The distribution of Gotlandian volcanic rocks covers a narrow belt running about N. 82° W.–S. 82° E., from South-west Ireland to Bohemia. The rocks comprise rhyolites, andesites, “keratophyres,” diabases, and basalts. Their age varies from early Valentian (Brabant) to Upper Salopian (Bohemia).

The Gotlandian vulcanicity, as a whole, was independent of the preceding Taconic orogeny, neither is its distribution parallel to the main Caledonian folding. The Irish-Belgian section of the belt corresponds closely to the northern boundary of the Westphalian Zone of the Variscan folding, a structural line of fundamental character. The Anglo-Irish occurrences are related to the intersection of this line with Caledonian and Malvernian structures ; those of Belgium and Bohemia are more truly geosynclinal in character.

It is unnecessary to emphasize the clarity with which overthrust structures are exhibited in the North-West Highlands of Scotland. Publications by B. N. Peach, J. Home, and their colleagues on the Geological Survey, following upon others of slightly earlier date by C. Callaway and C. Lapworth, have opened up this wonderland of geology to visitors from all parts of the world. Exposures of an overthrust mountain front extend for 120 miles from Durness to Skye. They exhibit many variations of style, of which no single locality is fully representative. At the same time, for a short excursion there is one specially favoured district. It lies in and about the Assynt culmination, where erosion has cut back the Moine nappe for several miles behind the normal line of outcrop, and has thus fashioned an extensive semi-window, through which an intriguing view can be obtained of underlying complexities (Fig. 1). The most useful publications on this district are the Geological Survey maps on the scales of a ¼ inch, 1 inch, and 6 inches to the mile, coupled with the great North-West Highland memoir and the beloved penny Guide to the Assynt Model. The most convenient hotel is Inchnadamph at the head of Loch Assynt.

In many coalfields in the zone of Anthracomya pulchra and Carbonicola similis there is a marine band, viz. Mansfield, Yorkshire; Dukinfield, S.E. Lancashire; The Gin Mine, North Staffordshire; Rimbert, North of France; but, apart from a doubtful Lingula from the roof of the Brassy coal at Bersham Colliery, no marine fossils have previously been recorded from undisputed Coal Measures of the Denbighshire Coalfield.

The question of the age of the Northern Schist Range of Trinidad, or the Caribbean group of Messrs. Wall and Sawkins, is an important one in Antillean geology. Wall and Sawkins 3 state that “Calcareous rocks are represented by two varieties in this series, viz., crystalline limestones contained in the slates and alternating with them; and compact limestones, either quite unconnected with the schistose group, or only associated with its upper strata”. Further “The compact limestones form a portion of the LaventiUe Hills, and several islands of the gulf. Some beds to the east, situated at the base of the range, such as those of Laurel Hill, and inter-stratified in the slates, are supposed to belong to this variety; but the sections in general are not such as to indicate the precise relations of the compact limestones to the micaceous series”.

The material to be described here comprises the sponges and, a coral collected by Dr. C. T. Trechmann at Toco, Trinidad, and mentioned by him in the foregoing paper. All the specimens have been kindly presented by him to the British Museum (Natural History).

Geomokphologists seeking for bevelled surfaces and characteristic breaks of slope in large land masses have frequently utilized the Hypsographic curve to determine such features.

One of the problems left unsolved in my “Revision of the Jurassic Cephalopod Fauna of Kachh” consisted of the determination of the exact age of certain Jurassic beds that had yielded (in addition to ammonites) species of Trigonia. Among these, T. smeei J. de C. Sowerby is of unusual, general interest; and, as readers of the Geological Magazine may remember, this species has been the subject of much controversy. It was one of the species whose “morphological position, viewed from the evolutionary standpoint”, caused them to be described as Cretaceous. Thanks to the continued researches of Mr. J. H. Smith, of Bhuj, who has been good enough to send me new collections from various critical sections in Kachh, I am now in a position to add to the evidence for a Jurassic age of a number of these species of Trigonia. If it be asked why, in a work on cephalopods, I have gone out of my way to express scepticism regarding the use of species of Trigonia for correlation, I can only say that this genus happened to be represented among the ammonite material sent to me. There is no reason, so far as I can see, why Trigonia should not be quite as useful for zonal purposes as ammonites. I have been equally sceptical about Stolley’s work on belemnites. But in either case I will leave the results to speak for themselves. It seems to me that if Upper Oxfordian species like Trigonia smeei and such allies as T. tenuis, T. tra-peziformis, T. remota Kitchin, not to mention the associated Astarte, Gervillia, Cucullaea, Exogyra, etc., could be claimed to be of Cretaceous age by one of the most eminent authorities, then it is time to remind the general palaeontologist again of what workers on ammonites have realized long ago.