All that remains of this fort is the oval shaped hedge and bank that surrounds a field. It position in the West Looe valley would have made it difficult to attack being on a steep sided promontry. Originally a small round fort at the north end, another circle was added to fill the current space. Eventually the Giants Hedge was built on the east side and this became the main defensive wall.
During the dark ages it was the site of a hermitage and Chapel for St Nunna, the mother of St David. An unspoilt well that bears her name is just to the north.
More detail about the well right next to the fort, which Mr Hamhead mentions in his fieldnotes. You may notice that the story is similar to that attached to various standing stones.
On the western side of the beautiful valley through which flows the Trelawny River, and near Hobb's Park, in the parish of Pelynt, Cornwall, is St. Nunn's or St. Ninnie's Well. Its position was, until very lately, to be discovered by the oak and bramble which grew upon its roof. It is entered by a doorway with a stone lintel, and overshadowed by an oak. [...] At the farther end of the floor is a round granite basin with a deeply moulded rim, and ornamented with a series of rings, each enclosing a cross or a ball. The water weeps into it from an opening at the back, and escapes again by a hole in the bottom. [...]
An old farmer (so runs the legend) once set his eyes upon the granite basin and coveted it, for it was no wrong in his eyes to convert the holy font to the base uses of a pigsty, and accordingly he drove his oxen and wain to the gateway above for the purpose of removing it. Taking his beasts to the entrance of the well, he essayed to drag the trough from its ancient bed. For a long time it resisted the efforts of the oxen, but at length they succeeded in starting it, and dragged it slowly up the hillside to where the wain was standing. Here, however it burst away from the chains which held it, and, rolling back again to the well, made a sharp turn and regained its old position, where it has remained ever since. Nor will anyone again attempt its removal, seeing that the farmer who was previously well-to-do in the world, never prospered from that day forward. Some people say, indeed, that retribution overtook him on the spot, the oxen falling dead, and the owner being struck lame and speechless.
[...] The people of the neighbourhood knew the well by the names St. Ninnie's, St. Nun's, and Piskies' Well. [...] In the basin of the well may be found a great number of pins, thrown in by those who have visited it out of curiosity, or to avail themselves of the virtues of its waters. A writer, anxious to know what meaning the peasantry attach to this strange custom, on asking a man at work near the spot, was told that it was done "to get the goodwill of the Piskies," who after the tribute of a pin not only ceased to mislead them, but rendered fortunate the operations of husbandry.
It has yet another name, St. Nonna's, on the OS map. From 'The legendary lore of the holy wells of England' by Robert Hope (1893), now available for your free perusal at the Open Library.