ON THE LEA VALLEY. 3 



valleys to their present depth, were flowing at some higher level, 

 often cap the London Clay at various heights. The lowest and 

 most recent of these river-deposits are those forming the marshes 

 bordering the Lea, in which the new reservoirs are being 

 excavated. Other gravel patches, which may be seen here and 

 there a few miles from the reservoirs, usually at greater heights 

 than the highest of the deposits mentioned, being unjonnected 

 with any existing river system do not here concern us. 



In the immediate neighbourhood of the new reservoirs, a 

 good example of the fragment of an old river deposit may be 

 seen on the northern slope of Higham Hill, about 150 yards 

 south-east of Higham Hill Ferry, and the same distance from 

 the southern edge of the more northerly of the two new 

 reservoirs. West of the Lea, the high road between Tottenham 

 and Edmonton is on old river gravel of less age and elevation 

 than that of Higham Hill. And while no bare London Clay is 

 anywhere visible between the marshes of the Lea and the 

 slightly older and more elevated gravel of Tottenham and Ed- 

 monton, there is a distinct belt of London Clay between the 

 marsh in which Banbury Reservoir is being excavated, and the 

 gravel and loam capping the northern edge of Higham Hill. 



Another point of distinction between the g;ravel and loam of 

 Higham Hill, and of Walthamstow generally, and that of 

 Edmonton and Tottenham lies in the fact that the}' appear to 

 belong to two different rivers, the first-named to the Thames, 

 the latter to the Lea. At the present day we naturally consider 

 ourselves in the valley of the Lea four or five miles south of 

 Higham Hill. But examination of the Geological Survey Map 

 of the district showing the distribution of the river-deposits 

 makes it evident that the Thames, a,t one time, both above and 

 below London, took its course some miles north of its present 

 channel. And that the gravel of Stamford Hill, Higham Hill, 

 and Walthamstow was formed in all probability by the Thames, 

 when flowing in ancient times in a more northerh- and a more 

 elevated channel than it now does. 



Before descending from Higham Hill to the Marshes in 

 which the reservoirs are being excavated it may be well to note 

 the nature of the more ancient river-dep;)sits capping the hill. 

 They consist of gravel covered more or less irregularly by loam. 



