326 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



with unrolled chalk-flints imbedded in a brown and ferruginous clay. 

 To find similar fossiliferous blocks in situ, I re-examined the district 

 between this ridge and the Thames, but without success. I found, 

 however, at another chalk-pit between Lenham Hill and Harriets- 

 ham Hill, and distant seven-eighths of a mile W.N.W. from the 

 Lenham pit, some larger sand- and gravel-pipes, in which the more 

 defined structure led me to conclude that the sand- and iron-stone 

 of these pipes were not portions of drift, but were part of a de- 

 posit which once spread in regular beds over these hills, and a por- 

 tion of which had been let down as it were into these pipes, by the 

 gradual dissolution of the chalk at these spots, in the way I have 

 described in a former paper*. 



When a subsequent denudation removed the mass of the deposit from 

 that area, these fragmentary portions of the sands and ironstones 

 were protected by their position in the chalk, and remain as evidence 

 of its former wider extension. The Harrietsham pit shows the fol- 

 lowing interesting section : — 



Fig. 3. — Section on the Hill above Harrietsham, Kent, 

 abode edcba a b a a bed e f e deba 



x7* I ■»[ \ r^v 7 







X ' r Km ' 







Talus. 



f, e, Fine light-red and yellow sands, in parts very argillaceous. 

 d-b, Greenish sand, more or less argillaceous, with a subordinate bed or seam of 

 ironstone concretions (e). In places c reposes directly on a. 



a, Unrolled chalk-flints in brown and black clay. m, Chalk. 



I found only a few traces of fossils f in this pit, except some 

 doubtful vegetable or spongiform casts on the surface of the iron- 

 stone, of the size of fingers, ramified and entirely covering some 

 blocks. Flint-pebbles and a few very small quartz-pebbles occur in the 

 beds b-d, and are often encased in the ironstone, which also some- 

 times contains unrolled flints, as in bed a. Now, as these pipes are 

 cylindrical, and as each core of sand is symmetrical, with its several 

 layers following a like order of succession, and retaining a nearly uni- 

 form thickness ; and further, as the ironstone-band holds in each pipe 

 the same relative position, its separate fragments pitching downwards 

 with the curve assumed by the sand, it is to be inferred that these 

 are let-down portions of strata, of which the original structure was 

 horizontal and formed as in fig. 4. 



* Quart. Journ. Geol. Soc. vol. xi. p. 64. 



f The cast of a Cardium has since been found in the ironstone here. 



