The Cincinnatian stratigraphic sequence has been much studied, but the depositional environments of many of the sections are still in dispute. I intend to carefully describe a small section of the Grant Lake Formation on a new road cut in northern Kentucky, looking for similarities, differences, and trends in the faunal and sedimentologic make-up of the beds. The Cincinnatian rocks are known to be some of the most fossiliferous of any upper Ordovician deposits, and in my case, the fossils are preserved mostly in shell-beds. From examining the faunal make-up of my section, I will determine its paleoecological history. Studying shell sorting, abrasion, grain size, and preservation will give paleodepositional clues, telling whether origin is autochthonous or allochthonous, and thus helping to determine if storms really were important in the deposition of the beds. Shell-beds have received much attention recently, but no project has been focused on the Cincinnatian sequence, so I hope to compare my results to those of shell-bed workers doing research in other places in the Ordovician period and in other periods. In addition, much of the stratigraphic work done on the Cincinnatian has been focused in southwestern Ohio and southeastern Indiana, with less from my research area in the Grant Lake Formation of northern Kentucky. Thus, my project will help better define the stratigraphy of this area.

I hope to uncover clues to better explain the deposition of storm sequences in the Cincinnatian, and to test Ordovician storm cycle models put forth by others, such as Kreisa (1980). If Kreisa's (1980) or other models do not work for my section, I expect to propose a new model.

Another goal of my project, since I will be working extensively with shell-beds, will be to use characteristics of my beds to determine if depositional environment was similar to or different than those of other shell-beds analyzed by others such as McFarland and others (1999) and Li and Droser (1999). From this I can determine how the position of the Cincinnatian depositional area paleogeographically relates to deposition in other locations in the Ordovician. I know that the Cincinnatian beds are known to have some of the highest fossil contents of any Upper Ordovician rocks, so I may find that my beds are unique in the Upper Ordovician. Even if the beds are quite different from those studied by others, however, I still will be able to find similarites and make comparisons.

Matt Howard


Bedding plane of Grant Lake Formation limestone showing brachiopod-rich shell accumulation.


Matt and one of his Grant Lake Formation sections. Note the alternation between shell-rich limestones and claystones.


Photomicrograph of Grant Lake Formation limestone. Note the brachiopod shell in the upper left corner and the patchy micrite and sparry calcite matrix.

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