A thick Ordovician marine flysch succession including greywackes, conglomer- ates, siltstones and shales occurs in West Nithsdale in the Northern belt of the Southern Uplands. Five new formations of Caradoc and ?Ashgill age are defined based mainly on petrographical and lithological evidence. The proposed correlation with areas up to 80 km distant to the SW, emphasises the persistent nature of the greywacke formations in the Southern Uplands when traced along strike. It is demonstrated that the main inliers of black shale in the Northern belt cannot be simple anticlines but are closely associated with large strike faults. The position of the investigated flysch succession in the accretionary prism model for the development of the Southern Uplands during the evolution of the Caledonides is indicated and its significance assessed.

Lower Old Red Sandstone drainage of the Caledonian mountain chain in the northern British Isles converged in the region of the present North Channel between Scotland and Ireland. Calculations of possible catchment area of this drainage network suggest a major river system c. 530 km in length comparable to parts of the present day drainage network of the Himalayas. Evidence from the Lower Old Red Sandstone sedimentary assemblages in Northern Ireland and Scotland indicates that tributaries flowed NE and SW parallel to the Caledonian mountain front. These tributaries joined a trunk stream which flowed southward from present western Scotland through the southern part of the present Inner Hebrides region, and on through the region of the present North Channel and terminated in the contemporaneous Devonian sea. The coastline of this sea stretched E-W across southern Britain.

The essential drainage system established in Lower Old Red Sandstone times became re- established in Upper Old Red Sandstone times, but with a channel network with palaeoflow to the NE in Scotland. This probably joined a southerly flowing trunk stream in the North Sea region, possibly parallel with the western Scotland-Irish Sea drainage.

The migmatite complex of the Savonranta district of eastern Finland represents the combined effects of polyphase deformation, polymetamorphism and the emplacement of a series of dioritic, grandioritic, granitic and pegmatitic masses. The most significant feature in terms of both regional structure and control of neosome emplacement is a large wrench fault zone along which there has been a minimum of 30 km displacement. Its development was controlled by a stress system related to plate movement in the early-middle Proterozoic Svecokarelian orogenic belt.

Successive neosome development has been related to the extensive structural and metamorphic history of the amphibolite facies palaeosome mica schists which has been deduced from refolding and cross-cutting relationships. Rb–Sr whole-rock isotopic studies of a porphyritic granite, whose emplacement was controlled by the wrench fault regime, indicate an age of crystallisation of 1786 ± 80 m.y. The initial 87Sr/86Sr ratio of 0·7053 ± 01 shows the source region for the granite magma had a previous crustal history.

Late Devensian ice-sheet movement in the western Southern Uplands of Scotland is demonstrated by the distribution of erratics from four different bedrock sources and by glacial striae and ice-moulded landforms. This evidence shows an almost radial movement of ice from an ice-divide zone. The control of relief over ice flow and the distribution of erratics is emphasised. The distribution of erratics from two of the sources, however, shows that debris in the ice was transported only a very short distance in certain places. Abundant deposits of lodgement till occur in the vicinity of the former ice-divide. Although it is generally considered that glacial erosion, and therefore deposition, are insignificant at the centre of ice-sheets, this study suggests otherwise. It is inferred that till and erratics may be emplaced during ice-sheet build-up when conditions for erosion obtained, these deposits being protected from subsequent removal by the establishment of an ice-divide across the area. The implications for high rates of erosion in ice-sheet source areas are examined.