Examination of a xenolithic minor intrusion of Caledonian age at Slievenagriddle, County Down, has shown the existence of felspathic replacement rims and rheomorphic veins associated with the xenoliths, and derived from them by metasomatic action of the magma.

Chemical and spectrographic analyses of the main rock of the intrusion, and of a rheomorphic vein, establish an order of geochemical migration for the metals of the alkali series.

In conclusion I wish to express my thanks to Mr. J. J. Hartley, of Queen's University, Belfast, for valuable advice and help in the field work; to Dr. J. E. Richey and other members of the Geological Survey for much useful criticism and assistance; to Dr. D. L. Reynolds for reading this communication in MS., and to Dr. R. L. Mitchell, of the Macaulay Institute for Soil Research, for performing the two spectrographic analyses.

In the course of examination of the non-marine lamellibranchs from British Carboniferous rocks I have for several years noted all instances of the attachment of the tubes of Spirorbis. The observations which have been made confirm the conclusions of Pruvost (1919, p. 32; 1930, p. 257) that Spirorbis in the Coal Measures is frequently found attached to plants, occasionally to marine shells, and more commonly to non-marine lamellibranchs. Of the latter, Naiadites and Anthraconauta show the greatest number of attachments; attachments to Carbonicola are not uncommon, but Spirorbis is rarely, if ever, attached to Anthracomya. Over 80 per cent of the attachments recorded by the writer from the Lower Westphalian relate to Naiadites, practically all the remainder relating to Carbonicola; in many instances, however, there were great numbers of Spirorbis attached to individual specimens of Naiadites whereas the numbers in the case of Carbonicola were generally much smaller. In the Upper Westphalian attachment to Anthraconauta is very common, and the similarity of Anthraconauta and Naiadites in this respect was urged by Pruvost as one evidence of their presumed relationship and as justification for separating Anthraconauta from Anthracomya (1930, p. 223). These conclusions I am able to endorse from these observations.

In view of the wide distribution of Gangamopteris in the Gondwana deposits of the Southern Hemisphere it is surprising that the genus has not been previously recorded with certainty from Western Australia. The only doubtful record has been published by Glauert in 1923 who found “? Gangamopteris sp.” in carbonaceous shale underlying the lowest coal seam of the Coal Measure series of the Irwin River. The occurrence of Gangamopteris in the Irwin River Coal Measures has since been confirmed by finds made in 1939 during a joint excursion with Professor E. de C. Clarke and students of the University of Western Australia. The age of the Irwin River Coal Measures corresponds most likely to that of the Greta Coal Measures of New South Wales in which Gangamopteris is well represented. Some notes on the Irwin River flora were published some time ago (Teichert 1939) and the writer hopes to present additional information at a later date.

As in Anglesey, these are numerous, dykes being there more numerous than sills. But petrologically there is far less variety, all but one of them being basic. There are no picrites, no coarse dolerites, no rhyolites, no lamprophyres.