An obscure reference to an outer circle at Duddo. It isn’t clear if the author is talking about an outer circle of stones, or a bank. Given the profusion of henges in the area, probably the latter. The barrow to the north is a new one to me too.
Canon Raine in his massive volume 1852 on North Durham (very north indeed!) writes:
On an eminence in the middle of a field a mile north west of Duddo stands a time and weather worn memorial of the Druidical period. The temple or whatever it may have been, has been of the usual circular shape, surrounding at intervals a plot of 36 feet in diameter. Four stones alone are standing, the tallest of which measures 6 feet9 inches in height, by 13 feet in girth: a fifth is extended upon the ground, In a broken state, the rest have been removed. The remains of an outer circle were a while ago discovered at the usual distance*. The situation of this hillock is of a peculiar nature; it rises as it were, in the middle of a large natural basin two miles in diameter and might have been seen at one and the same time by thousands upon thousands of assembled devotees. A small barrow at the foot of the hill on the north side, much levelled by the plough, has I believe never been opened.
*My emphasis