TBUIfZS IK- QUATERNARY SANDS AT READING. 299 



force of the aqueous agency- is further seen in the steep incline on 

 which the beds are deposited ; deposition in comparatively still 

 water would have produced horizontality in the strata. 



(b) This stratum consists of a bed of sand 9 feet thick where it extends up- 

 wards to the gravels with no intervening clays. Its base is not seen in 

 this north face ; for water is reached at the level drawn on the section. It 

 is derived mainly from the destruction of the " Buff Sands " of the 

 Woolwich and Eeading series. The sands are generally white, but often 

 yellow or orange, from ferruginous staining, especially near the in- 

 cluded tree-trunks, one of which often discolors the sand for a few feet 

 round it. The sand-grains immediately surrounding the trunks are 

 often bound together into an extremely hard conglomerate by a ferrugi- 

 nous cement ; and the whole is generally firmly adherent to the trunk 

 itself. Small pebbles occasionally occur in the sands. The whole bed 

 gives one the impression that it was subject to long-continued but gentle 

 fiuviatile action, as compared with the clays above. The condition of 

 the bones found in this bed is in favour of this view ; for they are very 

 waterworn and yet unbroken, while those of the gravel above are often 

 broken sharply but their surfaces ai-e far more perfect. Curiously the 

 shifting currents and eddies of fluviatile deposition have produced a 

 result strikingly like the original " Buff Sands" from which these beds 

 were derived. The general irregular arrangement of the bedding only 

 is given over the main part of the section (although the imbedded 

 plant-remains (x) exposed in the face are accurately placed); but to the 

 west and below, a series of beds showing the oblique laminations very 

 distinctly are drawn carefully to scale. 



The beds are lettered in the order of their deposition. 



(a). The first deposited, and forming the axis of the group, is 

 horizontal, and was therefore probably thrown down in compara- 

 tively still water. The laminge are of coarse yellow and white sand, 

 becoming deeply orange from ferruginous colouring in some parts. 

 Small pebbles are common ; and there are thin laminated clay-seams 

 in the lower part and to the west — additional proofs of the gentle 

 aqueous agency. 



(b). Then followed swifter currents from the east and directed 

 downwards, cutting away the west part of (a), so that its laminag 

 terminate abruptly in a slope of 45°. Against this, as the current 

 became gentler, the bed (h) was deposited of fine white sand below, 

 coarse above. 



(c) and (d). Then currents from the west cut away (6) and (a) 

 nearly horizontally, and (c) and (d) were deposited on them. 

 These are of very fine white sand. There is an unconform ability 

 between (c) and (d) to the west, caused by some change in the 

 current after (c) was thrown down. East, they form one bed. 



(e). After this, more rapid currents from the west removed the 

 east part of (d) and {a) ; and on the steep slope thus formed the 

 fine white sand forming the bed (e) was deposited. In its lower 

 part a few angular lumps of bluish clay occur, evidences of the 

 rapidity of the currents, probably derived from the destruction of 

 the " Leaf-beds." 



(/). Finally gentler currents from the west planed off the tops of 

 (h) (d) and {e), and on them deposited the laminated sandy clay 



x2 



