Plate XIV shows two photographs of a model I have recently made in order to show the outward aspect of Peloneustes philarchus, a pliosaur from the Oxford Clay. It is based on the complete mounted skeleton now in the British Museum (Natural History), Cromwell Road, a part of the well-known Leeds collection. This skeleton has a length of 10 ft. 6 in., and my model is 23 in. long, so the scale is roughly about 1:5. No other museum possesses a mounted skeleton of this genus, the nearest thing to which is the Trinacromerum, described as a Cretaceous plesiosaur by Dr. S. W. Williston in his work on Water Reptiles of the Past and Present, Chicago, 1915, where a restoration is shown on p. 89, fig. 42. The specimen is in the Museum of the University of Kansas. This same Leeds collection has given us two fine mounted skeletons of the genus Cryptoclidus, of the family Elasmosauridæ, and now we have also this fine mounted skeleton of Peloneustes, which belongs to the Pliosauridae. Hence it is now possible for geologists to see at a glance the chief characteristics of these two families, and my hope is that this model may be of some use to students of Palæontology. In making the model I have had the advantage of much valuable assistance from my friend, Mr. E. Godwin, an accomplished sculptor, without whose assistance I doubt if it could ever have been completed; for when I attempted to model the head I found a task that was beyond my power to accomplish properly, not having had any training in the art of sculpture.

In spite of Freeh's detailed work on the Devonian Aviculidæ, the application of the specific name costata to certain members of the genus Pterinea is even now a matter of some dispute, and Drevermann considers that Freeh included under this name some shells which properly belong to Pt. Pailletei De Vern. Walther and Fuchs have more recently described the internal characters. Williams has chosen the species as the type of his new subgenus Cornellites.

The rock which is described in this communication, occurs along the western flank of Llwydmor Bâch, about 6 miles eastsouth-east of Bangor, and about 8 miles south-west of Conway. On the 1 in. map of the Geological Survey, this rock, together with entirely different types on its eastern margin, are all marked as intrusive felspathic rocks. On the ¼ in. map, it is described as granite, and its eastern boundary is mapped.

The area under consideration is a portion of the mountain massif bounded on the east by the Conway River, on the north by the narrow coastal plain between Conway and Bangor, and on the west and south by the popular tourist route through Nant.-Francon pass by Llyn Ogwen and down the Afon Llugwy to Bettws y coed. The investigation includes the horseshoe-shaped ring of mountains, of which the highest is Y Foel Frâs (3,091 feet), surrounding the upper course of the Aber River (Cwm yr Afon Goch). To the north-west this igneous complex is bounded by the precipitatious crags over which the above stream descends by leaps and bounds, forming the well-known Aber Falls. Upon Sheet 78, south-east of the old Geological Survey map the area is coloured as “Massive intrusive felspathic rocks”, surrounding two oval patches indicated as “Greenstones”, whilst a further elongated patch of the latter forms the south-west boundary. The north-east boundary is limited by the Aber-Llanbedr fault. Besides the hog-backed summit of Y Foel Frâs, the area includes the similarly outlined summits of Y Drosgl West (2,483 feet), Yr Arryg (2,875 feet), Llwydmor Bâch (2,256 feet), and the more rugged summits of Bera Mawr (2,587 feet), Bera Bâch and Llwydmor (2,749 feet).

During part of the year 1920–1 the much-discussed “Middle Headon Marine” bed was again exposed in the cliffs near Milford, in such a position that there could be no doubt of its being truly in situ. No records on this subject have appeared for nearly forty years; and the recent exposure has given an opportunity of verifying the observations of earlier writers, and of explaining the discrepancies which occur in their several accounts.

Among the Brachiopoda described in my recent memoir on the Kuckers stage of north-east Estonia, there was an undetermined member of the Strophomenacea, of which the interior of the dorsal valve was unknown. I have since found a dorsal valve with its exterior (concave) outwards, embedded in kuckersite. By filling the concavity with plaster of Paris the shell could be easily removed from the kuckersite. A complete description can now, therefore, be given. Since my return to Estonia I have found additional examples of the same species and of another species of the same genus amoug the collections of the Tartu (Dorpat) Museum, which were removed into Russia during the war, and have now been returned.

Pembrokeshire is, on the whole—for Wales—a comparatively low-lying county, a somewhat dissected peneplain not usually rising much above four or five hundred feet above sealevel. Apart from the ragged stacks which rise up above the level of this peneplain in the northern part of the county—Carn Llidi and Pen-berry near St. Davids and the Stramble Head masses near Fishguard, for example—there is only one really prominent feature in the whole Pembrokeshire landscape, the Mynydd Prescelly, which rise near the western end of their ridge above Rosebush to a height of 1,760 feet.