362 STRATIGRAPHICAL GEOLOGY 



The overlying sandstones are coarse, current-bedded, red sand- 

 stones, and in the lower 100 feet they contain a few pebbles of 

 quartz and quartzite, with occasionally subangular fragments of 

 granite, felspathic grit, and lumps of hard red marl. The higher 

 beds are less coarse and more massive, and from these bones of 

 Hyperodapedon have been obtained. These beds occupy the coast 

 from the mouth of the Otter to Sidmouth (see Fig. 117). 



THE KEUPER SERIES 



This series has a much wider extension than the Bunter, and 

 its higher beds were formed in a great salt lake which covered both 

 the Bunter areas of deposition as well as all the intermediate parts 

 of Central England. Borings at several places in the Midland and 

 Eastern counties have proved that the Keuper sandstones and 

 marls extend eastward beneath the Lias and newer rocks till they 

 thin out against the western slope of the great mass of Palaeozoic 

 rocks which underlies the south-east of England. 



Thus, a boring at Burford in Oxfordshire passed through 428 

 feet of Keuper Beds, and entered Coal-measures at 1184 feet from 

 the surface. Borings near Northampton found only 60 to 70 feet 

 of Trias above the older rocks, and one at Culford near Bury St. 

 Edmunds proved its absence. It is also absent below Eichmond 

 and London, but appears to pass under the Wealden area as beds 

 underlying Lias, and believed to be of Keuper age, were traversed by 

 a boring at Brabourne in Kent. 



As in dealing with the Bunter, we shall first describe the 

 complete and typical development of the Keuper Series in the 

 Midland area, and then indicate such stratigraphical variations as 

 occur when it is traced eastward, northward, and southward. 



1. Typical Midland Area 



In this area the Keuper Series is divisible into three very 

 unequal parts : ' 



Feet. 



Red marls with rock-salt from 1000 to 3000 



" Waterstones," flaggy sandstones and shales . . about 200 



Basement beds, sandstone, and breccia . . , from 100 to 250 



Lower Sandstone or Basement Beds. The actual base 

 of the series is generally a bed of calcareous breccia, but sometimes 

 a hard pebbly quartz grit ; this rests on an eroded surface of 

 the Bunter sandstone (see p. 357), and marks a sudden change in 

 the physical conditions, though the break does not amount to an 



