This Cairn serves two purposes. It marks the largest Indian Ossuary as well as the site of the former summer residence of Sir Peregrine Maitland, Lieutenant-Governor of Upper Canada from 1818-1828.
Both of these sites are 200 yards from this cairn. The Ossuary is 200 yards north-west, the 'cottage' is 200 yards north-east.
Please note the related web page link on the ossuary above to obtain more info. (You can google the Maitland summer residence if you want - I found the ossuary personally more interesting.)
TO FIND THE CACHE: Solving for last three digits of coords only! (Assume a=1)
For the NORTH coordinates:
ADD to the north coords given on the cache page to the A=1 equiv of all letters that are in quotations AND apostrophes. Then add 11.
For WEST coordinates (last 3 digits only):
SUBTRACT from the West coordinates given on the cache page the number of stones on the lowest level/base of the structure. Then subtract 15 more.