File:Logan Formation over Cuyahoga Formation (Lower Mississippian; Dugway Outcrop, Newark, Ohio, USA) (32767557975).jpg

Siliciclastic sedimentary rocks in the Mississippian of Ohio, USA.

This locality has an exposure of the Logan Formation over the Cuyahoga Formation. Both units are successions of mixed siliciclastics and are Early Mississippian in age. Two of the four members of the Logan Formation are present at this site. The rocks at the very top are the basal beds of the Byer Sandstone Member. Below that is a relatively thin bed called the Berne Conglomerate Member (the base of the unit is at approximately the level of the bottom of the sharply bent tree near center-top).

Disconformably below the Berne Conglomerate is the Cuyahoga Formation. The upper beds are sandstone-dominated and have historically been referred to as a distal facies of the deltaic Black Hand Sandstone. The latter unit is now known to be an incised valley fill deposit that is temporally and genetically unrelated to the Cuyahoga Formation. The sandy upper Cuyahoga Formation at this locality appears to be an unnamed member (here referred to as the "Dugway Member"). Below that is a dark gray mudshale-dominated unit called the Raccoon Shale Member, which is named after nearby Raccoon Creek. The Raccoon is sparsely fossiliferous - trace fossils are typically the only biologic remains. Body fossils are scarce.

Stratigraphy: Byer Sandstone Member over the Berne Conglomerate Member over the Cuyahoga Formation, Waverly Group, Kinderhookian to Osagean Stages, Lower Mississippian