The results of failry close reconnaissance mapping of siluro-Devonian to Permian geosynclinal rocks in the higher parts of the border rivers are presented. The clastic sedmiens, chiefly sandstones are described in detail. paradoxically the pre-perman sandstones, may of which might be called greywacke, or arenites, while the dark Permian sandstones, being among those least likely to be called gretwacke in the field, are overwhelmingly unsorted wackes. Turbidites of this and some European sequences are described and compared. They include arenite and wacke. All the sandstones are richly rhyolictic in lithic and mineral content, while some are rich in intraformational pelitic rock fragments. The latter were deformed at an early stage of the compaction of framework sandstones and effected considerable, even complete pore-space reduction.
The structure of the area lies chiefly in the distribution of Permian formation: a central belt of marine Permian trough sediments (including wackes) with smaller outliers of similar and fresh water Permian sediments. These probably represent originally differentiated Perrmian troughts, and all are enclosed in a recurved, sheared ae consisting chiefly of siuro-Devonian low-grade and degraded metamorphic rocks, with an intervening heavilt-deformed veneer of lower carboniferous strats in the central belt. The whole structure, through processing features indicating a complex structural history including two or nore organic movemements, has been unified by its response to a powerful opi-permian arogency. Following trough sedimentation resulting from earlier, perhaps continuous Permian compession, this resulted in a dailry symmetrical steep fan-shapped structural section possessing overturning outwards in both senses from a broad axial xone of confused and conflicting overturning, mainly in the Permian trough sediments