Orthograptus obuti sp.nov. and Orthograptus insectiformis Nicholson are shown to exhibit a complex proximal meshwork developed from a much-divided virgella which closely resembles retiolitid clathrial and lacinial networks. The virgellar meshworks tend to enclose the rhabdosome, at least for the first few thecal pairs, and may support a tenuous periderm. This kind of virgellar complexity is contrasted with a newly discovered form of sicular spinosity represented by the species Glyptograptus (Pseudoglyptograptus) tabukensis sp.nov. and G. (P.) rhayaderensis sp.nov

The contents of CaO and Al2O3 in pelites from areas subjected to amphibolite facies metamorphism have been plotted in order to discover the compositional limit of the stability field of the aluminium silicate minerals. Rocks containing kyanite or sillimanite fall within a well-defined field, while rocks plotting outside this field are devoid of aluminium silicate minerals, irrespective of metamorphic grade. With the trace of the curve bounding this field known, the position of the kyanite isograd may be more easily plotted in areas where kyanite or sillimanite are rare.

The source of far-travelled pebbles in the Pleistocene gravels of the lower Axe is investigated. Reference is made to the possible introduction of far-travelled material by glacial meltwater, flowing into the basin of the Axe through a ‘gap’ in the present watershed at Chard. Gravels of the lower Axe are described and compared with gravels of the upper Axe and of neighbouring streams. Far-travelled material is found in almost all of the gravels examined. The source of the material is identified in early Tertiary gravels which occur within the present basins of the rivers in question. A glacial origin for the far-travelled material is rejected.

A pure anthophyllite schist occurs as a bedded deposit conformable with garnet-bearing quartz—muscovite, and quartz—chlorite—biotite schists and diopside-bearing caic-silicate rocks in the north-central part of the Nellore Schist Belt. Field and petrochemical studies show that anthophyllite schist has formed from regional metamorphism of Fe-, Mg-rich aluminous sediments aided by metamorphic differentiation due to local kinematic action under amphibolite facies conditions which is the general grade of metamorphism of the Nellore Schist Belt. A pure anthophyllite schist of sedimentary origin reported here is the first of its kind described from any terrain.

The post-Dharwar basic dikes from Chitaldrug and Shimoga schist belts have been analysed to determine their major, minor and trace-element composition. The comparison of the results from these formations (1.4–0.95 b.y.) with those of the early Precambrian metabasalts (2.4 b.y.), which are indicative of a thin crust at the time of their extrusion shows significant differences between them. Utilizing this and results of similar studies on corresponding formations it is suggested that the present thickness of this part of the crust might have been obtained after the extrusion of the early Precambrian basalts and before the intrusion of the middle Precambrian dolerites.