Alongside the road at the Ring of Brodgar there are two large mounds. Opposite the modern entrance, practically at road level, is the Plumcake(-shaped) Mound. But the first you encounter is the bulk of Fresh Knowe (presumably called so as against Salt Knowe near the sea loch).
For this you have to go down a slight slope - indeed the lochside edge is practically at loch level and in the present day perilously close to the water's edge, making it damp around this side. Running down to the loch alongside the northern end is a stream a section of which is occupied by some kind of ?concrete tank. Didn't think anything of it at the time, but later found a report of "a fine spring of water at the foot of the tumulus".
The area of Farrer's excavation is well evident from the road as a large blister of dark vegetation. Don't go down with fancy shoes. Looking from the lochside there appears to be a slight saddle at the top of the mound. Also there is a concavity like a big scoop from the southern end. Perhaps there was an even earlier excavation here, and the unconfirmed report of a burial comes from this (it has been another suggestion for the silver fibulae source)?? There could always have been a cist there, as probably with Salt Knowe. Which reminds me of the, admittedly smaller, Queena Fjold barrows which reportedly each only held a single central cist according to the prime investigators.
If the Watch Stone really was part of the arc of a long-gone stone circle I would be inclined to place this site in the same time-frame.
Mr F W L Thomas brings the antiquary's activities to life in 'Account of some of the Celtic Antiquities of Orkney, including the Stones of Stenness, Tumuli, Picts-houses, &c., with Plans'.
The only example of the eliptical or long barrow existing in Orkney (that I am aware of) occurs upon the shore of the North Loch, 100 yards to the eastward of the Ring of Brogar. It measures 112 feet in the direction of its major axis, while its minor is but sixty-six feet, that is, it is twice as long as it is broad. The level ridge on the top is twenty-two feet, and its height twenty-two. The west side is so steep as to be difficult to clamber up. On the opposite side it has been dug into, but not recently, and it may be that from this one the fibulae mentioned by Wallace were obtained.
There is a fine spring of water at the foot of the tumulus upon the loch side, and not unfrequently in summer a group of hungry antiquaries may be seen gazing with fixed attention not into the musty recesses of a kistvaen, but the still more interesting interior of a provision-basket. All these large hillocks are covered by a short green turf, which renders them picturesque and pleasing objects.
p110 of Chapter 13 in: Archaeologia, Or, Miscellaneous Tracts Relating to Antiquity By the Society of Antiquaries of London (1851).
RCAHMS NMRS record no. HY21SE 12 AT HY29601339 was in Petrie's time an elliptical barrow 112' NE-SW, 66' across and 22 ft high. Now it is a 38x26m cairn with a maximum height of 5.7m. Traces of horns at the S and E recently led to its re-assessment as a long cairn like Staneyhill across the loch, but yesterday Nick Card opined the size made it a prime candidate for a Maes Howe type tomb rather - so what about those horns now ?
An 1853 excavation at the north end proved abortive (and was subsequently grassed over), though there is an unsupported account of a burial having been found here this would have come from the pre-1851 dig as Petrie mentions none from Farrar's "considerable trench towards the north end [the earlier excavation was described in 1851 as being from the opposite side to a west climb onto the hill, but if this is the southern end it could be the reason for the putative horns]..