The present paper deals with sedimentary structures and palaeocurrents of the Siwaliks exposed between the Yamuna and Gola rivers, U.P., India. Typical sedimentary structures observed in the Lower and Middle Siwalik formations are: cross-bedding, rib-and-furrow structure, parting lineation, plane-laminations and worm burrows. Also the Lower and Middle Siwaliks exhibit a typical, cyclic development of sedimentary bed forms and structures characteristic of flood plain deposits. A study of cross-bedding foreset azimuths indicates south-westerly and southerly paleocurrent directions for the Lower and Middle Siwaliks respectively. Distributions of pebble orientations from the Upper Siwalik have significant preferred orientations along both N–S and E–W directions.

Glass-breccias and volcanic glass from Marysvale are shown to be welded ash-flow tuffs of rhyolitic composition. They are interpreted as resulting from intermittent volcanic activity.

Comparison of Old Red Sandstone palaeomagnetism for NW Scotland and Norway lead to the hypothesis of a 200–300 km sinistral movement along the Great Glen Fault. The displacement is thought to be of late Caledonian (late Devonian) age. The new palaeogeographic reconstruction of Northern Britain (prior to late Caledonian times) seems to have interesting geological implications.

Skip and roll marks, probably the impressions of orthocones, are described from the Aberystwyth Grits (Lower Silurian, mid-Wales).

In order to obtain further evidence for the tectonic environment of generation of the basaltic rocks of the Ballantrae igneous complex, specimens of pillow lavas, dolerites, glaucophane schists and amphibolites were analysed for Ti, Zr, Y and Nb. Using Ti–Zr–Y, Ti–Zr and Y/Nb diagrams, three different genetic groups have been distinguished – (i) hot-spot basalts round Downan Point, round Bennane Head as far N as Balcreuchan Port, and also within serpentinite around Lendalfoot, (ii) island arc low-potassium tholeiites between Balcreuchan Port and Gamesloup, and (iii) possible ocean floor basalts at Knockormal and Knocklaugh. The interrelationships of these groups are in doubt. The hot-spot basalts may have been erupted through oceanic crust, but they could have formed prior to, or subsequent to, the island arc activity. More likely, the hot-spot basalts formed (possibly on oceanic crust) at a considerable distance from the island arc, and the two were later brought together tectonically, probably at the subduction zone associated with the arc.

The Rayfield-Gona granite of the Jos Plateau, Nigeria, formerly regarded as an independent intrusive body, is now thought to be a roof facies of the Ngell granite. This explains several phenomena, such as the gradational contact between the two, and the distinctive mineral assemblage of the former.

The paper records the occurrence of ignimbrite flows at Rajula, Amreli district of Saurashtra. Three different flows of ignimbrite representing a single genetic unit have been recognized. They consist of devitrified glass shards, pumice, salic and mafic minerals and unevenly distributed basic fragments. The shards and pumice are elongated along the flow direction of the rock giving eutaxitic foliation, while the basic fragments are drawn out in the direction of flow. The low content of soda in these ignimbrites is probably due to its loss during the hydration and devitrification of the glass.

A newly discovered, mainly continental, deformed, Neogene formation – the Raham Conglomerate – records the early existence of the southern part of the Dead Sea Rift. The field relations, the predominance of clasts derived from formations which have been virtually completely eroded, and the presence of pebbles of Precambrian rocks, all attest that a considerable structural relief – possibly exceeding 2 km – already existed in the Middle (?) Miocene. Brackish marine fossils indicate that an ancestral Gulf of Elat (Aqaba) also already existed.

Basic to intermediate pyroclastic rocks of pre-Albian age are overlain by the Abakaliki shale of Asu River Group in Eastern Nigeria. The shale has been assigned Albian age on the basis of abundant (middle Albian?) ammonites found in it. It was folded (together with the pyroclastics) about a NE–SW trending anticlinal axis during the Santonian time. This new evidence of an early Cretaceous volcanism supports a pre-Albian rifting of the African shield prior to the opening of the Southern Atlantic. The latter event took place (probably in stages) during Albian time (i.e. less than 110 Ma ago), with a widespread marine transgression in West Africa and South America.

Dry starch-flour provides a light, suitably cohesive material in which slip structures can be produced. These resemble slickensides and offer some insight into one of the possible processes whereby structures occurring on natural slickensides may be produced. Steps consistently face against the movement direction. They form by the partial disintegration of temporarily coherent lumps dragged along the surface.

Margarite occurs in quartz-bearing Dalradian graphitic schists both as a primary phase and as an alteration product of kyanite. The disposition of alteration products in these rocks demonstrates clearly the role of an externally imposed gas phase in determining margarite development.