Cases of metamorphosed limestones where the calcium carbonate has been converted by contact with some igneous magma into a calc-silicate rock are by no means rare, one of the best known being the conversion of the Coniston Limestone of the Lake District by the Shap Granite into a rock with various calc-silicate and other minerals such as Wollastonite, Omphacite, etc., as described by Messrs. Harker and Marr. But as far as I know, no case has been recorded where ordinary white chalk has been similarly changed. Dr. Hibsch describes a case of baculite marl containing Foraminifera which has been altered by contact with dolerite. The Foraminifera disappear and the rock becomes a granular limestone with epidote, forming a calc-silicate hornstone. This seems the nearest case to the alteration in co. Antrim I am about to describe.

The rocks of the Parys Mountain, which lies about two miles to the south of the town of Amlwch in Anglesey, were described in 1878 by the late Mr. T. Fanning Evans, H.M. Inspector of Mines, who regarded the Parys Mountain “as an outlying piece of ground, geologically identical with the region in which the great slate-mines of Festiniog occur, and from which it differs only in being developed on a much smaller scale, and in being highly metalliferous.”

Although the succession of Cretaceous beds on Black Ven is well known and much has been written on the various members of the series, only cursory references have been made to those on Stonebarrow Cliff on the east of Charmouth, and the lower beds have never been recorded therefrom. A full list of the literature on the geology of this district, including all that has been written on the Selbornian, is given in the Survey Memoir on the “Geology of Sidmouth and Lyme Regis” and another bibliography in the account of the last excursion to Lyme by the Geologists’ Association.

In a paper read recently at a meeting of the Geological Society, Dr. Washington proposes to treat certain basalts of the Western Mediterranean basin as constituting “a hitherto unrecognised petro-graphic province, or comagmatic region, one of the most salient characters of which is the presence of salfemanes (basalts) that contain remarkably high amounts of titanium.”

It is useful from time to time to take stock of our knowledge in connection with such a geological problem as that of the fauna of the Bokkeveld Beds, so that we may ascertain to what stage in the process of its elucidation we have arrived, and may note the direction in which the evidence is pointing. An indication of the principal gaps in our knowledge may also be obtained in this manner, and new suggestions as to the more promising lines of investigation. The conclusions arrived at from such a survey may be employed tentatively as working hypotheses, but it may be premature to base upon them confident generalisations. Approaching the question of the composition, relations, origin, and distribution of the Bokkeveld fauna in this spirit of caution and with the foregoing objects in view, we find firstly that a considerable advance has been made in our knowledge of it and allied faunas during the last few years. The researches of Ulrich, Kayser, Clarke, Katzer, Thomas, and others in South America have given us an immense amount of fresh information on the Devonian faunas of that continent, and the South African fossils themselves have been studied by Lake, Schwarz, and the author. Their general poor state of preservation is a matter of regret, but the increase in the material available has cleared away some of the difficulties met with by Salter and other previous workers. Much undoubtedly remains to be learnt from work in the field, and we may expect further yields of new species from different localities in the immense area still to be explored.

Any science which cannot express its conclusions by means of number must still be regarded as in its infancy. Such an expression is the only test of precision and accuracy of thought on the part of its workers, and such important characters only develop, as in the human mind, when the romance and rashness of youth have given place to the more cautious and matter-of-fact features of maturity. It is therefore a sign of healthy development when those engaged in the study of petrology begin to turn their attention towards careful numerical calculation as a basis of classification.