[ 425 ] 

 XXXIX. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from p. 268.] 



December 18th, 1918.— Mr. G. W. Lamplugh, F.R.S., President, 

 in the Chair. 



r PHE following communication was read : — 



-*- ' On a Bed of Interglacial Loess and some Pre- Glacial Fresh- 

 water Clays on the Durham Coast.' Bv Charles Taylor Trechmann, 

 D.Sc, F.G.S. 



A few years ago the author described a bed of Scandinavian 

 drift that was found filling up a small pre-Glacial valley-like 

 depression at Warren- House Gill on the Durham coast. This 

 section and others north and south of it have been kept under 

 observation at different times, and several new features have been 

 noticed as the high tides and other agencies exposed parts of the 

 coast. 



Towards the southern end of the old pre-Glacial valley at 

 Warren -House Gill a bed of material, varying from 4 to 12 feet in 

 thickness, was found overlying the Magnesian Limestone and also 

 the Scandinavian drift. This material has been carefully examined 

 chemically and microscopically, and proves to be identical in 

 chemical and physical characters with a sample of the true Con- 

 tinental loess. It is light brown or fawn in colour, very porous 

 and extremely finely divided, and is devoid of plasticity. Towards 

 the base, where it has not been disturbed since it was laid down, 

 it contains a number of rounded and elongated, often very hard, 

 calcareous concretions. In the cliff-section it shows little or no 

 trace of bedding, but tends to break down along vertical clefts and 

 cracks. It passes upwards into a few feet of material that consists 

 of loess which has been partly redeposited by water, and is mixed 

 with sand, gravel, and other material derived from the Scandinavian 

 drift. 



The bed of loess and redeposited loess-like drift has suffered 

 much decalcification and weathering ; near its surface there was a 

 large boulder of Norwegian titaniferous syenite which was super- 

 ficially rotted, and decomposed to a considerable depth. Smaller 

 granitic erratics in the redeposited loess are generally very much 

 rotted. The limestone rubble and stones beneath the loess are 

 strongly calcreted, apparently by material leached out of the loess. 

 In a fissure beneath the loess some mammalian bones were col- 

 lected, including astragali of two species of Cerrus. It is argued 

 that the formation and subsequent decalcification of the loess 

 deposit lying upon the Scandinavian drift indicates an Interglacial 

 lapse of considerable duration, as great as that which Continental 

 geologists call an Interglacial Period, before the overlying English 

 and Scottish drift was deposited. 



