One of the most imposing and best known exposures of glacial deposits in the north of England is the line of high cliffs along the Yorkshire coast, between Patrington and Withernsea, the highest point of the cliffs being at Dimlington Beacon. Here 140 feet of glacial material is exposed in the cliff face and the foreshore is entirely of boulder clay, the base of the deposits being a long way below sea-level. The work of this paper relates to the clays and sands in this cliff exposure. The deposits are easily distinguished as being of three varieties; at the base and along the foreshore, a dark leaden grey to black, tough boulder clay, including lenticles of sand frequently containing shell fragments; this is succeeded by a thick clay of rich purple or red colour, with noticeably more contained boulders, and near the top, much included sand in lenticles, passing into a bed of pure sand; the highest part of the cliff is of earthy clay, foxy red in colour, and with relatively few boulders. These are respectively the Basement clay, the Purple clay, and the Hessle clay. Between the Basement clay and the Purple, and at the top of the Purple clay, there are beds of sand a few feet thick; these are not to be seen at all parts of the coast, but are generally present in the highest sections. Fig. 1 is a vertical section of the Dimlington cliff, and the Roman numerals indicate the specimens petrologically examined.

The experience of several years' teaching in the interpretation of geological maps has convinced the writer of the need for some more satisfactory method of classifying faults than has hitherto obtained.

The melilite described below is an abundant constituent of a zone of reaction between dolerite and Chalk at the intrusion of Scawt Hill, Co. Antrim, Ireland. The melilite occurs both in the hybrid rock formed by assimilation of carbonate and as a constituent of the exomorphic contact zone. In the latter it is associated with spurrite, Ca2SiO4 (larnite), merwinite, spinel, and calcite. The following description applies solely, however, to the melilite of the hybrid rock.

Along the coast of North Cardiganshire, between Aberystwyth and Borth, numerous rock surfaces bearing “curious marks” have been found during the last few months. One such surface from this region has already been described, but except for a solitary fragment of rock from Transbaikalia this was apparently the only occurrence known anywhere until quite recently. The coast and inland exposures in the neighbourhood of Aberystwyth were explored at the time of the original discovery, but nothing of the same kind was found except a few indefinite traces; however, a more intensive search has now shown that these curiously-marked surfaces are by no means uncommon here.

Reticuloceras Reticulatum is the typical goniatite in the topmost beds of the Sabden Shales of Lancashire. This form is known from the Exeter district (Collins and Crick, Q.J.G.S., vol. lxvii, 1911, p. 393), but apparently the only recorded occurrence of this form in North Devon is by Wheelton Hind, who, in the report of a lecture on the correlation of the rocks in North Devon with other areas, is stated to have said, “Glyphioceras reticulatum has been obtained by Mr. Inkermann Rogers” (Proc. Geol. Ass., vol. xxi, part viii, p. 463). In the summer of 1928, Mr. Rogers was good enough to take the writer over the ground at Ilsey Beach, Lower Yelland, where he had obtained the specimen in question. The beds on this beach contain Goniatites spiralis and other goniatites, but not R. reticulatum. Inquiries at the British Museum (Natural History) elicited the information that no R. reticulatum from Devon was in the Hind Collection. As the specimen cannot be traced, confirmation is impossible. Its identity with R. reticulatum, however, is manifestly erroneous, owing to its association with G. spiralis, and with the lamellibranch, Posidonomya becheri, forms which do not survive to the top of the Bowland Shales of Lancashire.

As a result of wide recognition in recent years of extensive overfolding and overthrusting, it seems to have become generally admitted that continents have actually moved horizontally in times of orogeny; but the problem as to how and to what extent such horizontal movements were effected has continued to be an irritating cause for heated disputes and also a fertile ground for wild speculation. In making the present attempt to attack this controversial problem, it is not intended to deal with the merits or demerits of the several species of theories or hypotheses connected therewith, but simply to direct attention to certain groups of geotectonic phenomena found in Eastern Asia and elsewhere, and also to the mechanism responsible for their production as may be attested by experimental means. In this way it is hoped that mere speculation may be eliminated.