290 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Juiie 1, 



grounds, which I have above described under the name of Dartford 

 gravel. 



In the cuttings on the old Rochester road, between Greenhithe 

 and Gravesend, there are only slight remains of the Dartford gravel, 

 either as filling pipes in the chalk, or as forming a thin film between 

 the chalk and the warp-drift. 



Between Gravesend and Gadshill there is nothing to be seen in the 

 road-sections except a rather deep warp-drift of loam and angular 

 flints, resting in some places on the chalk, in others on the Thanet 

 Sand. But on the summit of Gadshill, there are again slight traces 

 of the ferruginous gravel. At the eastern base of that hill, we come 

 on the warp-drift again ; and between the solid and the reconstructed 

 chalk, I found a few eocene pebbles and fragments of ferruginous 

 sandstone, the reconstructed chalk being covered with several feet 

 of loam with flints. This passes into the same kind of deposit, of 

 greater depth, which, at lower levels, within the valley of the Medway, 

 covers beds of brick-earth, graduating horizontally into gravel and 

 masses of chalk rubble. These will be described in a future paper, 

 in which I shall show that they rest on deposits containing land and 

 freshwater shells. 



In tracing the Dartford gravel westwards, eocene pebbles are found 

 to increase in quantity, between the Darent and the Cray ; west of 

 the Cray, they prevail almost to the exclusion of other materials. 

 The outcrop of one of the pebble beds of that period ranges near 

 Bexley Heath, where the superficial deposits consist wholly of those 

 pebbles, re-arranged in a base of yellow sand and loam, of a different 

 colour from that of the original matrix. 



Shooter s Hill Gravel. — On the summit of Shooter's Hill, and at 

 an elevation therefore of nearly 446 feet, there is a bed of .gravel in 

 which partially worn flints again make their appearance (see Plate 

 XIII.). Many of the rolled pebbles associated with them have been 

 derived probably from some eocene bed ; but there are others which 

 appear to have been reduced to that state during the formation of 

 this gravel, because flints occur in it in different stages of attrition, 

 from the least to the most rolled. 



Rochester Gravel. — The Rochester gravel occurs near Ring's 

 Farm, on the right bank of the Medway, about two miles above Ro- 

 chester, at an elevation which, I believe, is somewhat less than that 

 of the Dartford gravel. 



The surface of the fields under which it occurs is very thickly 

 strewn with sharply fractured flints. A gravel-pit which was open 

 in 1852, but which is now levelled and ploughed over, showed the 

 gravel to be about 15 feet deep. The upper part consisted of a fer- 

 ruginous clayey loam with angular flints, very similar to that which 

 covers the summits of the higher chalk hills, and bears the provin- 

 cial name of "cledge." It passes occasionally into masses of an- 

 gular flint-gravel in a clayey matrix. In the lower portion of the 

 deposit white flints prevailed, accompanied by a few fragments of 

 chalk, and some unabraded fragments of concretionary chert, contain- 

 ing or passing into flint, and derived, I believe, from part of the green- 



