The Sentinal Peak occurrence is located on the western slopes of Adder Mountain, approximately 1 kilometres west of the Kennedy River.

The area is underlain by andesite and basalt of the Upper Triassic Karmutsen Formation, Vancouver Group. These are intruded by granodiorite of the Jurassic Island Plutonic Suite. Some diorite is also exposed.

Disseminated pyrite and minor chalcopyrite occurs in intensely fractured and altered volcanics for a considerable distance south of the intrusive contact. Quartz veins containing pyrite and abundant molybdenite also cut the volcanics from 100 to 500 metres south of the contact. A sample (13913) of this quartz vein material assayed 0.15 per cent molybdenum (Assessment Report 12441).

A wide quartz vein, about 450 metres south-southwest of the contact, is reported to contain magnetite, pyrite, minor chalcopyrite and molybdenite.

In 1983 and 1984, the area was prospected as the Sentinal Peak claim by W. Guppy.