If the base of the Maastrichtian Stage is placed at the first appearance ofthe belemnite Belemnella lanceolata in Western Europe, the boundary between the Campanian and Maastrichtian stages in the U.S. Western Interiormay lie between the zones of Baculites jenseni and Baculites eliasi. The B. jenseni Zone can be shown to be latest Campanian in age on the basis of the occurrence of Nostoceras (N.) hyatti Stephenson and Jeletzkytes nodosus (Owen), which range to the top of the Campanian in the well-dated Vistula Valley sequence in Poland, but disappear before the first appearance of B. lanceolata. So defined the numerical age of the Maastrichtian lies between 73.2 ± 0.7 and 70.1 ±0.7 Ma, based upon dates from high temperature chronometers in bentonites in the Western Interior.

Fossil megaspores of the aquatic fern Azolla tegeliensis Florschütz have been recovered from sediments of early Pleistocene age at Great Blakenham, Suffolk, England. This discovery is the first record for this taxon in the British Isles. The find reinforces a recently suggested correlation of the British early Pleistocene sediments with those from con tinental northwest Europe. In the long continuous Pleistocene sequences in The Netherlands the megaspores of A. tegeliensis have been recovered from early Pleistocene sediments, where they are restricted to the Tiglian Stage. Sediments at Great Blakenham can now be correlated with the Tiglian sediments of The Netherlands.

The Aberystwyth Grits Group was the first in a series of southerly-supplied sandstone-rich turbidite systems that invaded the Welsh Basin during the Telychian Stage (late Llandovery; Silurian). Structural and stratigraphical evidence indicates that deposition of the sand-dominated parts of the system was largely restricted to the east by a zone of syndepositional faulting, now marked by a major vergence divide. Downfaulting and reverse drag along the fault hangingwall created a bathymetric low, which focused deposition of high-density, sand-carrying turbidite flows and flow components, allowing substantial thicknesses of sediment to accumulate. In contrast, low-density, mud-rich turbidites were deposited over a wider area, enhancing the topographic relief generated by uplift above the fault footwall, to form a feature which restricted the spread of the coeval easterly-supplied turbidites of the Devil's Bridge Formation.

Since 1976 the Lower Silurian Grogal Sandstones of the Welsh Basin have been interpreted as contourites. Here we show that they are in fact fine-grained turbidites, frequently with pale-coloured oxidized top layers which enable distinction of individual event deposits. As reported previously, palaeocurrent directions derived from ripple cross-lamination are typically at a high angle, often close to perpendicular, to those measured from sole structures. The favoured explanation is that ripples migrated under transverse internal waves generated at an intrabasinal slope to the east. Evidence for the lateral confinement of the overlying Aberystwyth Grits by such a slope provides support for this explanation.

During early Ordovician times volcanic and high-level intrusive activity occurred at numerous centres across North Pembrokeshire. Previous work suggested a geochemical transition in this activity from calcalkaline through to tholeiitic with time. However, new data indicate more extensive calc-alkaline magmatism and that both magma types were coeval. The origin of the calcalkaline magmas remains equivocal, but the tholeiitic magmas appear to have been derived from a source similar to N-type MORB, variably modified by supra-subduction zone fluids, combined with some fractionation during ascent. These data are consistent with emplacement in a supra-subduction zone marginal basin.