:214 PEOF. J. E. MAKE ON THE [vol. lxXV, 



shown in many ways. The sides are too steep for ordinary 

 subaerial channels in loose material ; the deposits on each side 

 hend down towards the channels ; and the material of the sides 

 is dragged into the channels, forming selvages. Again, many 

 incipient channels occur in every stage from slight settling of 

 the marginal deposits along a plane of weakness to the fully-formed 

 channel. In one case a channel does not go to the surface, as a 

 ferruginous gravel at the base of the uneven series has resisted the 

 foundering ; this channel was cut into the underlying Grault to a 

 depth of 2 feet, and the gravels let down into the Grault, and a 

 stream of Avater was found flowing at the bottom. Two of these 

 channels were far apart some years ago, but approached each other 

 as the pit-face was cut back. They coalesced as digging proceeded, 

 and have now diverged once more, so that they crossed at the point 

 of coalescence. 



As regards the nature of the pebbles in the deposits one need say 

 little, as it is described in the Geological Survey Memoir. They 

 are chiefly flint, usually in subangular pebbles, no doubt broken by 

 water-action and afterwards waterworn in different degrees. They 

 have usually milky-blue surfaces. I mention this, as the surfaces 

 of the implements are often of a very different character, and one 

 which shows that many of them lay on the surface and were exposed 

 to weathering action before they were embedded in the deposits. 



The boulders are those of rocks derived from the Boulder- Clay 

 of the area. Their characters have been described in a paper by 

 Mr. R. H. Rastall & Mr. J. Romanes. 1 Among them I have found 

 a few pebbles of Red Chalk, and several are identified with a rock 

 -occurring in the Corallian beds of Yorkshire. There are frequent 

 boulders of rhomb-porphyry, usually of small size, but one which 

 I obtained from the South Pit measures 12 X 11 X 7 inches : it is 

 now in the Sedgwick Museum. Porosphcerce are occasionally 

 found. 



It is quite clear that the lower evenly-bedded and the unevenly- 

 bedded series of deposits were laid down by water ; but the origin 

 of the uppermost loams requires elucidation, for the included 

 gravels may be due to inconstant wash on slopes. 



The upper evenly-bedded deposits resemble on the whole the 

 lower deposits, but are much thinner. I do not consider that the 

 time that elapsed between the lower evenly-bedded and the un- 

 evenly-bedded deposits was very long ; but the junction between 

 the latter and the upper evenly-bedded sediments is of a nature 

 Avhich indicates that important changes occurred between the for- 

 mation of the two series, and this must have taken some time. 



We may pass now to the consideration of the fossils, including 

 the implements. Apart from the latter, fossils unfortunately are 

 extraordinarily rare. Implements are relatively abundant, and 

 I have collected with my own hands a large series from the 



1 Q. J. G. S. vol. lxv (1909) p. 246. 



