This note is a record of the occurrence and character of some curious marks on a rock surface near Borth, Cardiganshire. We do not know of any previous description or reference to marks of this kind.

Chemically similar altered gabbro, tholeiitic basalt, basaltic andesite and calc-alkaline rhyolite of Early Miocene age is present on Small Nggela, Solomon Islands. Large vesicles are invariably lacking from the autochthonous basaltic pillow lava which has narrow chilled margins, but clasts of allochthonous basalt present in coeval Early Miocene sediment are commonly vesicular. This suggests that the autochthonous lava was deposited in deep water (> 2.5 km) whereas the allochthonous lava was formed upslope in shallow water. A progressive increase in the tholeiite in Zr, Ti, K2O/(K2O+Na2O), Rb/Sr and K2O/Rb from N to S confirms that an Early Miocene southward-descending subduction zone, postulated by some authors, was present. Its recognition implies that the subduction zone did not migrate far during the Early Miocene.

Very little is known of the early history of the non-marine Gastropoda; hence the discovery in the coal-bearing strata of Scremerston (Northumberland) of a small species closely resembling certain modern fluviatile operculate shells is of considerable interest. My thanks are due to Mr. J. Pringle for bringing the specimens in question to my notice; to Mr. R. G. Carruthers, to whom their discovery is due, for sending me particulars; and to Dr. F. L. Kitchin for permission to borrow them from the Museum of Practical Geology, where they are deposited.

The identification of the Rhætic Formation in Britain, previously discovered to be intercalated between the Keuper Marls and Lower Lias Shales in Germany, we owe to the labours of Dr. Wright, F.G.S., and Mr. Charles Moore, F.G.S., In the year 1860, the former published an account of the strata beneath the Lias, characterized by the occurrence of Avicula contorta; the latter, in the following year, showing in a most valuable paper the true relation of the sandstones, shales, and limestones to the White Lias above and the Keuper below, added upwards of twenty-eight new species to the list of British Fossils.

Since a “shear” is mathematically the same as a compression in one direction with a compensating expansion in a direction atright angles to it, the consideration whether slaty cleavage can be ascribed to movements of this character resolves itself into the question whether the cleaved rocks have or have not suffered a total diminution of bulk. The most convenient way of treating thequestion is by discussing, as I did in my former paper (p. 15), the form of the “ellipsoid of distortion.” The ellipsoid produced by a pure shear would be one of three unequal axes, of which the second or mean axis would be a geometric mean between the other two: whereas, if the expansion did not compensate the compression, the second axis would be greater than this geometric mean, and if the expansion were slight, the second and greatest axes would be nearly equal. The facts seem to accord with the latter supposition, and the diminution of bulk thus indicated agrees with what might be a priori expected.

Trend surface analysis has been used widely in geology and geomorphology but only rarely has it been applied to directional data. This neglect stems from the inapplicability of normal trend surface procedures to such data. An adaptation of normal trend surface procedures specifically designed for use with directional data is, however, available as a FORTRAN IV computer program. This technique is described and its usefulness in generalizing regional patterns of flow is illustrated by applying it to data representing ice flow direction in Central Scotland.

During the last two years the Coventry City Corporation has put down three boreholes, for water supply purposes, near Mount Nod Farm, on the north side of Broad Lane, 2 miles 5 furlongs W. 6° N. of the centre of the city.

The Cretaceous formation of Bahia, first brought prominently to notice by the discoveries of Allport in 1859, has been in great part examined and described by the late Professor Hartt, by Dr. O. A. Derby, by Dr. B,. Rathbun, and by Dr. J. C. Branner. Some additional observations made by the present writer were published in the Geological Society's Journal of May, 1907, to accompany Dr. A. Smith Woodward's paper on the Vertebrate Fossils of the formation.

A summary is given of the preservation and general abundance information on palynomorphs of post-Silurian age in Svalbard. An explanation of the distribution of successful and unsuccessful palynomorph extraction is attempted, with a conclusion that varying burial history under other sediment was the principal controlling factor.

Of “those precious specimens called ‘types’ which must be appealed to through all time to determine the species to which a name was originally given,”Bristol Museum contains one hundred and eighty six distinct fossil forms. With the exception of a single Coal-measure plant, these are all the remains of animals, ranging in the zoological scale from the Reptiiia to the Actinozoa, and stratigraphically from the Silurian to the Cretaceous epochs.

This important earthquake is chiefly of interest on account of its connexion with the strong Hereford earthquakes of 6th October, 1863, 30th October, 1868, and 17th December, 1896. At least three of the four earthquakes (those of 1863, 1896, and 1926) seem to have originated in the same twin-foci, the epicentre of one lying near Hereford and that of the other near Ross. The fourth earthquake (that of 1868) originated in the Ross focus, possibly also in the Hereford focus.

The late Prof. Louis Agassiz, whilst on a visit to Halifax with Prof. John Phillips, during the years in which he was preparing his “Recherches sur les Poissons fossiles,” identified the caudal extremity of a large species of Cœlacanth fish to which he appended the name of Cœlacanthus Phillipsii in honour of his friend. The specimen is from a large “baum-pot,” as the calcareous nodules are locally termed, obtained from the Lower Coal-measures. This specimen was found at the Swan Bank Pit at Halifax, and, so far as I know, is the only one which has been discovered. The surface exposed by splitting the nodule is 0.295m. diameter, and the part of the fish preserved extends across it; it consists of the caudal portion of a large individual, which, had it been perfectly preserved, would have been between four and five feet in length.

In the present communication I propose to describe the petrographical characters of some hornblende-bearing rocks which occur as intrusive sheets and bosses in the limestones and quartzites of the Assynt district. These rocks have been referred to under various names by the different writers on the geology of the district. Prof. Nicol speaks of them as greenstone and trap, and Sir R. Murchison, as syenitic greenstone. Mr. Hudleston indicates their character more definitely by speaking of them as a “kind of diorite.” Prof. Bonney, in an appendix to Dr. Callaway's paper “On the Newer Gneissic Eocks of the Northern Highlands,” describes the microscopic structure of a specimen from the Traligill Burn near Inchnadampf, and designates the rock a hornblendic porphyrite. Dr. Hoddle gives some valuable information as to the distribution of the rocks, and calls attention to the perfection of form exhibited by the hornblende in certain varieties. He gives a figure of the hornblende which shows the forms (110), (010) and (011). With regard to the relations of the rocks to the associated strata he speaks somewhat doubtfully, but evidently inclines to the view that they are intrusive. That this is the case seems proved by the absence of vesicular structure and associated tuffs, and by the fact that although they keep as a rule parallel with the bedding, cases occasionally occur in which they can be seen to move from one horizon to another.

Bibliography, etc.—This is just one of those cases where it is so difficult to choose between accepting names for forms which, though allied, are distinct, or simply lumping all the forms together under one specific designation, which does not exactly fit any of them. Objections more or less valid may be urged against either course, and some might be disposed to cut the Gordian knot by making new species all round. Buvignier went very closely into the varieties of the Corallian Cerithia. He points out that the true C. limœforme of Rœmer occurs rather higher than the Coral Rag, viz. in the “calcaire à astartes,” to which it is restricted. It is characterized by three rows of transverse granulations, just as shown in Rœmer’s enlarged figure, though at times a fourth or even a fifth very faint one is developed. It is difficult to say of what value these refinements may be, but certainly C. limœforme, as thus restricted, cannot be exactly identified in the Corallian of Yorkshire, where its place is occupied by forms slightly different, though in our collections they have been generally lumped together under the heading C. limœforme, Rœmer.

Microbially induced sedimentary structures (MISS) are microbial traces in sandy deposits. They have been formed by various modes of microbial behaviour in response to the prevailing physical dynamics in shallow-marine environments since early Archaean time. An association of fossils, phosphatic structures and grains, stromatolites and microbial laminated levelling structures is documented from the Zhongyicun Member of Lower Cambrian strata in the Baideng section dated close to 535 Ma. SEM examination demonstrates that microbial laminated levelling structures are the result of the development of microbial mats composed of filamentous structures. We propose that there was a short hiatus after the dolomite layer deposited when the dolomite layer was weathered to form centimetre-scale valleys firstly, and then microbes accumulated in these valleys and formed the microbial laminated levelling structures.

Recently an account of the endogenous contact-zone of the non-magnesian limestones at Ben Bullen was published in this Magazine (Joplin, 1935 a), and it is now proposed to examine the effects of normal contact metamorphism in the aureole of the Ben Bullen plutonic complex.