538 JR. H. Chandler— Dry Chalk Valley Features. 



must have extended not less than some 2000 or 3000 years further 

 back still — that is, to some 8000 or 9000 years from now. And 

 Professor Flinders Petrie informs me that neither in the remains 

 of the historic nor of the prehistoric period can he find any evidence 

 of a climate that was appreciably different from that of Egypt at 

 the present time. If, then, the estimates of Post-Glacial time that 

 are under consideration can be accepted, we must suppose that large, 

 civilized, agricultural populations lived and moved and had their 

 being, built the monuments and left the legible inscriptions that have 

 come down to us to-day, utterly unaffected, during a period of some 

 3000 or 4000 years, by the gigantic changes of climate that were 

 in progress no further away than the northern shores of the 

 Mediterranean ! 



During the past thirty or forty years we have been told so many 

 times that this or that consideration, generally a physical one, imposed 

 an absolute limit on some piece of geological chronology, that geologists 

 may well pause before insisting that archaeology can impose a limit 

 of another kind. The history of speculation upon geological time 

 may well serve to sober the boldest of calculators. ^Nevertheless, 

 there does seem reason to think that the records so wonderfully 

 brought to light from Ancient Egypt may aid us in the solution 

 of a vexed question in geology, even as they are now doing with 

 regard to vexed questions in other subjects of research. 



IV. — On some Dry Chalx Valley Eeatuees. 

 By R. H. Chandler. 

 rpHE existence of a ' wind gap ' or ' pass' at the head of a dry dij) 

 JL valley clearly points to the former extension of that valley 

 beyond the present escarpment ; and the depth of the gap is a measure 

 of the size of the valley before being beheaded by the recession of the 

 escarpment. Thus the gap at Merstham is about 300 feet deep, and 

 the valley would probably have continued south some miles on to the 

 Wealden uplands ; the floor of this valley falls regularly north, and 

 presents all the features due to a stream flowing in that direction 

 previous to the formation of the Gault strike valley. As an instance 

 of a less developed beheaded valley, the Maplescombe valley, which 

 joins the Darent valley on the right bank at Parningham, may be 

 instanced. The Maplescombe valley has a ' wind gap ' of possibly 

 100 feet deep, and so its former southward extension would not have 

 continued into the Wealden area as far as the Merstham valley ; 

 moreover, the floor does not slope regularly to the Darent, but is 

 steepest at the head, the distance between each contour-line increasing 

 as one descends the valley, viz. — 



600 to 500 in 1700 feet, or fall of 1 in 17. 



500 to 400 in 3000 feet, or fall of 1 in 30, 



400 to 300 in 5300 feet, or fall of 1 in 53. 



300 to 200 in 7200 feet, or fall of 1 in 72. 

 The present valley floor, particularly the upper part, is evidently not 

 the one down which a stream from the Weald would have flowed, 

 for at the above noted rate of increased slope the valley would ' run 



