In 1938 Roman Kozlowski published a preliminary account of a collection of dendroid graptolites and allied forms from the Upper Tremadoc of Wysoczki, Poland, upon which he had been working for many years. All of the thirty-eight species listed were new to science, as were twelve of the seventeen genera, for the reception of which he erected three new orders, Tuboidea, Camaroidea, and Stolonoidea, in addition to Nicholson's Dendroidea. Presumably, no long delay in the publication of the full monograph was anticipated; but the names have remained nomina nuda, and the only clues we have at present to the characters of the new orders themselves are slight.

Several combined link and slide devices have been described, by means of which block diagrams can be constructed from contoured maps (1, 2). Briefly, their mode of use is as follows: (a) On tracing a contour with the tracing point of the mechanical device, the drawing pencil reproduces the contour as its isometric projection, i.e. distances along the supposed line of sight are reduced relative to distances measured at right-angles to this direction, the reduction factor being determined by the angle at which the area is assumed to be viewed. (b) Before drawing the isometric projection of the next lower contour, the sheet of paper on which the diagram is being made is moved relative to the map in a direction depend-ing on the type of device by a distance which depends on the scale of the map, the contour interval, the angle at which the area is viewed, and any factor of vertical scale magnification relative to the horizontal scale which is deemed necessary to bring out the topography (2). Each successive contour is treated in this manner, preferably starting with the highest contour and finishing with the lowest. In drawing the isometric projections of the contours, such parts are omitted as their inter-sections with the higher contour projections show to be obscured by the intervention of high topography between them and the point from which the area is viewed. (c) Finally hill sky-lines are filled in, roads, rivers, etc, are drawn by sketching between the points where they have been marked as crossing contours in dealing with each contour, and such artistic additions are made as will enhance the impression of relief.

Most of the Cambrian of Arvon has the “Caledonian” strike which is dominant in Snowdonia. But there is a tract at Tregarth, about a square mile in extent, where the beds trend in any direction: that is, have no strike at all. Nothing in the beds themselves is any explanation whatever: there seems no reason for this anomaly. We have to seek an explanation in the underlying floor, and there, I think, we win some light. That floor has more than one component: Mona Complex and Arvonian. In the chapter of the Anglesey Memoir on the Age of the Mona Complex, I have thrown out a suggestion (then in explanation of nothing but the pebbles), that hills of Gwna Quartzite stood up through the Arvonian lavas. Now, in the great conglomerate of the crest and dip-slope of Y Pare, pebbles of quartzite are so numerous as to outnumber those of the rhyolite. It seems legitimate to infer that, underneath this Tregarth tract, these buried knobs of quartzite were exceptionally numerous and exceptionally high, and made the sub-Cambrian floor so uneven that the beds which rested on it could not acquire the usual strike, but were driven hither and thither, in all sorts of irregular ways. The same irregularity, though to a somewhat less degree, affects the Arvonian tuffs themselves.

An interesting zoo-geographical study of the islands and the mainland of the East African coastal region, has just been completed and the results have been published as a paper in the proceedings of the Zoological Society of London (1941). Messrs. Moreau and Pakenham in this study have raised the question of the age of the faults, which played such a large part in causing the separation of the island of Pemba. They quote Sir Edmund Teale and C. Gillman: “ There is no reason why land connections should not have persisted long after the Miocene, and probably right into the Pleistocene.” The purpose of the following article is to restate the facts and to discuss the above conclusion. In the view of the writer no new geological evidence has arisen to cause him to change his original estimate, that Pemba Island dates from the late Miocene or early Pliocene (1928).

The district to which this note refers lies on the northern front of the Sierra de la Demanda, near the eastern boundary of the province of Burgos (Spain). Here, a narrow strip of Carboniferous and Mesozoic formations, separating the Cambrian (or Silurian) of the Hercynian massif from the Tertiary of the foothills and Basin of Briviesca, has been violently disturbed in Tertiary times. The object of the note is to contribute data for the problem of the tectonics of this disturbed strip.

The rocks exposed along the road between Linstead and Guy's Hill, Jamaica, were described by Dr. C. T. Trechmann in this magazine in 1936 (pp. 259–260). The chief object of his account was to prove that the igneous rocks there were intrusions later than the associated Cretaceous and Tertiary limestones, which, according to him, had been metamorphosed into hornfelses, some of which, he stated later (1937, p. 561), he knew to have an “igneous” appearance under the microscope, “which tends to support my contention that in Jamaica we have sedimentaries altered in situ into rocks that would ordinarily be classified as igneous.” Dissent from his descriptions and interpretations was expressed by C. A. M. (Matley, 1937, pp. 501–3), the criticisms being mainly based on an examination of Trechmann's own microscope slides by F. R. A visit to Jamaica by C. A. M. in 1939 allowed him to study this road and to collect a suite of rocks for petrological examination. The results show that Trechmann's interpretation cannot be sustained. There is no granodiorite or other plutonic rock present, no metamorphism hornfelsing the sedimentary rocks, and no igneous intrusions into the Tertiary limestones.

This description is based on observations made during several months' work during 1938 and 1939, undertaken for the Government of the Somaliland Protectorate in connection with water-supplies in the barren Zeila Plain.

1. Geological observation provides abundant evidence of fractures in the upper crust, the relative displacements of the sides of a fracture being anything from a few centimetres to thousands of metres. It is generally believed that earthquakes are produced in these displacements, but little attention seems to have been given to the quantitative relations involved. The geologist sees the record of the total displacement, but has no direct information about how long it took to occur, or whether it took place all at once or by several stages. Except in cases where an earthquake has been associated with fracture of the outer surface, and we can say how much displacement occurred up to the time of inspection, he has no means of knowing whether it took seconds, hours, years, or geological periods to form. Even in these rather rare cases the displacement is not more than a few metres, and extrapolation to the larger known faults is impossible. Seismology on the other hand is well adapted to the study of sudden shifts, but the instruments do not record large movements spread over a long time; thus the geological and seismological data are largely complementary. It is known also that a large earthquake is often followed by a swarm of small ones, called aftershocks, apparently from the same focus and continuing for, possibly, several months; there may be a thousand in a single series. The geological displacement observed long afterwards will include those due to all the aftershocks, supposing, as is generally done, that they all are due to shifts on the same fault.

During a recent visit to Antigua, West Indies, Dr. C. T. Trechmann collected some fossils from the Middle Oligocene Antigua Formation, and a small but important series from the Seaforth Limestone at Seaforth. Both collections included corals. Dr. Trechmann has already published his results (1941); it is the object of the present paper to deal with the corals, and especially with those from the Seaforth Limestone, because of the conclusive evidence they afford of the age of that formation.

The preparation and utility of laminar collodion moulds for recording relief features in natural surfaces of fossil plants is well known from the writings of Professor A. G. Nathorst (1). Equally familiar is the technique of Professor J. Walton (2) for making cellulose acetate “peels” from ground and etched surfaces of rocks containing carbonized remains of vegetable tissues. More recently, similar methods have been adopted by Dr. S. Leclercq (3) for studying fossil corals, by Professor A. E. Trueman (4) for examining ammonites, and by Dr. J. K. S. St. Joseph (5) and Dr. J. Weir for the analysis of fossil brachiopods. In these several cases, ground and etched specimens were prepared, from which cellulose nitrate or cellulose acetate moulds were taken. Hitherto, however, no corresponding technique appears to have been used either for research upon inorganic rock-structures or for the investigation of surface relief-characters of minerals.

In December, 1936, I received from a Continental fellow-author of works on fossil Polyzoa, especially Cretaceous, a list of certain species described in Part III of “Further Notes on new or imperfectly known Chalk Polyzoa”, with a request that I would state the difference between them and the other species previously described which were linked with them in the list. I replied that I should always be prepared to answer such an inquiry on the understanding that the inquirer accepted as valid any answers which he could not dispute;