The McCoy Brook Formation is a geological formation dating to roughly between 200 and 190 million years ago and covering the Hettangian to Sinemurian stages. The McCoy Brook Formation is found in outcrops around the Bay of Fundy, Nova Scotia.

The McCoy Brook Formation rests on the North Mountain Basalt, one of the volcanic flows associated with the Triassic–Jurassic boundary in the Newark Supergroup. The base of the McCoy Brook Formation is probably within 100,000 to 200,000 years of the boundary.

This thin unit (9 m) of lacustrine sediments is preserved in six small synclinal outcrops around Scots Bay on the west side of the Blomidon Peninsula. Originally named as the Scots Bay Formation, it is now correlated with the lowermost part of the McCoy Brook Formation, where it is referred to as the Scots Bay Member. The Scots Bay Member accumulated in an aerobic lake on the floor of the subtropical Fundy Rift Valley, associated with Silica-rich Hydrothermal Springs derived from the CAMP vulcanism, where the biota is composed of algal Stromatolites, Oncolites, Charophyta, Ostracoda, Gastropoda, Conchostraca, fish bones, calcispheres and logs.