510 ON A GEKEEAL SECTION OE THE BlGSHOT STEATA. 



and the conditions indicated by it and its position. The previous 

 speakers had overlooked the fact that the Lower Sands, when near 

 the surface, were only the dirty green sands of the deeper well- 

 sections, cleaned from carbonaceous matter by the action of oxygen- 

 ated water, delta- conditions characterizing both the Middle and 

 Lower series. The horizon of the pebble-beds at Bracknell was 

 very clear, the evidence of this being given in the paper. In the 

 section near Ash mentioned by Mr. Monckton the northward dip 

 of the Lower Bagshots corresponded with the northern dip of the 

 small anticlinal at Aldershot; and a comparison of the two sections 

 seemed to afford further proof of the pre-Bagshot erosion of the 

 London Clay. He regarded the whole evidence as pointing to the 

 partial formation of the present London-Clay syncline and to 

 considerable denudation before the deposition of the Bagshot beds. 



