due to the presence of material obtained from the Keuper Marls farther north. Near the Brigg, the base for perhaps four feet above the Jurassic rocks is rather sandy, and has a stratified aspect, and the browner clay is separated from the redder by a sandy band from three to four yards thick, distinctly stratified, into which each seems to pass rather gradually. The clays also often present slight indications of stratification, and a more sandy band sometimes occurs in the upper one. Both contain fragments, but these are more numerous in the lower bed. They are in all conditions, from rounded to angular, but most of them vary from angular to subangular,1 well-rounded stones being in the minority. Generally they are less than an inch in diameter, but larger specimens are not These more commonly run up to six inches, but occasionally are twelve inches, or even more.2 They consist of coal, shales (Liassic certainly, and perhaps Carboniferous), various limestones (Carboniferous, Permian, and Jurassic), many sandstones and grits (Mesozoic and Palæozoic), basalts, greenstones, and numerous felstones, often apparently from Scotland and the Cheviots, with other more distinctly crystalline rocks, such as granites, gneiss, and schists. Most of these last suggest a Scotch origin, but Shapfell granite is found, and some, as stated above, have been claimed rare. 1 Some are striated, but good examples of this marking are not common. 2 Boulders two feet or more in diameter occur, but they are rare. as Scandinavian. In other words, the bulk of the fragments indicate a drift from a quarter to the north or north-west. In the upper mass of clay fragments are less numerous, and seem to run smaller, and in both the masses the clay distinctly predominates over the fragments. From Filey Brigg to Speeton Cliff the drifts continue, and the sections exhibit two clays parted by a sandy gravel, which is frequently well stratified, and sometimes is full twenty feet thick. Here also the clays often show signs of stratification.1 The coast sections between the chalk cliffs of Speeton and of Flamborough Head, and for a long distance southwards from the latter, again afford fine exposures of the glacial drifts. These have been studied by many observers, one of the fullest and most recent descriptions being that by Mr. G. W. Lamplugh.2 On either side of Bridlington Quay,3 a boulder clay, generally of a brownish colour, is the lowest member of the group. Next comes a mass of sand, with laminæ of clay or gravelly streaks, generally well stratified, sometimes false-bedded. This is associated locally with beds of gravel or with seams of boulder clay. In other words, the mass varies much in its 1 Sometimes the clay appears to be laminated, sometimes it passes locally into sand banded with clay. 2 Quart. Jour. Geol. Soc., xlvii. (1891), p. 384. 3 The chalk on the southern side of Flamborough Head terminates in a buried cliff and beach, of which Mr. Lamplugh has given an admirable account. The section was well displayed in 1893, but not in the spring of 1894. minor details, but sands and gravels dominate. Another boulder clay follows, which, however, is better displayed on the Holderness coast. Here also the lower clay (called by Mr. Lamplugh the "Basement Clay ") may be recognised, and we can distinguish in some places at least three masses of boulder clay, separated by beds of sand or gravel, which occasionally suggest the possibility of yet further subdivision. The upper Mr. mass of boulder clay, which in Holderness is distinctly reddish in colour, was distinguished by Mr. S. V. Wood, jun., as the Purple Clay.1 Fragments are less numerous in it than in the Basement Clay. As to the correlation of these deposits with those on the Norfolk coast, different opinions have been held. Lamplugh considers the "Basement Clay " the equivalent of the "Cromer Till" in the "Lower Glacial Deposits" of that district, and the Purple Clay as nearly on the horizon of the "Chalky" or "Upper Boulder Clay" of East Anglia. Though the lithological differences between these deposits are considerable, there is very much to be said in favour of this view. Many authors have distinguished a Hessle Sand and a Hessle (Boulder) Clay in parts of Yorkshire, and have placed these at a higher level than the Purple Clay; but Mr. 1 Quart. Jour. Geol. Soc., xxiv. (1868), p. 146. 2 In the latter, shells, whole and broken, are sometimes not rare, and in it occur patches of sand containing molluscs, the bivalves often having their valves united. These have been called the Bridlington Crag. Mr. Lamplugh is of opinion that these shelly sands were not formed in situ, but are of the nature of erratics. Jukes-Browne has shown, and with this view Mr. Lamplugh concurs, that not only is this subdivision of merely local value, but also the "Hessle" deposits generally are hardly separable from the Purple Clay. On the other side of the Humber similar sections occur, but are not generally so well displayed; in short, the glacial deposits of North-East England are a group of boulder clays, and of gravels or sands, the former on the whole predominating, and the latter being more persistent towards the middle part. These gravels and sands must have been deposited under water, and they not seldom indicate the action of fairly rapid currents. show no signs of stratification; at others they have a laminated structure, the included fragments also suggesting a certain regularity of disposition, while now and again distinct interlaminations of more sandy materials occur. In other words, nothing is found irreconcilable with the idea that the clays also were formed under water, while certain phenomena require explanation if the materials were deposited on a land surface which generally was occupied by ice. The boulder clays sometimes Before leaving this subject attention may be directed to a rather remarkable line of hills which crosses the peninsula of Flamborough Head, running from Beacon Hill northward to Sanwick, and then continuing for some miles farther, roughly parallel with and a short distance from the coast, till it sinks into the glacial 1 Quart. Jour. Geol. Soc., xli. (1885), p. 114. deposits occupying the Vale of Pickering. The range FIG. 17. Supposed Moraine between Speeton and Flamborough. nitely ridge-shaped in the neighbourhood of Speeton |