From Black Tor, walk down into the stream valley (keeping the aqueduct about 400 yards to your right). On the opposite hillside, you should be able to make out the avenue/row ahead of you. Cross the stream using one of the metal bridges.
The circle is quite attractive in a very pleasant setting and has 14 stones, the tallest about 1m high.
The stone avenue leads up to the circle and is about 140m long.