At one time the level of Georgian Bay was well above where it presently sits. Only the very tip of the bluff was above the water. Fortunatly the dolostone is a tough material and it had resisted the abrasive scouring of the glaciers. Fossilized coral reefs are especially resistant, having a structural superiority to the more layered varieties of dolostone. Though dolostone is dissolved by water, it reacts in a different way than does limestone, possibly because of the way that it absorbs water – like a sponge.
About a kilometre along the walking trail from Beachy Cove hikers will spot an impressive sea cave in the clifface. It is situated 14 metres above the shoreline and it is possible to ascend a precariously buttresed series of platforms into its dank interior. From above the view is fantastic. The inside is a vast amphitheatre of fallen rock as though it were some bunker in Lebanon hit by Israeli rocket fire. The air is cool and sound echoes hollowly – swooping swallows pick the everpresent mosquitoes from the air.