Celia Haddon has some information here....

http://www.celiahaddon.co.uk/standing%20stones/cornwall.html

Apparently William Borlase re-created it?? maybe he left an excavation report somewhere....

Edit.... this should go to page 261 of Naenia Cornubiae written by William Copeland Borlase, its to do with roman coins in cromlechs..

http://www.openlibrary.org/details/naeniacornubiaed00borluoft

it does'nt.. but keep scrolling.