Description from GGAT HER :
An unscheduled promontory fort lying just outside NT property on sloping ground of Oxwich Point. The whole area is thickly covered with trees and undergrowth obscuring the remains, the exact boundaries of the fort are uncertain.
Two lines of defence protect an inner area of just 0.2ha. At the eastern end the outer defence consists of the low remains of a rubble bank above a steep natural scarp. To the SE the bank increases in size with an external ditch and a slight outer bank. Along the southern side of the fort the bank loses the external ditch and becomes a counterscarp to the inner defences, dying away on the SW side. At this point the earth built inner bank is nearly 2m high overall with a ditch in-between the banks around the southern corner. At the western end the bank increases to c3m high accompanied by a partly rock cut ditch. The bank dies away to the east and north, with the external ditch being used as a hollow way to the north. The entrance is visible in the outer bank where it turns inwards to form a parallel sided passage c9m long. The entrance through the inner rampart was probably a gap between the western end of the rampart and the cliff edge. At this point is a possible hut site, no other hut sites have been identified. (01)

Lies between 60-75m OD, above a hillside falling steeply to Oxwich Bay. The greater part of the enclosed land slopes down towards the NE 30m after the W angle a line of cliffs runs NE. The outer defence seems to have enclosed 0.6ha, the inner 0.2ha, but neither terminate on a natural obstacle and the boundaries of the fort to the N are uncertain.
The outer rampart appears first at its E end, increasing in size and rounding the S corner, as the stone in the bank becomes earth further to the W. On the SE this outer rampart is accompanied by a slight outer bank with an outer ditch, but this ditch becomes a counterscarp bank, and diverges from the main rampart in the SW.
The inner rampart forms a quadrant about 60m long which dies away at its E end, and has a rock cut ditch on the W end.
The entrance through the outer rampart seems to have been where the rampart is not crossed by a modern wall. The banks turn in to form a parallel-sided passage 9m long. The inner rampart was then probably accessed via the W end of the rampart and the end of the cliff.

A small oval cut hollow just below the cliff gives the impression of a hut, perhaps a guard chamber, but this cannot be ascertained further without excavation. (Wiggins and Evans 2005)

Sources :
Wiggins, H and Evans, E , 2005 , Prehistoric defended enclosures in Glamorgan with recommendations for fieldwork
01. P Poucher (2003-04) The National Trust Archaeological Survey: The South Gower Coastal Properties, Mewslade - Port Eynon, Pilton Green, Pilton Cross and Oxwich