SECTIONAL TRANSACTIONS.— C. 355 



This lake, which united the Porlock cuvette with the main area, was highly 

 calcareous, and the earliest deposits were cornstones succeeded by Red 

 Marls passing up into Red and Grey Marls. 



The change in conditions of deposition and lithology is accompanied by 

 a change in the character and persistence of heavy mineral suites. 



Dr. S. E. HoLLiNGWORTH. — The gypsum deposits of the Vale of Eden 

 (12.45)- 



Recent borings north-west of Appleby have added considerably to our 

 knowledge of the Permo-Trias there, especially in the poorly exposed beds 

 between the Penrith and St. Bees Sandstones. Three distinct horizons 

 at which thick beds of gypsum or anhydrite occur can be recognised in 

 the ' Permian ' Hilton Plant Beds. 



Dr. R. L. Sherlock has successfully used such chemical precipitates as 

 a basis for correlation in the Keuper, and in the Permo-Trias of North- 

 East England. They represent periods of desiccation of considerable 

 magnitude and so are probably due to regional climatic changes. Conse- 

 quently it is reasonable to suppose that where sequences of such deposits 

 are found in adjacent areas they are correlatable. This reasoning would 

 appear to apply whether the areas concerned represent separate basins of 

 deposition or detached portions of a once continuous region of deposition. 



A comparison of the Vale of Eden sequence with that in the Durham 

 Salt-field, and with that proved in boring to the concealed coalfield of 

 South Yorkshire indicates the following as a probable correlation. 



The lowest horizon (base of Hilton Plant Beds) corresponds with 

 the lower salt (and anhydrite) horizon at the base of the Permian ' Middle 

 Marl.' The two higher horizons lying about 200 ft. higher up, and 

 separated by 10-14 ft. of marl west of the Pennines, are equivalent to the 

 upper salt (and anhydrite) horizon and the upper anhydrite respectively 

 which are usually separated by 20-30 ft. of marl. 



Correlations with the Gypsum-anhydrite horizons of the Carlisle 

 Basin, West Cumberland and Furness, indicate the probability of a lateral 

 passage from ' Permian ' Hilton Plant Beds to ' Triassic ' St. Bees Shales. 



Other facts of significance in correlations on climatic basis were indicated. 



Afternoon. 



Excursion to Ashover Inlier : quarries of the Clay Cross Iron Co., Ltd. 

 Leader, Mr. W. H. Wilcockson. 



Friday, September 3. 



Presidential Address by Prof. L. J. Wills on The Pleistocene history of 

 the West Midlands (lo.o). 



Mr. A. L. Armstrong. — Evidence for climatic variations in the Pleistocene 

 revealed by excavations at Creswell Crags, Derbyshire (11. 15). 



The stratified deposits in the Pin Hole Cave, totalling 20 ft. in thickness, 

 reveal evidence of three cold periods, separated by three periods of warm 

 climatic, or inter-glacial, conditions. All the inter-glacial phases are 

 associated with human occupation of the cave, the first and second deposits 

 containing artifacts of Mousterian culture only. In the third inter-glacial 

 phase the Mousterian culture is confined to the base of the deposit and 



