NEOLITHIC SITES IN UPPER VALLEY OF ESSEX CAM. 53 
THE VALLEY OF THE ESSEX CAM. 
The sites to be described are all situated in the drainage 
area of the Cam, and they are, with the single exception of 
Coploe Hill, within the County boundary. 
The Cam takes its origin in a series of field ditches around 
the villages of Elsenham and Henham. Elsenham is situated 
on the water parting of the Cam and the Stort. The stream 
therefore cuts back into the Chalk escarpment for a distance of 
about ten miles before it debouches upon the flat alluvial valley 
north of the Cambridge village of Ickleton. It has therefore 
the character of an obsequent stream and there is evidence that 
in glacial or pre-glacial times a gorge, now filled with glacial 
debris, existed through the Chalk Downs and may have drained 
much of the fenland area south into the Thames estuary, (i.) 
The head of the highest stream course is situated at a height of 
390 ft. O.D. and its level at the county boundary at Ickleton is 
approximately iooft. O.D. The real source is situated at 
Newport, about seven miles from this spot, and is at approxi¬ 
mately 200ft. O.D. From the highest point on the stream 
course running water only occurs in times of rain, but just south 
of the village of Newport permanent springs exist which main¬ 
tain a constant supply of water throughout the year. Above 
the 300ft. contour line water occurs in ponds and undrained 
Follows. On the east, secondary valleys enter the main valley 
at Newport from Debden, and north and south of Audley End 
Mansion where the Fulfen and Walden Slades enter the main 
stream. On the west, the Cam receives the drainage of the Arkes- 
den Valley at Newport, of the Elmdon Valley at Wenden, of a 
small valley from Strethall, and of two long valleys at Ickleton. 
All these secondary valleys are characterized by the fact that 
their drainage originates in field ditches on the clay-capped 
hill-tops and their channels are dry during the greater part 
of the year. Near their mouths permanent springs are found 
at approximately 200ft. O.D. 
The general elevation of the escarpment and its subsidiary 
ridges is between 300 and 400ft. O.D., but a height of about 
490ft. is reached near High Wood on the extreme west of the 
area. The slopes are gentle and rounded, decreasing in steep¬ 
ness towards the north. Below the spring heads a narrow 
