The main topographical features of the Gebel Akhdar are described, and attributed to various phases of marine and subaerial erosion. The tectonic structures of the Gebel are also described, and their relations to the erosional features are examined. On this basis an attempt is made to reconstruct the Late Tertiary history of the region in terms of earth-movements and erosional phases; this is a period for which normal stratigraphical evidence is almost non-existent.

A new genus and species of the Lepidocentridae is described from the Lower Carboniferous at Hook Head, Ireland.

The transformation of tillite to granite and gneiss by granitization has recently been postulated for rocks of the Mount Fitton area of South Australia. After examining the relationships in the field we have concluded that another interpretation is possible; the granites could be regarded as an older basement upon the eroded surface of which the tillites have been laid. The zone of feldspar rich rocks between the two could represent a basal arkose resting directly on the old granitic surface.

The origin of precious corundum found in the gem-bearing gravels of Ceylon has long been unknown. An occurrence of sapphire is described from a contact zone where syenite has been intruded into, and desilicated by, crystalline limestone. The process of desilication in such contact zones is considered capable of accounting for much of the gem-quality corundum of the island.

At various localities along the contact of the Moine Series with the supposed Lewisian Inlier at Glen Strathfarrar structures resembling those of a conglomerate have been described. New evidence is brought forward which suggests that these structures are of tectonic origin and were produced by the disruption of competent bands in an incompetent matrix.

The holotype of Brancoceras enniskillense Foord, 1903, is shown to be a specimen of Beyrichoceras excavatum (Phillips), 1836, the suture line of which has been misinterpreted. It is associated with Beyrichoceras castletonense (Bisat), indicating the presence of the Upper B2 subzone in the Carboniferous Limestone, of Blacklion.

The Old Red Sandstone lavas of the Perthshire Sidlaws are basalts with some andesite-basalts, andesites, and rare trachyandesite. The basalts comprise chiefly olivine-bearing flows that include feldspar-phyric and aphyric varieties; olivine-free basalts with two pyroxenes are of restricted distribution.

The significance of augite textures and their relationship to augite content in the basalts is discussed.

The lava pile is apparently composed of interdigitating lenticular flows that vary from a few feet up to about 80 feet in thickness.

Unlike most other Scottish Old Red Sandstone lava suites the Sidlaw suite is fairly fresh and, like the Eastern Forfarshire lavas, it is relatively basic.

By studying the current bedding in the hornfelsed rocks surrounding the ortho-gneisses of the Carn Chuinneag and Inchbae masses it has been possible to obtain some indication of the stratigraphic order and the nature of the folding of this part of the Moine series.

In the Hecla Hoek rocks of Prince Charles Foreland, field evidence indicates that chloritoid has developed only where conditions of extreme stress have affected pelitic rocks of a certain type. Microscopic examination confirms that many of the chloritoid-bearing rocks are extremely strained, and demonstrates that growth of the mineral was contemporaneous with movement. The distribution of chloritoid is in complete discordance with the pattern of regional metamorphism.

Chemical analyses and petrographic data are given of the eastern granites of the Mourne Mountains. It is shown that the main bulk of the granite is a uniform highly siliceous biotite-bearing type and that the intrusion of this was preceded by a smaller amount of less siliceous and more variable hornblende-bearing granite. The ferromagnesian minerals have a high iron to magnesium ratio.