Geology. 209 



^ . , ^ These four waters, with their numerous brook- 



Drainage of the 



district and lets and feeders, constitute the main drainage 

 general configu- of the district before their junction above 



ration. 



Bath. Anyone standing on the spur of 

 Hampton Down, near the present rifle butts, can trace the 

 course of these streams winding through their wooded 

 and picturesque channels, ultimately combining to form 

 the Bath basin widening towards the S.W. Here the 

 geologist has before him the key to unlock the pecu- 

 liar physical characteristics of the neighbourhood. On 

 either side, as he looks around him, he is struck with 

 the uniform level of the ground; his eye ranges over an 

 extensive plateau, bounded on the eastern horizon by the 

 Chalk downs of Wiltshire ; looking in another direction 

 northwards, across the valley to Lansdown and Bannerdown, 

 he notices the same table land extending as far as his eye 

 can reach, till it is lost in the sky line ; here and there 

 certainly an isolated round-topped hill breaks the view, and 

 seems apparently unconnected with the adjoining heights, 

 but this is only an ocular deception, and closer inspection 

 shows that it was originally one and the same portion of this 

 table land, but in later times cut out of and separated froih 

 the main mass. Turning southwards, he sees a somewhat 

 more rolling country, where this uniformity has been inter- 

 rupted, the general level being affected by the underground 

 irregularities and disturbances of the rocks, especially notice- 

 able in the vicinity of the Mendip hills. What then does he 

 gather from this panoramic view ? this surely, that he is 

 standing on the edge of a vast plain of marine denudation, 

 and looking down into the valleys which have subsequently 

 been worn down by subaerial agencies. The hills around the 

 city and out of which the Bath basin has been carved, form 



IS 



