122 MR. T. 1EIGHT0N OS THE LOWER [May 1 89 5, 



have all shown that the Bargate Beds overlie chert-beds in the 

 south, and sands in the north, a condition of things which agrees 

 with what is now claimed to have formerly existed here. In the 

 Leith Hill area the less littoral beds run up, as seen at Coast Hill, 

 to the parallel of the sandy area, to the east and west ; there is no 

 difficulty in accounting for this when the conditions of a marine 

 estuary are considered; it only shows that a ' deep ' formerly existed 

 there. 



It is impossible now to more than glance at the most important 

 of the many interesting points brought out by the table appended 

 to this paper of sections from the country to the east. I have 

 already pointed out that the Bargate Beds at Abinger are in- 

 separable from the similar bed at the base of the Eolkestones into 

 which there is a complete passage there. 1 The Pebble-beds at the 

 base of the Folkestones have been traced in this paper through 

 the Dorking country to Ileigate, where a thin bed of chert capped 

 by thin Fuller's Earth alone separates them from the ironsands. 

 The horizon of the two exposures of Pebble-beds above the top of 

 the Atherfield Clay further approximates closely, east and west of 

 the Mole Valley- — 160 to 170 feet at Punchbowl Lane and 160 at 

 Beigate. The exposures of Pebble-beds at Beigate, Bedhill, Nuf- 

 field, and Blechingley not only agree lithologically, but are in each 

 section seen to be overlain by sandy cherts followed by Puller's 

 Earth. It is difficult to imagine what evidence could be required 

 in such a set of beds to establish an horizon more perfectly. At 

 Tilburstow Hill the Pebble-beds have almost thinned out; the 

 pebbles generally decrease in size eastward. The overlying cherts, 

 on the contrary, increase in importance to the east, on this horizon, 

 until at Tilburstow Hill we find 55 feet of them. 



Whatever ma) - be the origin of the Fuller's Earth, it must certainly 

 have been formed in quiet waters ; but, as it overlies the less 

 littoral beds of this country, the conditions for the formation of 

 suitable lagoons can be easily imagined in a marine estuary such as 

 is here described. The ironsands of Local Group 4 are seen every- 

 where at the base of the series where that horizon is exposed, 

 and the so-called ' Hythe Beds' appear to die out within them 

 east of this area. It is noticeable that, some way above the horizon 

 of the probable Hythe Beds at Nutfield, a thin bed of chert occurs 

 in clayey sands. It is almost too much to say that this is the 

 representative of the Leith Hill horizon (Local Group 2), since, 

 wherever conditions were favourable, sponges may have grown, but 

 the horizon of its occurrence in clayey sands here exhibits a striking 

 parallel to what occurs in Deepdene Park, near Dorking. The 

 horizon of the Dorking clayey sands is suggested, to the east, by 

 somewhat similar beds at many places, and these may mark the 

 northern margin of the deeper water of that period. At Dorking 

 the beds of Local Group 3 doubtless mark the margin of the still 

 less littoral beds of the southern end of Leith Hill. The sandy 

 limestones and associated beds above and between the Fuller's Earth 



1 Proc. Geo!. Assoc. toI. xiii. (1893) p. 166 ; Quart. Jo urn. Geol. Soc. iol. 1. 

 (1894) p. 729. 



