Holmesdale Natural History Club. 57 



is a source of never-failing enjoyment. I may state at the outset that in 

 my remarks on the rivers of Surrey I omit altogether Father Thames, not- 

 withstanding that river forms the northern boundary of the whole county, 

 and is the most important of its streams. I treat of those rivers only which 

 flow through the county, or have their rise within its boundaries, and flow 

 into the Thames. But as a preliminary step, I must yet go bey end the 

 boundaries of the county, in order to present to notice the eneral 

 geological and topographical features of the district, upon the character of 

 which the peculiarites of the several rivers of Surrey depend. We notice 

 in Eeigate and its neighbourhood the vast wall of chalk facing the south, 

 which in a very marked manner presents itself to our attention. This wall 

 of chalk is the steep side of the range of hills known as the North Downi. 

 It is not confined to Surrey, but extends continuously in a N.E. direction to 

 Chatham, in Kent, and thence continues in a S.E. direction to Folkestone 

 and Dover, forming between those two towns the towering sea cliffs from 

 400 to 500 feet high, part of which is the well-known Skakespeare'a Cliff. 

 From Eeigate westward the same wall of chalk extends to Guildford ; from 

 that point it turns to the S.W., and leaving Surrey enters Hampshire, 

 running south, the steep face of the hills in that locality looking eastward, 

 until the range strikes Sussex. It then again turns east, having the steep 

 face of the hills toward the north, that is facing towards the Reigate Hills. 

 These hills, here named the South Downs, terminate in the bold cliffs at 

 Beachy Head. The summits of the northern range of this wall of chalk 

 have an average elevation of from 300 to 400 feet above the valley which 

 lies between the chalk range and the parallel range of the greensand, and 

 an elevation of 600 to 800 feet above the level of the sea. In the northern 

 range of chalk, which we may call o%i,r range, the hills are in five places cut 

 down to the level of the greensand valley, viz :— Near Ashf ord, in Kent, by 

 the River Stour ; at Rochester, by the Medway ; near Sevenoaks, by the 

 Darent ; at Box Hill, by the Mole ; at Guildford, by the Wey. The two last 

 named places are within the limits of our subject this evening. 



There are three classes of rivers in Surrey. (1.) Those which have their 

 sources south of the chalk range, and find their way to the Thames through 

 deep depressions in the chalk, like those just referred to, of which the rivers 

 Mole and Wey are instances. (2.) Those rivers which have their sources on 

 the northern slope of the chalk formation, of which the Wandle and the Hog's 

 Mill river are examples. And (3.) Those which have their sources in the Bag- 

 shot sands. In each case the ultimate course of all the rivers, except those 

 having their sources in the Bagshot sands, is northerly ; those rising in the 

 Bagshot sands have a course eastward. All fall into the Thames. We will, if 

 you please, commence on the eastern side of the county. There are several 

 small brooks which I will not trouble you with, as the Eflfra at Brixton, 

 which now forms a sewer. The first river of note is the Wandle. This has 

 its sources near Croydon and Beddington in the gravel which overlies the 

 chalk; and derives its water chiefly from springs which are the 

 outflow from the chalk region. Its waters are very clear. It receives very 



