Sub-surface erosion is intensely active in weathered granite debris at the scarp foot of Jebel Qasim. Powerful flushes of sub-surface water after heavy rain remove much of the decomposing feldspar partly by solution and partly by mechanical eluviation. The sedentary debris gradually contracts as the feldspar is removed and when removal is nearing completion the debris may become compacted. The compacted debris occupies less than 40 per cent by volume of the granite from which it was derived.

The upper fringing pediment around this hill is mantled by moist incoherent debris holding small local pockets of water which persist throughout the dry season. Annual recharge of this sub-surface water ensures intense weathering in the debris.

The combination of intense weathering and sub-surface erosion with ensuing contraction of the debris occurring just below the piedmont angle may be sufficient to explain the maintenance of this angle during slope retreat.

Granites of the main movement-phase of an orogenic zone form an integral part of the tectonic pattern being characteristically located at the intersection of cross- and main-folds. Here, an older granitic core pierces upwards through the anticlinal vault to form a diapir-fold in which migmatization, synchronous with movement, leads to the evolution of granodiorite. At higher structural levels where pressure is lower K-granites occur. Only at sub-volcanic levels has evidence of melting been found.

Recent hydrothermal investigations, by Bowen and Tuttle, show that synthetic haplo-pitchstones which begin to crystallize at minimum temperatures become richer in K as pressure decreases. These results are closely comparable with evidence provided by the sub-volcanic K-microgranites (migmatized Caledonian granodiorite) of Slieve Gullion, but have no application to the granodiorites.

The shell-substance of the non-marine lamellibranchs from a band in the Lower similis-pulchra Zone of Lancashire is shown to be ankerite. The same mineral also forms pockets inside certain of the shells, the pockets being developed most frequently in the stratigraphically uppermost part of the spaces between the valves. It is considered that the ankerite in the pockets has occupied spaces left by shrinkage of the original mud-filling of the shells. Chemical analyses, specific gravity, and optical properties of the ankerite are given; its composition closely approximates to (Mg2Fe)Ca3(CO3)6.

Chemical and optical data are provided on pyroxene pairs in a range of metamorphic assemblages. Tie line trends in the system CaSiO3–MgSiO3–FeSiO3 for these assemblages are compared with those recorded for plutonic igneous associations.

A study of thin sections of Thecia swinderniana (Goldfuss) shows the trabecular nature of the skeleton. It also appears that there are neither horizontal pores not vertical tubules in the walls, which are compact. A review of genera regarded by various authors as allied to Thecia leads the writer to retain in the family Theciidae only Thecia Edwards and Haime and Angopora Jones, the genus Romingerella Amsden being considered a synonym of the latter.

Upper Jurassic faunas from Wadi Hathira (Kurnub Anticline), Southern Israel, are listed and allocated to the Callovian, Lower Oxfordian, Argovian, and Sequanian.