This is a section of the bank and ditch known as Cwys yr Ychen Bannog, NPRN 303652. It runs for about 370 metres stretch running from a spring at SN72156179, crossing the ridge of Y Bryn and ending in a marshy saddle at SN72516167 where is disappears into the bog. The ditch, on the south side, is 1.5 metres wide at the top; the bank itself is 2 metres wide, 0.5 metres high. J. J. Hall, Trysor, 6th February 2013