Regarding it's standing stones I am pleased to share with you this interesting review written by Jos van Geffen who also took the pictures included here. All rights reserved by the author and re-posted by his kind permission.
===> a page with some more pre-historic sites: an earth house and the Stones of Stenness.
Recumbent stone circles, such as this, are only found in north-east Scotland. The are characterised by a large slab placed horizontally between two flanking uprights on the circumference of the circle and a low burial cairn in the centre. These stone circles were made or used probably about 1800-1600 B.C.
Recumbent stone circle at Midmar Kirk
The recumbent is 4.5 metres long and can be seen in the background at the centre.
The text on the information sign at this site tells more about recumbent stone circles in general and this one in particular. I have translated that text also in Dutch (in het Nederlands dus).
Cullerlie: a circle of eight undressed boulder encloses an area consecrated by fires on which eight small cairns ringed by stones were built, probably about 2000 B.C. Two of the cairns contain pits and two other cists. Because the site has been disturbed before, excavations in 1934 revealed only burnt bones, charcoal, and part of a flat knife.
Some more information in English and that text translated in Dutch (Nederlands).
This map (17 kb) shows with a red square where these three photos were taken; date: 28 September 1996.
Source: Jos van Geffen Home Page- All rights reserved by the author - last modified: March 2000