A recent revision of the type Ludlovian succession at Ludlow (Holland et al., 1959) has raised a number of problems concerning the classification and nomenclatureof the proposed divisions. It is here suggested that these can be resolved by adopting adual systemof classification, in which both rock-stratigraphic and biostratigraphic units are recognized. The impropriety of discarding the names Aymestry and Mocktree is established, and a plea is made for the erection of stages to aid in local and regional correlation.

The revised classification of the Ludlovian rocks is defended. It is maintained that there is no need for separate rock-stratigraphical and biostratigraphical classifications. The nine new divisions are, therefore, combined units; their number is justified by the detailed mapping and their names are dictated by the requirements of the rocks and not by an arbitrary code of rules. The old classification, using Aymestry Limestone, is considered to be still usable as a crude rock-stratigraphical classification.

The lower Torridonian in its southernmost outcrops is built of felspathic greywacke turbidites, forming a succession probably 2–3 km. thick, overlain by 2 km. of pelitic and semi-pelitic sediments containing thick, current-bedded pebbly arkose horizons, especially near the base. Sedimentary structures in the greywackes include ubiquitous grading, together with flames, load-casts, convolute bedding, and sedimentary injection, brecciation and disruption phenomena. Palaeocurrents in both greywackes and arkoses indicate a southerly derivation. The detrital mineralogy also suggests a common provenance. It is suggested that the greywackes gradually filled their depositional basin and that later sedimentation occurred in a shallow water or fluvial environment.

Three acid breccia-bodies which are emplaced within the basaltic agglomerate of the Kilchrist vent of Tertiary age are described. They are considered to be of pyroclastic origin. Petrographic evidence which relates to the probable mechanism of emplacement of the breccias is discussed.

It is shown that in the two mineral pairs discussed the metamorphic grade can be estimated from the atomic ratios (Xa = Mg/Mg + Fe + 0·175 Mn + 0·360 Ca) in garnet and Xb = Mg/(Mg + Fe) in the other mineral. The standard error of the estimation is about one-third of the temperature range of the amphibolite facies.

Where M is the metamorphic grade on an arbitrary scale, in which the lower boundary of the amphibolite facies is at 4·2 and the upper at 5·1, and K is the distribution coefficient (Xb—XaXb)/(Xa—XaXb), then the estimating equation is M = 5·6 — 1·5 log10 K.

New genera and species of microplankton from a borehole through the Speeton Clay (Lower Cretaceous) of West Heslerton, Yorkshire, are described. One genus, two subgenera and seven species of dinoflagellates, and three species of hystrichospheres, are described, and a new family of dinoflagellates, the Muderongiidae, is set up.

The type species of Amplexograptus is re-examined and is considered to include two distinct species. In neither of these is there any indication of a concavo-convex rhabdosome cross-section. A revised diagnosis of the genus is given and its relation to Climacograptus briefly discussed.

A borehole programme by Stewarts and Lloyds Minerals, Ltd., has shown that a narrow tongue of boulder clay conceals a deep steepsided valley cut into the Lincolnshire Limestone and filled with drift. Plotting of structure contours indicates that, even where thedrift is more than 100 feet thick, there is considerable “bulging” of the Upper Lias Clay.