From the Stratigraphic Lexicon for Michigan:

 

AU TRAIN FORMATION

Early Ordovician

Related terms : Prairie du Chien Group, Hermansville Limestone.

Lithology : Sandy dolomite (top) to dolomitic sandstone, distinctly glauconitic, in part, 125-300 feet (38-91.5 meters) plus: Northern Peninsula, Michigan.

Type locality : Au Train Falls, Alger County, Michigan: Hamblin (1958).

Additional references : Catacosinos (1973), Catacosinos and Daniels (1991b), Dott (1991), Haddox and Dott (1990).

Remarks : Formal surface term, equivalent in part to the Prairie du Chien Group.

 

MUNISING FORMATION

Late Cambrian

Related terms : Munising Group.

Lithology : Sandstone and conglomerate, about 200-250 feet (61-76 meters): Northern Peninsula of Michigan.

Type locality: Munising, Michigan: Lane and Seaman (1907).

Additional references : Catacosinos (1973) and Catacosinos and Daniels (1991b), Hamblin (1958), Thwaites (1934). See Berquist (1937) and Lake Superior Sandstone.

Remarks : Formal surface term. Members consist of Basal Conglomerate, Chapel Rock and Miner's Castle. The correlation of all the members in the Formation to those in the Group needs clarification.

 

MINER'S CASTLE MEMBER

Late Cambrian, Munising Formation

Related terms : Basal Conglomerate, Chapel Rock Member, Munising Group.

Lithology : Sandstone, 140 feet (42.7 meters): Northern Peninsula, Michigan.

Type locality : Miner's Castle in the Pictured Rocks cliffs, Michigan: Hamblin (1958).

Additional References : Catacosinos (1973), Catacosinos and Daniels (1991b), Haddox and Dott (1990).

Remarks : See Munising Formation. Extended into Indiana by Droste and Patton (1985), also see Cohee (1945b). odified by Catacosinos (1973) in the Southern Peninsula, the Group consists of Eau Claire Formation, Galesville Sandstone and (top) Franconia Formation. Briggs (1968) included the Mount Simon Sandstone in his use of the Group. An informal term that needs evaluation, possibly formal proposal. The correlation of all the members of the Group to those in the Formation needs clarification.

 

CHAPEL ROCK MEMBER

Late Cambrian, Munising Formation

Related terms : Basal Conglomerate, Miner's Castle Member, Munising Group.

Lithology : Sandstone, 40-60 feet (12-18.3 meters): Northern Peninsula of Mi.

Type locality : Chapel Rock, eastern end of the Pictured Rocks cliffs: Hamblin (1958).

Additional References : Catacosinos (1973), Catacosinos and Daniels (1991b), Haddox and Dott (1990).

Remarks : Formal surface term, middle member of Munising Formation.

 

BASAL CONGLOMERATE MEMBER

Late Cambrian, Munising Formation

Related terms : Chapel Rock Member, Miner's Castle Member, Munising Group.

Lithology : Conglomerate, 2-15 feet (less than 1- 4.5 meters): Northern Peninsula of Michigan.

Type locality : Grand Island, Michigan: Hamblin (1958).

Additional References : Catacosinos (1973), Catacosinos and Daniels (1991b), Haddox and Dott (1990).

Remarks : Formal term, unnamed basal member of the Munising Formation.

 

JACOBSVILLE SANDSTONE FORMATION

Middle Proterozoic

Related terms : Freda sandstone, Pre-Mt. Simon clastics.

Lithology : Conglomerate and sandstone, ranging from 15 feet to at least 1,800 feet (4.6-549 meters, plus): Northern Peninsula of Michigan, possibly Lower Peninsula subsurface.

Type locality : Jacobsville, Michigan: Lane and Seaman (1907).

Additional references : Catacosinos (1981), Catacosinos and Daniels (1991b), Hamblin (1958) and Kalliokoski (1982, 1988).

Remarks : Formal surface term.