High Rock Bay
Lake Shore Traps
Portage Lake Volcanics
Copper Harbor Conglomerate

At High Rock Bay and the area to the north, many good exposures of the Lake Shore Traps can be seen along the wave washed shoreline.  There are contacts between conglomerates and the lavas and exposures of many flow tops with amygdules, including agates. The shoreline takes a beating from strong winds, so the beaches generally have cobbles. Offshore shallow water areas have been productive for sizable agates, as the Lake Shore Traps generally do carry agate amygdules.

Looking North from Rocket Range

Liesegang in Lake Shore Traps, through the water.


Keweenaw Pt

AE Seaman