The subject of the present memoir occupies a distinguished position as lecturer and teacher of our science in the University of Cambridge, one which he has held for more than thirty years, and he is well known among geologists generally as a high authority on the Palæozoic rocks, his writings being recorded in the “Quarterly Journal” of the Geological Society (of which Society he has filled the offices both of Secretary and President). His name has also frequently appeared as the author of important papers in the GeologicalMagazink and other works.

The sands which are the subject of this investigation were taken from various parts of the Wealden area, and from different horizons, though all, except the French ones, are below the Weald Clay and represent the lowest division of the Cretaceous rocks, that is, the Hastings Beds.

Remains of Echinoderms are so rare in the Hartwell Clay of Buckinghamshire, and when found so fragmentary, that it may be worth while drawing attention to a small piece of an Echinoid test recently obtained from the Hartwell Brick-pit by Mr. Edwin Hollis, F.Z.S., curator of the Aylesbury Museum, and presented by him to the national collection (Brit. Mus., Geol. Dept., E 12241). The terminology of the following description is that defined on pages 59–65 of my “Triassic Echinoderms of Bakony”, Budapest, 1909.

In the preceding paper I described the crystalline rock-areas of the Maritime and Cottian Alps: I now proceed to briefly review those of Northern Piémont forming part of the Grajan and Pennine Alps, under three heads—

I. The Lanzo Valleys and Gran Paradiso Groups.

II. The Dora Baltea (Val d'Aosta) Area.

III. The Lanzo, Ivrea, and Val Sesia Area.

They are shown in the sketch-map, Fig. 1. The conclusions in reference to the combined areas of the Piémontese Alps will be stated at the end of the present paper.

Supported by the great weight of Hutton's authority, his views, with which those of Haast and the early views of Hector were in general agreement, have gained wide acceptance, notwithstanding the opposition of McKay. Marshall, for example, as late as 1911 wrote as follows: “The great elevation [Mesozoic orogenic movement] was succeeded by nearly as great a depression. The majestic mountain ranges were gradually lowered until nothing but a chain of islands showed above sea level. To what a great extent this movement prevailed is seen at Lake Te Anau, where the Oamaru formation, some 3,000 feet thick, rises to the tops of the mountains. At Wakatipu and in the Rangitata valley the Oamaru rocks are found in the recesses of the mountains. In the Trelissick basin and between the masses of the Kaikoura ranges there was deep water. The valleys of the tributaries of the Buller are filled with Oamaru sediments.”

It is generally agreed that the main plateau of Western Australia has probably stood above sea-level since the earliest geological times, and has perhaps been a land area since the Archæan. Marine deposits lie against its northern, western, and southern borders, but none are known upon the plateau itself; but through the depression of Lake Cowan Kainozoic marine deposits have extended northward into the Dundas Goldfield at Norseman. These marine deposits include a deep lead with sponges which were described by Dr. Hinde (Bull. Geol. Surv. W.A., No. 36, 1910, pp. 7–24, pls. i–iii) and some patches of limestone which occur on the surface around Norseman. They have been described by Mr. A. Gibb Maitland, 1908 (“Recent Advances in the Knowledge of the Geology of West Australia,” Rep. Aust. Assoc. Adv. Sci., vol. xi, p. 153, 1906), and by Mr. W. D. Campbell (“The Geology and Mineral Resources of the Norseman District, Dundas Goldfield,” Geol. Surv. West Aust., Bull. 21, p. 22, 1906).

In the year 1852 John Brown, of Stanway, published a paper on the Copford deposits (Q.J.G.S., vol. viii, p. 184), and in this includes a letter from George R. Waterhouse referring to two ‘Beaver’ teeth and the metacarpal of a Bear. One of these teeth is described and figured, and is said to differ from the beaver in being larger and also in the direction of the enamel folds. This tooth is preserved in the British Museum of Natural History at South Kensington, and I have recently had the opportunity of examining it; but the second tooth I have been unable to discover, concerning which G. R. Waterhouse says it “scarcely differs from that of the European species”.

During recent years the question of the conditions of stress and strain in the earth's crust has received a very considerable amount of attention. Perhaps one of the most fruitful lines of inquiry has been that which has aimed at determining the connexion between the varying densities of the crustal rocks and the different degrees of relief of the surface of the earth. It soon became apparent that in mountainous or elevated regions the deep-seated rocks were of less density than those beneath lowlands and seas, and it became clear that the elevated regions were sustained by the buoyancy of the lighter rocks beneath them. The theory that the earth's crust was in isostatic equilibrium thus arose.