The Middle and Upper Devonian rocks of the Torquay Promontory give evidence of a volcanic phase in Middle Devonian times, recurring in the Upper Devonian, and completed by a hypabyssal phase, which was post-Culm and pre-Permian. The tuffs are basic in nature, of glass and lava fragments, cemented by calcite. The only lava recognized is a spilite, probably Upper Devonian.

Complementary rocks: a soda-porphyrite and an augite-lamp-rophyre, have been recognized at Babbacombe.

An albite-dolerite is described from Black Head, carrying small amounts of olivine and with the characteristic albite-segregation veins. This mass has been shown to include the Ilsham Manor and the Red Rocks outcrop at Babbacombe. Metasomatic change due to silicification is characteristic of its flanks: this is especially developed at Anstey's Cove, where quartz-hæmatite veins are later than the cleavage of the slates.

It has been shown that there is strong evidence for the post Culm date of this intrusion and hence for the tectonic movements of the area. The latter have been in the sequence:—tilting, intrusion, folding, thrusting, cleavage, and faulting, Some strike faults may be anterior to all these, but were repeated after the cleavage movements.

The rock surface to be described in this paper was discovered under boulder-clay during excavations for a new reservoir for the City of Cardiff Waterworks at Rhiwbina, 5 miles north of Cardiff. The relation of rock to boulder-clay proved so unusual, by reason of a curious jointing in the rock-surface, that it appeared to be worthy of record.

For many years the breccia of Western Cumberland has been known locally as “ The Conglomerate ”, under which name it figures largely in hundreds of records of borings put down in search of haematite or coal. Since, however, its components consist in general of angular and subangular rather than rounded fragments, the term “ conglomerate ” is misleading; hence the deposit is here referred to as “ Brockram ” (broken rock), a descriptive lithological term applied to rocks of similar origin in the Vale of Eden and of definite significance to British geologists.

Previous to the year 1913 the English Kimmeridge Clay was divided into two zones only, which were believed tq be “intimately blended”. In 1913 Dr. H. Salfeld instituted a more detailed subdivision of eleven zones, the upper three of which constitute the Upper Kimmeridge Clay as since defined by Dr. F. L. Kitchin. Salfeld's sequence of zones was emended in 1922 by Messrs. Chatwin and Pringle, who showed that at Swindon the zone of Pectinatites pectinatus (Phill.) occurs below the Swindon Clay, and not above it, as Salfeld had supposed. In the early part of last year Mr. S. S. Buckman also presented a similar scheme of zones, and subdivided Salfeld's zone of P. pectinatus, which he placed in the Lower Portland, as in Salfeld's original scheme.

Contaminated igneous rocks [1, pp. 177–83; 2, pp. 446–86; 3, pp. 128–46] are those resulting from the solidification of a magma which has been modified by reaction with xenoliths, usually of sedimentary origin. The Younger Gabbro masses of North-East Scotland provide what are probably the best examples of this phenomenon yet known, and their investigation will doubtless throw some light upon current petrogenetic theory.

Dr. T. O. Bosworth has described some effects of wind and sun in producing topographical forms and in modifying the shapes of stones on the surface of the deserts of Tumbez and Paita. This paper describes certain forms of rocks and stone erosion, not mentioned in his work, from an area further north than that in which his more detailed observations were made.

Most of the exposures of Cretaceous Limestone in Jamaica were faithfully indicated on the Geological Survey map of Sawkins and Brown in 1865. They are limited in extent and occur at certain places among the complex of the older or Blue Mountain series of rocks that project from beneath the covering of White Limestone that covers the greater part of the Island. Contrary to one's common experience in many European countries the Cretaceous beds in Jamaica do not approach the sea coast in any part except near Port Antonio on the north-east coast, where the Trappean shales reach the sea; near St. Ann's Bay, about the centre; and at Green Island, on the north-west coast, where the Barrettia Limestone occurs within 2 miles of the sea. Elsewhere the sea coast is occupied by the White Limestone or beds that overlie it, with the exception of stretches along the north coast around Lucea Harbour and between Port Maria and Annotta Bay, occupied by the Carbonaceous Shales of Lower Eocene age.

In my Presidential Address to the Geologists' Association I briefly referred to the flint flakings of the Weybourne Crag of the Cromer Coast, to which attention was first directed by Mr. F. N. Haward. During several recent visits I have been greatly impressed with the richness of this site in those remarkable flakings which are now so well known from the Ipswich district.

The Carbonaceous or Black Shale or Richmond Formation of Jamaica is a deposit of considerable importance in connexion with the geological history of the Greater Antilles. R. T. Hill1 correlates provisionally the Richmond Formation, as he calls these beds, with the Scotland Series of Barbados, the oldest formation in that island, and also with certain of the Tertiary beds of Trinidad. In the present communication I shall endeavour to present some observations on the Carbonaceous Shale Series of Jamaica, together with a description of the fossils I collected in it. This series of deposits consists of a sequence of ferruginous sandstones both coarse and fine-grained, some of them very hard, others when weathered extremely friable; of impure carbonaceous limestones of a very unfossiliferous nature; of grey nodular friable shales often with carbonaceous plant-like remains in them, but scarcely any other fossils; and of coarse conglomerates which seem to occur chiefly in the lower part of the formation.

Roade cutting was considered to be one of the great works in the construction of the original London and Birmingham Railway (afterwards the London and North-Western Railway) between 1833 and 1838, being about 1½ mile in length, of considerable average depth, a good part of which consisted of hard rock—the Great Oolite Limestone.

In the following pages I have endeavoured to give an interpretation, not only of the appearance of ice ages, but also of the greater changes of climate registered in the geological record. In view of the importance ascribed in this discussion to relief, I have named the theory the relief hypothesis.

C. E. Dutton, in his paper on some of the greater problems of physical Geology (Bull. Phil. Soc. Washington, vol. xi, pp. 51–64, 1889–91), formulated his conception of Isostasy in the following words: “For this condition of equilibrium of figure to which gravitation tends to reduce a planetary body, irrespective of whether it be homogeneous or not, I propose the name of Isostasy. Isostasy is being disturbed by denudation and sedimentation …”

The Cretaceous beds of the Southern Hemisphere contain a peculiar group of Belemnites which differs from all contemporary families previously described in that a ventral groove is never present. Hitherto, the individual species have been recorded either under the generalized name of Belemnites or else as members of such pre-existing genera as Actinocamax. In 1917, however, the independence of the group was recognized by Woods, who remarked that “ It is probable that the group of species to which B. lindsayi belongs should be regarded as a special section of Belemnites ”.

To the geologist the soil is an inconvenient mantle hiding the more important material which he wishes to study. Even the drift geologist, who is more particularly interested in superficial deposits, generally dismisses the soil as lying above his zone of interest. Yet the processes which go on in the soil horizons have an importance apart from their significance in practical agriculture. The study of soils has, perhaps, suffered from its close relationship to practical affairs, for it has naturally been left to the agricultural chemist, who has been obliged to approach it with an applied bias. We have in our own country scarcely any research in which the material is treated from a purely scientific point of view and studied in the same way as rocks have been studied by geologists.

The geological structure of the British Virgin Islands correlates them indisputably with the Greater and not with the Lesser Antilles. The latter are composed essentially of Tertiary volcanic rocks of andesitic or basaltic type, with or without development of sedimentary strata which, when present, only dip at gentle angles and never show the violent effects of such dynamic forces as have been responsible for the folding and “up-ending” of the strata in the Virgin Islands. The tremendous depth of the channel separating the British Virgin Islands from the Lesser Antilles lias been ascribed to faulting, probably initiated in Pliocene times.

The work of Cleve (1), Hill (4), Vaughan (5), and others (6) in the American Virgin Islands, Porto Rico, the Dominican Republic, Cuba, Haiti, and Jamaica, indicates that the British Virgin Islands form geologically only the eastern termination of that main group of islands and have been subjected to the same earth movements as them. The evidence for attributing a Cretaceous age to the sedimentary series has already been referred to.

With regard to the age of the folding and igneous intrusion, Vaughan considers that the folding took place between upper Eocene and middle Oligoccne times, and that the intrusion of the diorites took place at approximately the same date. (7)

Wythe Cooke considers that the igneous basal complex in the Dominican Republic certainly dates from Cretaceous time, but that part is probably older. He also considers that the stresses that folded and sheared these rocks were probably active during Eocene time or earlier, and that the intrusion of the great masses of dioritic rocks probably occurred before the deposition of the Eocene sediments.

According to Hill (4), however, “in mid-Tertiary times granitoid intrusions were pushed upward into the sediments of the Greater Antilles, the Caribbean, Costa Eican, and Panamic regions.” Frazer, on the other hand (8), considered the nuclear axis of Cuba and San Domingo, and possibly of all the Caribbean islands, to be Archaean, a view upheld also by Dr. W. Bergt. (9)

There is no doubt that the key to these problems lies in the larger islands of the Greater Antilles, for it is only there that unaltered fossiliferous sediments occur and can be studied in relation to the igneous intrusion and metamorphism. There appears, however, to the writer to be nothing either in the geological or faunal evidence necessarily indicating previous land connexion at any time between the Virgin Islands and the Lesser Antilles, ahd on this matter it is hoped to furnish further evidence at a later date.