﻿338 THE EEV. E. C. SPICEE ON [^^o* I908, 



reproduces all the characteristic features of the Evenlode, its high 

 banks curving sharply round above a flat-bottomed valley upon 

 which a small stream meanders like a ' misfit * (see PI. XXXIX, 

 fig. 1). 



The spectre of erosion which appears to haunt almost every 

 valley upon the earth's surface must, I think, be banished from the 

 Great Oolite plateau. The valleys under consideration have no 

 single confirmatory mark of erosion. They swing to and fro, but 

 that is all. The existing plateau-slopes are not steep enough to 

 give sufficient erosive force to water, and there is not enough 

 existing water for the purpose if they were. In most of the 

 valleys there is no water at all. A deeply-eroded valley ends in an 

 alluvial fan, or in a cone of aggraded material, but these valleys 

 show no sign of ever having had such terminations : there are no 

 gravel- deposits, no gravel-terraces ; they melt into the main valley 

 and disappear. 



There is also no sign of the past existence of any surrounding 

 heights sufficiently great to have produced streams strong enough 

 to carve out the valleys by mechanical erosion. The whole region 

 appears to have been never anything but a gently-tilted plateau. 



The number and the varied direction of the valleys and their 

 absolute similarity taken together are also strongly against any 

 theory of mechanical erosion, for what conditions could be imagined 

 that could produce similar results in various directions crowded 

 together upon the same area? This type of valley, moreover, is 

 entirely confined to the limestone. The clay-valleys in the Oxford 

 area are wide and shallow, whether Oxfordian, Kimeridgian, or 

 Selbornian. The only valleys at all similar are those very short 

 ones (as upon Shotover and Cumnor) where sand and clay rest 

 upon Corallian limestone, or plateau-gravels upon Portland Eock. 



The idea that I venture to suggest occurred when noticing in 

 the Dorn Valley the course of a small waterway about 20 yards 

 long entering the stream almost at its level. This stream runs out 

 of a small hill for a few months only in every year. A small 

 cirque rises above the head of it, eating back into the hill. The 

 sides of the very short valley advancing towards the stream are 

 steep like those of the surrounding valleys. An underground 

 waterwheel some distance above it is thickly coated with stalactite. 

 The water contains, therefore, a considerable amount of carbonate 

 of lime in solution. The connexion of the cirque with the short 

 valley suggested that the limestone-rock was being removed in 

 solution, and that upon its removal the insoluble material sank 

 down nearly to the issuing water-level in such wise as to form a 

 £at floor. 



On climbing the bank and walking down-stream, a shallow, 

 winding, dry valley was seen stretching across the ploughed corn- 

 land and meandering into the distance upwards while sinking 

 downwards towards the Dorn. It occurred to me that, if under- 

 ground solution were the cause of the cirque, it might be the cause 



