SllAFTESBURY MEETING. llX. 



Mr. Hudleston then spoke on 



The Geology of the District. 



The plateau on which the Club were standing consisted of the 

 Upper Greensand, an excessively porous formation about 150 

 feet thick in that district, with the Gault clay underlying it and 

 holding up the water which it contained. Thus about 25 feet 

 of the lowest beds of the Greensand was filled with water, while 

 the upper beds were dry. The Upper Greensand was the middle 

 member of the Cretaceous series here, the Chalk being the upper 

 member (he pointed to the Chalk hills in the distance) and the 

 Blue Gault at the bottom of the steep escarpment the lower 

 member of the series in that region. The Cretaceous series 

 rested upon the Jurassic found in the vale below, and as the dip 

 of the Jurassic beds was somewhat sharper than that of the 

 Cretaceous beds they came upon fresh Jurassic series as they 

 went eastward. For instance, here the Cretaceous beds rested 

 upon the Kimmeridge clay. Further on they rested on the 

 Portland sands, then on the Portland stone, then on the Purbeck 

 beds, and last of all on the Wealden. All of these ^vere 

 developed in the Vale of Wardour. Drawing attention to the 

 physiography of the region, he reminded them that the whole of 

 the beautiful landscape before them was the result of what 

 geologists called rain and rivers. It had been sculptured out 

 entirely by the atmospheric agents acting upon the land raised 

 up by certain architectonic forces. The Vale of Wardour was 

 remarkable in that respect, and was one of three systems of east 

 and west folding. This vale was an uprise or anticlinal axis, 

 and along that axis the excavation of the Vale of Wardour had 

 been developed. On the north end of the anticlinal the beds 

 dipped as much as 20 degrees, whereas on the south side they 

 dipped only about five degrees. There was also a permanent 

 easterly dip of all these beds. They were then at an elevation 

 of about 700 feet above sea-level. At Castle Ditches the 

 elevation was about 600 feet — still on the Upper Greensand — 



