I was actually planning to visit this enclosure back in May, following an ascent of Carnethy Hill from the south... only for the vision of the onward route to Scald Law - and an apparent large cairn upon South Black Hill - to call the louder. Some other time, then.
Anyway Canmore records the following:
'Part of a palisaded enclosure is visible within the earthwork that crowns the prominent hill to the SE of Turnhouse Hill. The enclosure was probably roughly circular, measuring about 30m in diameter, but the palisade trench is clearly defined only on the N. The earthwork measures 85m by 60m within a rampart and ditch, and there are entrances on the NE and SW. Where best-preserved, the rampart stands up to 1.7m above the bottom of the ditch, but to the S of the field-wall that cuts across the earthwork the defences have been reduced to a scarp by cultivation. Within the interior the positions of at least nine timber houses can be identified, two of them exceptionally well-preserved ring-ditch houses about 13m in overall diameter. (P Hill 1982; RCAHMS 1988).'
Wonderfully sited at the summit of Turnhouse Hill, to the north-east of Carnethy Hill's massive example, Canmore gives the dimensions of this cairn as c12.7m in diameter, rising to a height of c0.4m with 'a clearly-defined internal robbing-scar on the SW' [R Mowat and D R Easton, 13 November 1993].