Sheet-like and channel-filling conglomerates and pebbly biomicrudites occur within a sequence of cross-stratified shallow-water bioclastic limestones, the Forest Hill Formation of Late Oligocene to Early Miocene age. The largest channel, 50 m wide, 9 m deep, and at least 1.2 km long, is infilled with four separate conglomerate units of pebble- to boulder-sized limestone lithoclasts in a sparse muddy matrix (biomicrudite). Both the conglomerates and associated pebbly biomicrudites possess features characteristic of high concentration mass flows - both of laminar flow (preferred clast orientation, inverse grading or massive bedding) and of turbulent flow (normal coarse-tail or distribution grading and stratification). Clast imbrication (a- or b-axes) is suggestive of gradual deposition. Some flows travelled far enough to allow both vertical and horizontal differentiation of the coarse sediment. Facies models which have been proposed for conglomerates of deep water (turbidite) association can also be applied to the small-scale neritic conglomerates. Formation and remobilisation of such coarse grained facies in a shelf setting is attributed to eustatic sea-level changes and/or to local tectonism.

Many volcanic ash layers preserved in deep-sea sediments are the products of large magnitude ignimbrite eruptions. The characteristics of such co-ignimbrite ash-fall deposits are illustrated by two layers from the Eastern Mediterranean: the Minoan ash, Santorini, and the Campanian ash, Italy. These layers are divisible into a coarse lower unit and a fine upper unit in proximal cores. Both layers also show striking bimodal grain size distributions in more distal cores. The coarser mode decreases in median diameter with distance from source whereas the finer mode shows no lateral variation. These features are interpreted in terms of a model for ignimbrite formation by eruption column collapse. Comparable volumes of ignimbrite and associated air-fall ejecta are produced.

Sand waves are such comparatively immobile transverse bedforms because they occur in tide-induced oscillatory bottom boundary layers typified by a steady velocity-component that generally is small compared to the amplitude of the periodic part. Consequently, the net bed-material transport rates, responsible for the long-term translation of the sand waves, typically are very small compared with the larger of the instantaneous rates. Sand waves should, therefore, be marked internally by series of erosional or, under restricted circumstances, non-depositional master bedding surfaces, each such surface, together with an associated comparatively thin sediment increment, being attributable to one sand-driving tide. Studies of modern sand waves, and investigations in the stratigraphic record, lend support to this conclusion. A further consequence of the regime of intense reworking under which sand waves exist is that their component grains should be in all ways more mature, other things being equal, than particles transported the same net distance by rivers.

Techniques are described for the preparation of flexible casts of macrofossils preserved as natural moulds. Materials are discussed and the choice of two high-cost silicone rubbers justified.

This study of Silurian volcanism considers three small intrusions near Bishop's Castle, Salop, as possible volcanic feeders. Acid magma intrusive into Silurian calcareous siltstones has resulted in microgranite dykes, hornsfelsed country rock and metasomatized breccia. The intrusions are of late Wenlock age or younger, but they are relatable to other Wenlock igneous rocks in the area, and are in contrast to nearby Carboniferous basaltic rocks.

In the British Tertiary intrusive centres emplacement of cone-sheets, ring-dykes and related magmatic bodies followed in shape and sequence the pattern of Hertzian fracture produced in the country rock by the magmatic diapir. In Ardnamurchan doming of the country rock, conic fracture and intrusion of cone-sheets started the development of the intrusive centre. Following that, pressure was reduced and strain relaxation occurred which resulted in arcuate and median fractures. These fractures were later on intruded by magma, hence ring-dykes (curved flanges) were formed. Resumption of pressure initiated the second cycle of cone fractures (and inner cone-sheets of centre 2).

The metaprotaspid of the bumastine Failleana calva is similar to protaspids of scutelluids, whilst late meraspids and early holaspids of F. calva are similar to fully mature styginids. This suggests that the bumastines were derived from the styginids in the Early Ordovician and that the bumastines later gave rise to the scutelluids. Bumastus and similar Silurian trilobites are phyletic derivatives of Ordovician bumastines and not effaced scutelluids as claimed recently by Lane & Thomas. Revised diagnoses of Illaeninae and Bumastinae are presented.

Af demagnetization of the Late Precambrian or Cambrian diorites of Leicestershire reveals at least two components of magnetization in sites with stable, coherent NRM. A high remanentcoercivity component yields a palaeomagnetic pole at 141° E 63° N (A959 = 9°) in agreement with results from other Late Precambrian or Cambrian rocks in North Wales and Norway. A softer component may be of recent viscous origin, or have been acquired during Cambrian remagnetization.

The age of the youngest part of the Sholeshook Limestone Formation is reconsidered in the light of recent advances in knowledge of Ashgill trilobite faunas. A low Rawtheyan (Zone 5) age is suggested and correlations are proposed with Ashgill rocks in the SW Berwyns and with part of the Swindale Limestone Formation of Cross Fell. The Cautleyan/Rawtheyan boundary is a level at which faunal changes are sufficiently pronounced to permit reliable and precise correlation.

Sandy beaches in humid climate zones can have several structures that may be preserved if covered by aeolian sand. Many structures are caused by humidhesion. This new term is coined for the fixation of sand by wetness in the aeolian sedimentary environment. Humidhesion results in relative firmness of the sand, mimicking cementation. Erosive and accretionary humidhesion structures are described.