Monument record RBY 002 - Black Ditches, Risby Poor's Heath

Black Ditches, Cavenham. Scheduled Monument.
Linear earthwork (continuation of CAM 001), runs NNW-SSE.
1981: Ditch on W side filled in, slight indication of second ditch. The section S of the old chalk pit at TL 7750 6810 is largely destroyed, firstly by the pit and the road and then by ploughing. At the pit the ditch is 6.50m wide, depth approximately 1. 5m, the bank is 6. 5m wide and approximately 1. 75m high. The bank is composed largely of chalk rubble and flint. Extends S of scheduled area to TL 7768 6733 (S1). From TL 7748 6846 to TL 7750 6810 is grassed & flanked by arable land. Earthwork is invisible from TL 7750 6810 to approximately TL 7752 6800, to S... it is flattened but shows as a band of chalk in plough soil (S1)(S2).
N from summit of Twenty Acre Hill (TL 777 669) the line can be seen as a cropmark (S3)(actually only shown clearly as cropmark as far as TL 7759 6760 on AP (S6) cited by OS) of the earthwork that was extant circa 1900 (S3)(R1). Not marked on 1839 Tithe Map (S4) or shown S of TL 7759 6768 on OS 25 inch map for 1904 (S5). `An old quarry interrupts the line at TL 775 680 and a section of the bank and ditch can be seen in the N face. It measures 12.7m overall, the ditch bottom is 1.3m below ground level and the bank now 1.4m above ground level (see photo)' (S3).
Still shown as earthwork on 1958 map although on slightly different alignment to that further N (S8).
Mollusc samples were taken in 1980 from the edge of the bank at the old chalk pit- for report see Parish file.
OS AP shows linear feature/ditch running S from TL 7768 6727 to railway line at TL 7794 6596 (S7) - ?possible continuation of Black Ditches.