During the preparation of the second part of the Catalogue of Ammonoidea of the Trias, several hundred thin median sections of ammonites were prepared and examined. Structural features of such sections are shown to have helped in the interpretation of Didymites, Lobites, and Paraganides, and some reference is made to characters of other genera, mainly Trachyceratida.

A large basic sill intrudes the Shineton shale (Cambrian) at Maddocks Hill, east of the Wrekin, near Wellington, Shropshire. An old quarry exposes the contact and reveals that the shale close by has been recrystallized to a hard, compact hornfels, the intensity of alteration decreasing away from the contact. Thin sections show that the metamorphic effect was solely thermal, the rock having been completely recrystallized, and biotite having been generated under conditions of the amphibolite facies. The metamorphism is compared with that brought about by other basic hypabyssal intrusions.

In a previous number of the Geological Magazine Professor O. T. Jones questioned the existence of the metamorphism of the Trias in the autochthonous Alps. The authors give a reply stating accurately their observations. They also recall similar observations made by other authors.

The assemblage of facts cited enables us to assert that this metamorphism exists. The problem is very complex indeed; but the fact that this metamorphism seems to be in contradiction to the classical theories about alpine orogenesis does not allow one to deny its reality. The authors maintain that the solution of the problem must be looked for in the new ideas on “fronts” of metamorphism.

Thrusting along a shear plane at the continental margins may result in a temporary up-bulging of the margins above sea-level. During the time of exposure erosion by streams should have incised canyons which now, after isostatic readjustment of the margins, constitute the widely distributed submarine canyons. Known downwarped peneplains below the surface of continental shelves may have been developed on the bulged margins by long continued erosion. The margins may, thus, have served as- sources of some sediments now found on land and believed to have been derived from a seaward direction.

The suggestions made by previous writers are summarized, and Andersson's Solifluction Theory is discussed in detail. Reasons are given why the author believes that solifluction alone could not provide the explanation. Stone runs are shown to be largely an accident of past climate and the structure and lithology of the Upper Quartzite Series rocks. A note on the economic aspect of stone runs is added.

The Rhaetic section at Newark is described and compared with sections further south. The Lower Rhaetic is locally sub-zoned by constant bone-bed horizons. In the south-west of the area a much richer fauna occurs and the zone-fossil Pteria contorta appears lower in the succession. The explanation offered is that a lagoon phase existed in the more northerly district.

Basic hornfelses occurring at the contact of slates and olivinenorite are ascribed to influx of Ca, Mg, Fe, Ti, Mn, and P from the gabbro magma into the sedimentary rocks. This kind of basic front, unlike those postulated for acid bodies, has a basic back.

A distinction is drawn between the gneisses above the Craig, excessively shattered, and those of the Gaerwen country, now regarded as autochtonous and on a different tectonic horizon.

The sandstone injections which penetrate the Kimmeridgian strata of Eathie are described, the presence of sill-like injections being particularly noted. It is considered that the occurrence of “sandstone-sills” at Eathie is of importance in ascertaining the mode of origin of the injections of the locality. It is further suggested that the sills support the hypothesis that the injections are the result of infilling of fissures from below by sand and water.