LOCATION: Fond-du-Lac (a suburb of Duluth)
AGE: Upper Precambrian
GENERAL COMPOSITION: Red Sandstone and Siltstones
MissionCreek is an area of exposed Fond-du-Lac Formation. The Fond-du-Lac Formation consists of red Sandstone, and Siltstone (which is 36-68% quartz). The red color comes from the diagenetic process. There is also an interbedding of fissile shale which is mostly lenticular in shape. Most of the Sandstone is well cemented. The fine grained beds are very red in color. Most of the abrupt color changes are at bedding planes with different grain sizes. Sandstone concretions cemented by calcite are also common. They are oval shaped and parallel to the bedding.
Ripple marks, mud cracks and rain imprints are present as well, indicating that the water was shallow and subjected to periods of drying and wetting. The ripple marks show the direction of the current, which is consistent with an Eastward movement.
Because of the Fond-du-Lac Formation's physical isolation, it is difficult to relate this with an equivalent formation of the Lake Superior region.