Edgecliff Chert is associated with the Edgecliff Cherty Limestone Member of the Onondaga Formation of New York, Ontario, and into Pennsylvania occurring as beds and nodules.  Named for exposures in Edgecliff Park southwest of Syracuse with exposures occurring from Buffalo to the Helderbergs, in western New York and in Ontario.  Exposures also occur in the northern Hudson River Valley.  The Clarence Member of western New York is considered the informal facies of the Edgecliff Member and is made up of 40 to 70 % chert.