Uploader's Comments

This is a military structure which dates from the 1920s and was built on the site of a chapel which was located on a mound, possibly a broch. It is possible that red sandstone blocks used in its construction, some of which can be seen around the partially blocked up doorway, may be from the chapel (ref http://canmore.rcahms.gov.uk/en/site/3513/details/sanday+colli+ness/ ).