Corsindae cairn is some 9 meters wide and a 1/2 meter in height. It is completely grass covered. Surprisingly Canmore doesn't mention the two kerbs, one of which still stands the correct way. Excellent views to the south, east and west so understandable for the building reasons.
If visiting Midmar RSC (and you should) keep going up the minor road till it ends. At the junction turn left and stop at the Midmar village hall. The cairn and stone are on the hill immediately to the North east of the car park.
Park in the Midmar village hall car park. The stone is 3/4 of the way up the hill walking in a North Easterly direction. The remaining kerbs of the cairn will be passed, the boulder, held up by chokes is the next large item on the hill.