Not in Avoch, but staying on the Black Isle, Carn Glas is the remains of a chambered Cairn of the Orkney-Cromarty type.
It was excavated in 1906 by Lord Abercromby and latterly by Dr. Anthony Woodham in 1955/56.
Between 2014 and 2015, the site was cleared of vegatation and restored by NOSAS and local interest groups.
http://canmore.org.uk/site/12837