In addition to the well-established extension, compression and transcurrent relative movements between plates of the lithosphere, this paper considers intermediate or oblique relative movements, namely, transtension and transpression. Transtension is already well established in oblique zones of ocean spreading which consist of stepped transform faults. Transpression is a more complex process. The tectonic consequences of a transpression model are outlined and it is suggested that the tectonic style in Caledonian Spitsbergen provides evidence for this transpression regime as an intermediate stage between compression and transcurrence. It is also suggested that transpression should occur generally and may relate the development of transcurrent faults in orogenic belts.

The supposed Aravalli basal conglomerate near Morchana, considered to mark an erosional unconformity above the older Precambrian Banded Gneissic Complex in central Rajasthan, is a tectonic mélange in a terrain involved in superposed deformations. The supposed pebbles represent tectonic inclusions of various shapes, formed by isoclinal folding, stretching and disruption of concordant, pre- or early-kinematic vein quartz and rare pegmatite sheets in the Aravalli mica schist during the first folding.

The Pebble Gravels of Hertfordshire are among the earliest Pleistocene deposits of the London Basin. They comprise at least three successive units, and according to the most recent published views the oldest of these is marine, the youngest fluviatile, the intermediate partly marine and partly fluviatile. In the absence of fossils these views have remained open to question. Electron microscope studies of the surface textures of sand-grains suggest, however, that they may well be substantially correct.

The dilational intrusion is described of some basalt dykes of Tertiary age into the Easdale Slates at Easdale, Argyllshire. The intrusive form of the dykes results from the walls of irregular fractures, guided by pre-existing planes of weakness, moving apart under magma pressure. The propagation of the fractures is discussed in relation to the external stress field controlling the intrusion of the dykes and the direction of opening of the fractures considered in relation to the magma pressure and the external stress field. The flow lineations developed at the margins of the dykes are discussed in terms of their mode of origin. Although the attitude of these lineations varies with the intrusive form of the dykes, the overall direction of flow of the magma was upwards to the north of northwest.

It is shown that fragments in agglomerates, which occur in chlorite schists near Tintagel, may have been both flattened and constricted. Flattening was probably associated with formation of the schistosity, and constriction with later boudinage.

The Nahan sandstone of the Nainital district is a soft, fine-grained sandstone of subgreywacke type. Like massive igneous rocks it is very well exfoliated and consists of many concentric layers. Petrographic study of different layers of this sandstone, modal analysis, grain size analysis, and size distribution of the various samples, have revealed that physical processes are mainly responsible for exfoliation of the sandstone. The study of various sedimentary parameters indicated that the provenance is from the schistose and granitic rocks of the surrounding Himalayan mountains and the material was deposited in a shallow slowly sinking basin.

Cenozoic rocks of north-western Himalayas (excluding the sub-Recent, Recent and Karewa deposits) are represented by the Subathu, Dagshai, Kasauli and Siwalik rocks, which together have a thickness of over 10,000 m and range in age from Upper Palaeocene to Middle Pleistocene. From field and laboratory investigations it is propounded that these sediments, except the Middle and Upper Siwalik, have been derived from low and medium grade metamorphic rocks, acid plutonics and sedimentary rocks of the nearby Himalayan terrains. For the Middle and Upper Siwalik rocks, detritus was supplied by sedimentary and trap rocks as well as by the underlying medium and high grade metamorphic and plutonic rocks. A major part of these sediments has been derived from the rising Himalayas rather than from the Peninsular Shield as believed hitherto. The Subathu rocks were deposited in shallow to moderately deep marine environments; the Dagshai rocks under shallow freshwater conditions; and the Kasauli and Siwalik rocks in a shallow fast-sinking basin. All these sediments accumulated under conditions of rapid erosion, short transportation and rapid deposition.

Dykes of limestone breccia, brecciated masses of limestone within vents, and intrusive relations between basalt and limestone are described as features of interest within a short distance of Beirut.

The deep-seated caledonoid lineaments which developed in conjunction with the L. Palaeozoic basins in Wales, S. Irish Sea and Co. Wexford, bounded elongated fault-blocks within the resistant basement and its cover; it is suggested that under compression these broke internally along contemporary, strike-slip cross-faults. In the Central Wales and N. Wales–SE Co.Wexford blocks the latter were principally E–W and N–S faults respectively. Repeated movements of diverse styles along members of all three suites have influenced sedimentalogic, volcanic, plutonic and geomorphologic events throughout the Phanerozoic; in particular, they permitted the Irish Sea Geanticline to rise above the roots of the Monian tectogene, and determined the form of the younger Irish Sea sedimentary basins.

The Lower Palaeozoic strata west of the Leinster Granite in eastern Ireland, normally referred to as Ordovician, are mainly a greywacke sequence which lithologically resembles undoubted Silurian rocks elsewhere to the north and west. A scanty fauna occurs which could be either Ordovician or Silurian.

A north-easterly palaeoslope is demonstrated for the south-eastern Scottish Borders during the Upper Devonian. Alkali basalt extrusion in the (?basal) Tournaisian was followed by initiation of the Northumberland basin as a structural feature. Basin subsidence gave rise to a south-easterly palaeoslope in the Southern Uplands and was coincident with the mid-Tournaisian marine transgression.

A study of the Ordovician rocks on the northern side of Abereiddy Bay has revealed that the succession is locally overturned. Consequently the stratigraphic levels of two horizons are reassessed—the Castell Limestone is placed above the Dicranograptus Shale, and the Llanrian Volcanic Series is allocated to the Lower Llanvirnian.

Boreholes at, and seaward of, Lantern Marshes shed additional information on the Quaternary evolution of the Orford, Suffolk, area. The logs indicate:

(i) a more complex surface to the London Clay, which is shown to reach depths below those formerly thought;

(ii) the reality of the lower planation surface previously recorded. The surface is, however, cut across Scrobicularia and Butley (Red) Crag to a greater extent than anticipated. It proves that at least part, and probably all, of the −8.5 to −11 m surface is post Ludhamian.

(iii) a peat sample from −9.4 m indicates that relative mean sea level at 7010 B.P. was at approximately −10.7 m. The peat is overlain by shingle and confirms the residual shingle structures as later than that time.

Detailed studies by Flett and Green have shown the Lizard complex to be a deformed body of considerable complexity. One of the principal results of the deformation has been the recrystallization of the primary peridotite. New evidence is presented concerning the original features of this high temperature peridotite. It is concluded that in some of the primary rocks there is preserved the structure and texture of the crystallization of an interstitial pore liquid trapped within a primary framework of olivine crystals.

A detailed gravity survey, carried out to determine the thickness of the Bovey Tracey beds, is described. After removal of the regional gradient a residual gravity anomaly of – 15 mgal can be attributed to the Bovey beds. This has been interpreted assuming that the clay density increases with depth and a maximum Bovey bed thickness of 1245 m is predicted. The western contact of the basin is shown to be faulted with dips of up to 63° and is possibly an extension of the Lustleigh–Sticklepath fault system.

Petrographic and geochronological studies of the rocks of Bulland Hill, an inlier of basement in the Punjab alluvium, are reported. Acid and basic pyroclastic and high-level intrusive types give an Rb–Sr isochron age of 870±40 million years. The previous correlation with the Malani Rhyolite Series of north-western India must be abandoned.

A porphyry boulder from the Permo-Carboniferous boulder bed, probably a tillite, in the Salt Range has the same age as the Bulland Hill rocks.

Gentle folding or warping, of Lower Oligocene age, pre-dating the main post-Hamstead Beds folding, is indicated where the Bembridge Marls rest unconformably on eroded Bembridge Limestone. The folding appears to have been along generally NW–SE trending axes. This trend is compatible with penecontemporaneous and even earlier folding in Southern England and adjacent parts of north-western Europe. In Southern England, the main folding may have been earlier than the Miocene age generally accepted.

The sand/matrix ratio technique is described and has been shown to provide a rapid method of correlating till units in the Cumberland lowland which belong to separate glacial phases. Basal tills have a relatively constant sand/silt-matrix ratio compared with flowage tills in the same locality.

Pleistocene silty mudflow deposits mantle much of the valley sides and floors of the Balcombe area of the central Weald. Boulder deposits at the foot of cliffs formed of resistant bedrock sandstones are also of Pleistocene age. One well sorted sand from a gentle valley side shows surface grain textures under the scanning electron microscope indicative of wind action. The superficial deposits formed under periglacial conditions, and their distribution indicates most of the landforms are relict Pleistocene features.

Tillite and other glacial rocks have been found at the base of a sedimentary sequence in the northern part of Tigre Province, Ethiopia. Their glacial origin cannot be doubted, for in addition to beds of tillite containing abundant striated boulders, glaciated bedrock has been found. The rocks are correlatives either of the Upper Carboniferous glacial rocks of southern Africa or of Ordovician glacial rocks recently mapped in the Hoggar District of southern Algeria.