The two fault-bound basalt islands stand offshore at Wasson Bluff offer vivid lessons in geobiology. The near island, ‘Big Brother’, has sheer cliffs that offer nesting habitat for vulnerable Peregrine falcons. Between the islands and shore, threatened rock-boring clams (Barnea truncata) chose only the Jurassic red mudstones of the McCoy Brook Formation as their most northerly global habitat.

Geological Formation: North Mountain and McCoy Brook formations
Age: Late Triassic-Early Jurassic (circa 200 million years)
Directions: Same as for Wasson Bluff, from where the Brothers are safely viewed. Warning: the incoming tide rushes around the Brothers at surprising speed. Walking to the islands at low tide can be very dangerous due to the speed of the returning tide and is therefore not recommended.