Freda Sandstone:
Youngest rocks along the Keweenawan region. Medium to fine grain rock. Appearance is generally brown, red or tan. Freda Sandstone is also found along the southwest border of Lake Superior in the Upper Peninsula of Michigan, near the Presque Isle River. 
  



C
opper Harbor Conglomerate:



Sediment, similar to sandstone shale. Numerous rounded pebbles joined together by finer materials. Pebbles generally are durable igneous rocks similar to rhyolite and granite.




Copper Harbor Sandstone:

Reddish-Brown rock, with ripples and mud cracks. These are markings from water that flowed in the Porcupines nearly one billion years ago.



Porcupine Volcanics Rhyolite:

Pink and gray volcanic rock. Oldest rock found in the Porcupine Mountains, near Summit Peak.



Nonesuch Shale:

Combination of gray and black shale with siltstone and sandstone. Found along the Presque Isle River.


Lake Shore Traps Basalt:

Basalt found to cap the Escarpment Ridge along the Porcupine Mountains.


Porcupine Volcanic Andesite:

Found along the Upper Carp River near Trap Falls. Andesite and Rhyolite are often grouped together called felsite.





(all above images courtesy of Michigan Department of Natural Resources)