Reports c& Proceedings — Geological Society of London. 331 



The following communications were read : — 



1. " The Scandinavian Drift of the Durham Coast, and the General 

 Glaciology of South-East Durham." By Charles Taylor Trechmann, 

 B.Sc, F.G.S. 



The present communication summarizes observations carried out 

 for some time on the superficial deposits of South-East Durham and 

 the lower Tees Valley. It practically embraces the area represented 

 on the two Geological Survey 1 in. Drift maps, Sheet 103 N.E. 

 (New Series 27) and Sheet 103 S.E. Evidence relating to the 

 pre-Glacial levels and contours of the land in the Permian and 

 Triassic areas has been collected and examined. This supports the 

 conclusion that, immediately prior to the oncoming of glacial 

 conditions, the land stood at not less than 100 feet above its 

 present level. 



The fissures and depressions of the Middle and Upper Magnesian 

 Limestones on the eastern side of the Shell Limestone reef have 

 been instrumental in preserving relics of the material brought by 

 the earliest ice-sheet which invaded the district from the North 

 Sea. This material proves to be absolutely devoid of the ordinary 

 glacial erratics of the North of England and Scotland, found in the 

 overlying main Drifts. Several narrow vertical fissures are filled 

 with masses of red sandstone, red, grey, and green mai'l, peat and 

 masses of peaty wood, and Magnesian Limestone, both of immediately 

 local occurrence and of material strange to the district. 



The Scandinavian Drift proper occurs about midway between 

 Hartlepool and Seaham Harbour, and occupies a position near the 

 middle of the stretch of coastline where the red fissures are seen. 

 It has been preserved in a pre-Glacial depression and fissure in the 

 underlying Magnesian Limestone, extending over slightly under 

 a quarter of a mile. It is represented by a transported shelly clay 

 containing a fauna of Arctic afiinities, which recalls that of some of 

 the basement clays of Flamborough and Holderness. Among other 

 erratics, a big boulder of titaniferous syenite was found resting 

 immediately upon the Magnesian Limestone near the southern end 

 of this section ; special notice was taken also of a very big laurvigite- 

 syenite (5 feet long) and two rather smaller rhomb-porphyries lying 

 on the shore opposite this place. 



All the stones (between 300 and 400 specimens) found in this 

 clay were collected and examined. The greater part of them are 

 Avell-glaciated crystalline rocks, many of which (the typical Christiania 

 eruptives) certainly are, and the greater part may be, of South 

 Norwegian origin. Permian limestone, red sandstone, Chalk, and 

 splintered flints also occur. 



The apparent absence of any East Scandinavian rocks in Durham 

 is noticed, and an explanation offered. The early retreat of the 

 Scandinavian ice from tlie Durham coast, as also its relation to 

 tlie English and Scottish glaciation, is discussed. 



Later than the fissure-filling material are certain water-deposited 

 gravels and sands, which occupy shallow depressions underlying the 

 main Drift seen on the coast. They are noticeable for containing 



