42 



ME. H. W. MOl^CKTON ON THE GRAVELS SOUTH OF 



shows the Southern Drift, 6 feet thick, resting on Upper Bagshot 

 Sand. At 360 feet above O.D. there is a small patch of gravel 

 probably washed down from above at a very recent period. At 

 300 feet above O.D. there is rather a larger patch, and to the north 

 of the line of section and not shown in it is a gravel-capped hill, 

 300 to 320 feet above O.D., forming a minor ridge. It is at the foot 

 of White Hill, close to Polly Cottage, and is not mapped. The 

 gravel is 8 feet or more thick, and of the same character as the 



Pig. 3. — Section from Chohham Ridges to the Hale Bourne, 

 near Chohham. 



Horizontal scale: 1 inch=l mile. Vertical scale: 1 inch =440 feet. 



[The figiires indicate levels above O.D.] 

 For symbols, see fig. 1, p. 31. 



Southern Drift. I noticed two sarsen-stones in it, one 2 feet long 

 with 2 feet of gravel below, and 5 feet above it the other, 1| feet 

 long, only 2 feet from the surface. Both were tilted towards 

 Chobham Eidges. I look upon this as merely a gravel derived 

 from the Southern Drift which caps the Ridges. Lower down there 

 is the large patch of gravel, 200 to 224 feet above O.D., shown on 

 the Geological Survey map and in the diagram (fig. 3). The section, 

 just one mile west of the sign-post at the top of Chobham Ridges, 

 is as follows : — 



Peaty soil, 9 to 13 inches. 



Yellow and greenish sand, no doubt washed down from the Upper Bag- 

 shot Beds, 14 to 34 inches. 

 G-ravel, 18 to 25 inches. 



In the gravel are many sarsen-stones, bits of ironstone from the 

 Southern Drift, and a number of ferruginous concretions, some of 

 which are casts of univalve and bivalve shells from the Upper 

 Bagshot Beds. 



A little farther east there is a low plateau or collection of mound- 

 like hills 190 to 207 feet above O.D., called ]S"ew England Hill on 

 the Geological Survey map, Sheet YIII. These hills are capped 

 with gravel, and a section is seen in the sandpit by the side of the 



