In a previous contribution to the Geological Magazine the opinion was put forward, based upon an examination of field evidence available in the neighbourhood of Largo, that the assumption of a Permian age for the old volcanoes of East Fife should no longer be sustained. It will be remembered by those interested in the matter, that whereas this district afforded remarkably clear evidence of contemporaneous volcanic action during Lower Carboniferous times, no confirmation was forthcoming of Sir A. Geikie's wholly different structural interpretation of an overlying unconformable sheet of post-Carboniferous ash. The purpose of this paper is to supplement the conclusions arrived at three years ago, and to note one or two additional field exposures that seem likewise to indicate contemporary eruptive activity among the Lower Carboniferous rocks of East Fife.

In the Quarterly Journal of the Geological Society for 1925 (Q.J.G.S., vol. lxxxi, p. 113) I discussed the conditions of deposition of the Stockdale Shales of Valentian age. I had intended to make a detailed study of the deposits of later Silurian age, but circumstances have prevented this. I propose to offer a few notes on the subject which may be of use to other observers.

At the commencement of the year 1925 the Post Office authorities, for the purpose of laying down telephone lines, were making a trench from the corner of Rochester Road (Camden Town) north-eastward up the Camden Road and across it into and along Murray Street in the direction of St. Paul's Road, and were laying ducts at the depth of about 10 ft. The distance from the corner of Rochester Road to a point opposite the corner of Murray Street is 160 yards, the direction north-east, with a slight rise in that direction. Previously the London County Council tramway cable ducts had been laid down to the depth of 3 ft. 6 in., but below this level the whole of the ground excavated was in an undisturbed state. The trench was 2 ft. 7 in. wide. A man-hole had been sunk at the corner of Rochester Road, another at the end of the works on the Camden Road, and a third opposite to it at the corner of Murray Street, all to a depth from the surface of more than 12 ft. In fact the Camden Road man-hole was sunk to the depth of 15 ft. 6 in., so as to enable the excavators to tunnel under the road to Murray Street in order that the stream of traffic along the Camden Road might not be disturbed.

The Lower Carboniferous rocks of the Craven Lowlands are predominantly fine-grained dark argillaceous limestones and calcareous mudstones and shales with a fauna of Zaphrentid or Caninoid phase. At various horizons and along various belts these argillaceous rocks are replaced by reef limestones and the associated crinoidal limestones, reef sands, and “calcaire grumeleux”. These lisnestones usually contain a specialized reef fauna or more rarely the standard coral-brachiopod fauna.

As a result of work on the Chalk Rock in the Hitchin district during the last two years, I have obtained several Ammonoidea which differ in certain respects from those already figured and described and include two new species.

Professor Patrick Marshall's important and interesting memoir, which has recently appeared, on the geology of Mangaia, one of the Cook Islands, inevitably suggests a comparison between this island and Rurutu in the Austral Group, which I visited in 1925, during the St. George Expedition to the Pacific, and described in a recent communication to the Geological Society. Owing to the shortness of the Expedition's stay at this island, my observations were necessarily somewhat incomplete, but I had the advantage of many conversations with Mr. S. Russell, who spent several months there in 1924, prospecting for minerals. He gave me copies of his reports, and he accompanied us on our visit.

IN 1924 I drew attention to the presence of a coarse-grained conglomerate at the base of the Gebel Moqattam, near Kait Bey. This paper contains a detailed description of the occurrence, of which at the same time I shall endeavour to determine the strati-graphical significance.

In Fig. 2, p. 68 (February, 1927), the base-line of the section should be horizontal, the stratification-plane dipping to the right.