South of Clew Bay, Co. Mayo, Wenlock strata, cut off to the north by a belt of serpentine marking the Highland Boundary, are divisible into three stratigraphical groups. The succession is repeated by a syncline overturned towards the south, which is modified by north-west cross-folds. The Wenlock strata have undergone low-grade “regional” metamorphism, in spite of which fossils have been preserved at a few localities.

Two short seismic refraction profiles have been shot across the former valley of the River Teifi, above and below Cardigan, with the object of determining the depth to the rock floor. This was found to lie 75 feet below O.D. at Castle Malgwyn, near Llechryd and 107 feet below O.D. at the present estuary. These figures are consistent with the glacial history of the valley indicated by the geological evidence.

Mudstone inclusions in graded greywacke-conglomerates of Salopian age from the Slieve Bernagh Mountains, Co. Clare, are considered to have been formed by fracture of the conglomerates in the course of slumping shortly after deposition and the infilling of the resulting cavities by mud derived from the underlying beds. The attitudes of the inclusions and of associated pebble imbrication suggests that slumping took place on a slope with a northerly inclination of 10°.

This note records the presence of Eocene limestones in situ on the bed of the English Channel along an east-west line to the west of the island of Jersey. The microfauna of samples of these limestones is compared with those of some other beds of similar age. There are comments on the relevance of the above discoveries to the structural history of the area.

The lower part of the limestone succession of the Hagab Monocline in the Oman Peninsula, Arabia, is divided into the Bih Dolomite (Permian, 650 m.), Hagil Limestone (Permian, 260 m.), Ghail Limestone (Trias, 600 m.) and the Elphinstone Beds (Noric, 431 m.). The latter consists of five formations, two of which are very fossiliferous. The succession also occurs to the south in borings in the forelands of the Oman Mountains and is similar to that of the foreland of the Zagros Range of Iran.

A new instrument for the use of field geologists in orientation studies is described; the method of use is outlined and briefly appraised in comparison with common practice.

Some rocks exposed near Laig Farm, Isle of Eigg, have previously been referred to the Upper Oxfordian. In this paper their age is shown by foraminifera to be Upper Cretaceous, their petrology described and their stratigraphical significance discussed. Evidence is presented that the supposed unconformity below the Lower Corallian of North-West Scotland does not exist.

The writer was asked to examine samples of the Laig Gorge Beds to try to determine from the micro-fauna whether or not the rock was of Jurassic age, as previously thought, or younger. Seven rock samples taken from various levels within the limestone and underlying sandstone were sectioned and examined, namely:—

The form of the Beinn an Dubhaich granite was considered by Harker to be boss-like. Here evidence is put forward to suggest that it may have the form of a sheet emplaced along the Torridonian-Cambrian thrust plane. The alternative hypothesis has the merit of avoiding the serious difficulties appreciated by Harker regarding the mode of emplacement of the granite.

Tretaspis moeldenensis sp. nov. from “Bala Limestone” of Carmarthenshire is described. Almost identical forms previously referred to T. kiaeri Størmer and T. aff. kiaeri occur in the Calymene Beds of Northern England. The trilobite previously described as T. cf. kiaeri from the Phillipsinella parabola Zone of the Ashgill Series of North Wales is discussed and thought to be another new species.

Primary linear structures on plunging folds, when rotated to the horizontal about the strike of the bedding plane, are clearly not in their original “primary” directions. The amount and sign of error has been studied and a method of “plunge correction” is suggested.