Vol. 51.] GREENLAND OF EAST SURREY. 109 



of the drift has been worked into the loose sands, channels of it 

 apparently passing right into them. The drift consists entirely, so 

 far as I have observed, of Lower Greensand material ; towards the 

 bottom it is mainly rough angular chert, often in large pieces. There 

 are also lenticular beds of grit, chiefly Bargate debris. One of the 

 specimens exhibited is a block of chert which has Bargate debris, 

 with the cast of a bivalve, adhering to it. In some places sandy 

 brick-earth overlies the rougher drift, there are lenticular beds of 

 sand throughout, and generally the drift may be said to be coarser 

 and rougher in the lower layers. Farther south, in Chart Lane, 

 below the junction of the New Road, drift with chert is seen, over 

 the sandy beds ; this, although 12 feet thick in places, appears to be, 

 properly speaking, the ' run of the hill ' ; it consists of sandy brick- 

 earth with scattered fragments of angular chert. A similar but 

 smaller 'run' appears to pass down the northern slope of the hill also. 



The drift in situ lies at the highest part of the escarpment ; 

 Glory Wood is above 400 O.D., the section in Chart Lane about 

 370 O.D. A similar drift, only less rough and with the Bargate 

 pebbles more generally distributed, is seen in Punchbowl Lane at 

 306 O.D., at the junction of the bridle-path to Park Farm. It lies on 

 an uneven surface of the buff sands, 100 yards to the south of, and 

 6 feet below the level of, the doubtful bed of chert already referred 

 to. This gravel has all the appearance of having been, like the 

 higher one, deposited by runniug water, and it is clear that, since 

 both beds must belong to the past history of the Mole, the 

 material of which they are composed must have been brought from 

 the country to the south, and that therefore the chert-beds and 

 overlying Bargates formerly existed there. 



The evidence does not end here, however, for the surface of the 

 country to the south is strewed with chert-debris, and the alluvium 

 of the brooks flowing thence into the Mole is full of it. 



Taking the waterways first, chert in plenty may be found in the 

 beds of Bent's Brook and the Black Brook ; in Tanner's Brook 

 at Brockham the pebbles are chiefly from the Wealden Beds, 

 but large, partly sunken blocks of chert may also be seen. Iu 

 the Mole under Box Hill, that is, east of the gap in the Chalk 

 escarpment, the chert occurs within the Yale of Holmesdale ; 

 it also may be seen, associated with Bargate debris, in a small 

 exposure of high-level river-drift, over the Folkestone Sands on the 

 Reigate Road, a little east of Punchbowl Lane. This small section 

 is capped by hill-wash, but the lower beds have clearly been deposited 

 by a river. 



• The surface of the Weald Clay at Holmwood Common is strewed 

 with chert-debris, and it is interesting to notice that the massive 

 chert-beds have chiefly supplied the pebbles here, while those 

 to the north are from the upper division. Chert-pebbles may be 

 seen in situ in the soil over the clay, in a small section at the side of 

 the road leading to the brickfield, west of Brookmeadow on Holm- 

 wood Common, while they accumulate and are gathered into heaps 

 on the cultivated lands to the west. 



Towards the foot of the escarpment of Leith Hill there is no 

 Q. J. G. S. No. 202. it 



