By Professor T. Rupert Jones, F,R.S., F.G.S., 8fc. 133 



more above the Reading Beds still undisturbed below. In Kent, 

 Middlesex, and Hertfordshire the Woolwich-and-Reading Beds were 

 the more prolific source of these blocks. 



Doubtless many blocks were forcibly moved away from their 

 parent beds and knocked about as the strata were denuded at their 

 edges by encroaching waters, but where the stones lie flat over wide 

 areas, or have been arranged in an orderly manner in superficial 

 hollows with brick-earth made out of the beds themselves, doubtless 

 they were " quietly let down during the slow denudation and re- 

 moval of the softer material of the beds of which they once formed 

 a part." Whitaker, Geol. Mem., Explan. Sheet 7, p. 72. 



In the gravel on Crawley or Portisbury Hill, above Camberley, a 

 spur of the Frimley Ridges, very fresh Sarsens are met with. The 

 Upper Bagshot Sand has here been denuded and replaced with the 

 high-level ferruginous flint gravel ; and in this the Sarsens lie, their 

 mother-sand having been removed from above and around them, 

 but still almost in contact with their convex lower face. 



Sarsens are very often found in the patches and pockets of sand, 

 brick-earth, and gravel on the Chalk, 1 and usually are then much 

 eroded and worn. These materials are the remnants of Tertiary Beds 

 once lying, perhaps thick, on the Chalk, together with some of the 

 flint of the denuded Chalk itself. On Barbury Down (and probably 

 elsewhere) occasionally a green-coated flint, peculiar to the lowest 

 stratum of the Woolwich-and-Reading Beds, may be picked up, 

 showing that these beds contributed some of the alluvial spoil of 

 that region, and possibly, as far as they reached, some of the Sarsens. 



1 Near Wycombe, Nobles, Napple Common, Walter's Ash, Denman Hill, 

 Bryant's Bottom, Hampden Row, &c, also in the Marlborough Railway-cutting", 

 at Inkpen, and many other places. Sarsens are particularly abundant in the 

 gravel of the Kennet Valley, near Newbury. 



Dr. Joseph Stevens, in his papers " on Sarsens, Grey wethers, Druid Stones," 

 read before the Winchester and Brighton Natural History Societies in 1874 (see 

 the bibliographic list), after noting the distribution, origin, and structure of 

 these sandstone blocks, considers their drifting, or removal from the original 

 sands, to have been coeval with the formation of the Brick-earth on the high 

 Chalk tracts, which is inferred to have been deposited at the close of the Glacial 

 Period. Geolog. Record, vol. i., p. 35, and vol. h\, p. 37. 



