the Boulder-clay of the succeeding mer de glace should now contain any shells” (p. 141).

From what has been said, it appears that the absence of all traces of the sea at a similar level, and at many approximate levels, all round the country, and the absence of relics of marine life, more or less abundant, in the Upper (or supposed post-submergence) Bouhler-clay, are insuperable difficulties against accepting the alleged submergence of 500 to 600 feet—that is to say, difficulties which have resisted all attempts to explain them away.

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.

Over the area in question the total thickness of the Chalk (where it can be measured from top to bottom, or nearly so) varies from 623 feet at Streatham to 1146 feet at Norwich, and in the latter case the topmost beds are absent; so that the full thickness, in some parts of Norfolk, may be 1200 feet or more. This figure, however, is exceptional, the nearest to it recorded being 890 at Harwich [this should probably be 895, the Glauconitic basal bed having been called Upper Greensand]. At East Horsley, in Surrey, a thickness of 817 feet has been proved, but generally speaking we find less, and over a large area 700 feet is not reached. It seems that the Chalk thins toward London (where 650 feet may be taken as about the usual thickness), not only from north and south but also from east and west. [It may be well to add the thicknesses proved by other borings outside London. These are as follows, where the borings have passed through the whole formation, from the overlying Tertiary beds to the underlying Upper Greensand or Gault:—Loughton 651 feet, Richmond 670, Cheshunt 681, Chatham and the neighbourhood 680–684, and Winkfield, near Windsor, 725. In sundry places where the topmost beds are missing we have the following:—Bushey (Herts) 686, Chartham (Kent) 735, and Coombs (Suffolk) 817, which last-mentioned should probably be over 820, for the same reason as given above, for increase at Harwich.]

Since the appointment of the Sub-Committee upon Glacier Observations sufficient time has not yet elapsed for many exact data to have come to hand, with one very brilliant exception— that of New Zealand.

Many of the preceding volumes of this well-known series may have possessed a wider interest, but few, if any, are of greater value, or will more profoundly influence the progress of seismology, than that which is now before us. This evidently is a work which is neither to be “tasted” nor “swallowed,” nor even to be “chewed and digested.” It is intended for those who make books, not for those who read them. It will be the parent of many papers. For in these somewhat unattractive-looking pages are gathered materials for the harmonic analyzer and facts for the student of terrestrial evolution. Only the labour is required, and that will soon be forthcoming, and we shall know something about the laws which govern the distribution of earthquakes in space and time, at any rate in the country where they have been most widely and successfully studied.