It's about 100 feet in diameter, with what appear to be standing stones on top of the bank, in places, which is highest at the northern quarter, and seemingly constructed of rocks, which appear on the surface in this quarter.
When you visit it, you are struck more by its henge-like appearance than by any hut-circles, and the "standing stones" certainly seem too coincidental to be true. Some do appear to be large boulders "placed" on top of the bank, but others seem to have been erected. Even so, why are they on top of the bank if they're natural?
Visit it, and decide for yourselves. It's worth it for the views into beautiful upper Dovedale. The Brotherswater campsite, Sykeside Farm, is a few hundred yards away, as is the pub, always a bonus.