THE 



ESSEX NATURALIST 



BEING THE 



Journal of tbc £06cy jficlt) Club, 



^(VOLUME XII.) 



GEOLOGICAL NOTES ON THE NEW RESER- 

 VOIRS IN THE VALLEY OF THE LEA, NEAR 

 WALTHAMSTOW, ESSEX. 



By T. V. HOLMES, F.G.S., F. Anthrop-Inst. ; Vice-President E.F.C. 

 [Received April 25th, 1901.] 



These reservoirs, the excavations for which have been in 

 progress for more than a year and are still proceeding, are in the 

 Valley of the Lea west of Walthamstow and east of Tottenham, 

 and are being executed for the East London Water Company 

 by Messrs. S. Pearson and Sons. The more northerly, which 

 will be known as the Banbury Reservoir, occupies the marsh 

 between Higham Hill and the outfall of the Ching ; the more 

 southerly is south west of Higham Hill and east of Stonebridge 

 Lock. The words " Mitchley Marsh" appear on the Ordnance 

 Map (6in. to the mile) towards its southern end. Two older 

 reservoirs, known as the Low and High Maynard, lie east or 

 south-east of this new " Lockwood " Reservoir. All are north 

 of the road connecting Tottenham Hale and Blackhorse Road 

 railway stations. (See Plan). 



Before touching upon the nature of the beds seen in the 

 reservoir excavations, it may be useful to say a few words on the 

 general geological structure of tlie locality. The oldest forma- 

 tion visible is the London Clay, which underlies the marshes in 

 the Lea Valley and appears in the higher ground on each side. 

 Patches of gravel and loam, fragments of old river deposits 

 formed when the existing streams, not having eroded their 



