Sharon Formation Research Paper

Sedimentology of the Sharon Formation

The Sharon Conglomerate is the lowest deposits in the Pennsylvanian of Ohio, and a member of the

Pottsville Formation (Conrey, 1921).

Mrakovich (1974) describes the deposit as “a sheet-like body having a comparatively flat top and a very irregular base which lies unconformably on

Mississippian strata of the Cuyahoga Formation.”

He notes that the deposit is mostly cemented quartz arenite, but that narrow lenses of shale and siltstone occur. Conrey’s (1921) book on the geology of Wayne

County mentions some plant remains in these lenses.

Global drop in sea level during late Mississippian and early Pennsylvanian caused a period of deep erosion into the Logan and Cuyahoga rocks of the

Mississippian. The top

The deposit in northeast Ohio demonstrates southerly paleocurrents. (Ninke & Evans, 2002)

Description of the section a more detailed description will be provided. The following is a rough descriptions of the layers starting about a meter below the course of the creek.

1. Course conglomerate: This is found when removing large sections of siltstone and shale from the creek bed. May underlie most of the deposit.

2. Soft shale: a fine black shale occurs for about 1/2 meter. It contains many lycopod cones and a few other fossils. It falls apart easily.

3. Hard siltstone: a much harder and heavier siltstone type of rock overlies the shale. It starts out gray color and becomes red and yellow as it moves higher. This is the layer where most of the fossils are found. Splitting is sometimes very difficult because of the hardness. The layer is about a meter thick. This layer is much more erosion resistant.

Flora fossils found in the siltstone include lycopod leaves and branches, cordaites, megalopteris, palaeopteridium, and a pinnate cycad frond that will be described further. Seeds include