Cobleskill Formation Research In Central New York
Auburn Eastward To The Rock Cut Gorge Near Syracuse, New York
Samuel J. Ciurca, Jr., Rochester, New York
Abstract Presented before the Rochester Academy of Science Fall Paper Session at
Rochester Institute of Technology, Rochester, New York,  November 15, 2003
Page Started May 15, 2003
A roadcut near Marcellus Falls, New York,  exposes massive beds of cherty dolostone that are termed "Cobleskill Formation'" in most literature.  However, lithologically there is no similarity between the beds exposed here and the type Cobleskill Limestone of Eastern New York.  Additionally, near the top of the beds exposed at Marcellus Falls, and just below the overlying Chrysler Formation, occurs a small patch reef.  This reef and the associated cherty dolostone is referred to as the  "Martisco Reef Complex" (Ciurca, 2003).
ABOVE: Reef core?  Highly dolimitized massive beds of the reef complex.  White areas are the mineral Dolomite. Some of the beds are vuggy and lined with crystals. Others contain much Quartz in the form of silicified stromatopor-  oroids or black Chert seams. Stick is 1 meter in length.
   A sledge has to be used to sample this rock.  It is so resistant  Nevertheless, continued pounding is releasing some of the secrets of this cryptic reef complex.
   The major challenge is to relate these beds to the se- quences known at other localities, particularly the Akron Dolostone of Western New York and the anomolous beds exposed along Owasco Outlet at Aburn, New York.
Irregular bedding and stylolitic contacts characterize the massive reef beds exposed here. Fossils are difficult to identify due to recrystallization.  However, the silicified stromatoporoids preserved here provide evidence as to the nature of the mound occurring near the top of this exposure.  Brecciation is prominent in certain beds and indicates the high-energy environment in which these beds were deposited.
AT LEFT: Silicified stromatoporoid (Chert) in massive dolostone (closeup).  Several stromatoporoid speci- mens were observed at this locality.  Detailed study of this locality should provide additional information as to the nature of the exposure and its relationship to the occurrence of eurypterids in the region.
   Exposures at the Rock Cut Gorge near Syracuse in- dicate that the reef complex extends at least into this region.  And the eurypterid bed associated with the reef also extends into the Syracuse region.  Detailed meas- urments of the sections are in progress.
AT RIGHT: Black Chert 'ribbons' are abundant in some of the layers at this exposure.  Fossils appear to be rare or so highly dolomitized that there presence is overlooked. 
   Layers of Chert have been observed at the Rock Cut Gorge southeast of Syracuse and also, minimally, at ex- posures along
Owasco Outlet at Auburn, New York.
   The material presented on this page is part of a presen- tation to be given before the annual Rochester Academy of Science Meeting at Rochester Institute of Technology in November of 2003.
Owasco Outlet (River) North of Auburn, New York