Cormorant Rock, and the shore of Red Island.
Again you can see piles of rocks, that look as though they just dropped onto the muddy bottom.
Cormorant rock is very prominent, rising sharply to 1m above the water, but the shallow rocky area associated with it extends a substantial distance towards the centre of the lake.
Most of the "rock piles" on the lake occur in water of less than 20ft depth. The remainder of the lake bottom is soft mud.
The image linked here is very large (2mb) and enables one to clearly see individual boulders.