The Ordovician pterygometopid subfamily Chasmopinae is considered to include not only Chasmops McCoy, 1849, and Uralops Ancigin, 1970, but also a number of other genera which encompass species previously referred to Chasmops. These are: Toxochasmops McNamara, 1979; Scopelochasmops gen.nov.; Bolbochasmops gen.nov.; and Rollmops gen.nov. A close correlation is shown to exist between distribution of chasmopines and lithofacies, which indicates habitation in ashallow water environment. A westerly spread of chasmopine species at various times from eastern Baltoscandia is considered to correspond with a similar spread of the shallow water environment. This is shown by the periodic appearance of members of the subfamily in the Oslo region and Britain. Thereis a general reduction in number of chasmopine species and genera away fromthe eastern Baltic.

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.

A phenomenon similar to the sand tube fulgurite has been observed in experimental work carried out to compact and sinter metal powders using high voltage discharges. The sand tube fulgurite is a fused quartz tube formed by the passage of a lightning discharge. Further experiments, in which a high voltage discharge was passed from a pointed electrode held above a large volume of copper powder, through to an earthed plate, give a copper product with the characteristic fulgurite morphology. This result suggests that the quartz sand can behave as a good conductor in the lightning discharge, perhaps due to conducting coatings on the surface of the sand particles.

The Maumtrasna Formation is a thick succession of coarse clastic rocks situated in the South Mayo Trough of western Ireland. Its upperage limit is not defined but it is post-Llanvirn in age and probably Ordovician. Several aspects of the conglomerates within the succession are compatible with the action of a glacial influence during its deposition. New evidence is presented which tends to confirm the glacial hypothesis. 10.7% of garnets separated from the matrix of the conglomerates exhibit chattermark trails. Published accounts of such trails indicate that they are only found in sediments which are glaciogenic or were derived from pre-existing glaciogenic sediments. It is suggested that the Ordovician glacial activity in the South Mayo Trough took the form of a highland glaciation which was maintained, possibly at sub-equatorial latitudes, by a continuous uplift of the source area.

The role of tubes in aa flows may be more important than previously recognized. On Etna they are commonly found in the near-vent areas of aa flows. A study of tubes associated with the 1971 Observatory Vent on Etna suggests that ephemeral boccas on the flow surface downslope of the main vent were fed by tubes.

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.

Lower Carboniferous secondary dolostones are shown to be affected by dedolomitization. The crystals of dolomite most affected are those occurring around calcite-filled rhombohedral pores within the dolostones. Dedolomitization of dolomitized crinoid ossicles also occurs. This is thought to be caused by their greater susceptibility to dedolomitization due to dolomicritization. Dedolomitization and subsequent dissolution, giving an enhanced porosity to the dolostones, are believed to be related to the present-day weathering surface.

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.