This Clava passage grave appears to be built on a platform but this is perhaps illusory, formed by ploughing round the site combined with the spread of cairn material from the internal mound.
The latter has a contiguous kerb of 13.0x13.5m diameter. This is graded towards the entrance to the south, where the stones are up to 1.05m high. The two end stones to the passage protrude slightly beyond the kerb.
This passage is c5.0m long and leads to a central circular chamber of c3.5m diameter. Much of both these features is buried, the chamber roof has collapsed but much of the passage may still retain its capstones. Two of the latter are visible. The stone circle is 2.0-3.0m outside the kerb with the space increasing to the south. The stones are also graded in this direction and their spacing becomes wider here.
Quoting from p60 of The Design and Distribution of stone Circles in Britain; a Reflection of Variation in Social Organization in the Second and Third
Millennia BC. – A thesis submitted for the Degree of Doctor of
Philosophy in the Department of Archaeology and Prehistory. University of Sheffield. December 1987. by John Barnatt.