Dundon Hill as it appears on the 1850 OS map.
There is a plan and short description in volume 2 of the Victoria County History for Somerset (pages 490-1).
Ian Burrow's Hillfort and Hill-top Settlement in Somerset in the First to Eighth Centuries has a more recent (but less detailed) description at p 214.
It's about 4.8 ha in area and univallate. No excavations seem to have been carried out though before the First World War flint and pottery scatters were found there.
Scheduled Monuments OBJECTID 43789 Reference SO22076 Name COMPTON DUNDON HILLFORT WITH DUNDON BEACON, EAST OF DUNDON Suffix OBJECTID 43789