304 E. B. POTJLTON ON MAMMALIAN EEMAINS AND TKEE- 



The whole series 1-5 probably corresponds to the Leaf-beds, with 

 a little local variation. Beneath the bed D, and covering the 

 Chalk, was a flat flint so traversed by vertical fissures that it was 

 easily removed in cubical blocks. It extended over the entire bottom 

 of the pit, and was therefore, as far as we saw it, 5 feet x 2 feet in 

 area, and about 6 inches thick. At the sides it was continuous 

 under the green-coated pebbles ; and thus we could not find its true 

 size. But while the undisturbed Tertiary beds thus underlie the 

 sands and clays exposed in the east face, the latter are reconstructed 

 quaternary beds, although their lowest part, just above the Leaf- 

 beds may be undisturbed and Tertiary, as shown in fig. 2, at the 

 line A to B. In nearly the whole height of this eastern exposure 

 of sand (about 8 to 10 feet), and along its whole length (151 feet), 

 irregular bands of clay-fragments occur, some still angular and re- 

 taining all the appearance they presented when the river- currents 

 detached them from the unaltered Tertiary beds higher up the slope 

 and transported them to this spot. Above the sand in the east face, 

 as in the north, the reconstructed mottled clays intervene in 

 patches between the sand and gravel. These clays are largely in- 

 tersected by bands of gravel, and contain scattered pebbles. There 

 is none of the lamination observed in the north face. Tracing these 

 reconstructed beds of the east face southward, towards the series 

 from which they were derived, they disappear beneath a vast pile of 

 rubbish ; and no indication of the transition is afforded. Jfeverthe- 

 less our pit at the base of this east cliff proved that the lower beds 

 of the Tertiary series are continued unaltered under these derived 

 strata ; and therefore the transitional line was then reached, as shown 

 in fig. 2. The west face, shorter but well exposed (83 feet 6 inches 

 long), is also reconstructed as far as it can be seen ; and its south 

 end affords no hint of the transition. 



In the south-west corner of the pit, the sands have been exposed 

 far south of the extreme southward extension of the west face of 

 sand (for the gravel is first worked independently, and cleared out 

 over a much greater area than the sand) ; and here too the beds are 

 reconstructed. Therefore the transitional line cannot be looked 

 for anywhere along the westward, north, and south limits of the 

 pit. 



On the other hand, further east, at the base of the former south 

 face (now a slope of turf), the men worked a bed of homogeneous 

 clay for some little time for brick-making ; and in the sands below 

 they found no tree-trunks or bones, and there was no evidence of 

 disturbance. The unfossiliferous character of the clay and the 

 oblique lamination of the sands were distinct and characteristic. 

 This south point is 276 feet from the north face. In this distance, 

 therefore, to the south, are the unaltered mottled clays and buff 

 sands of the Woolwich and Heading series, while to the north are 

 reconstructed beds of the elements of these strata intermixed with 

 the remains of a more recent period. 



Somewhere south of the present exposure of the east face is the 

 line of junction, which may have been in the form of a low cliff or 



