Windom Shale Member of Moscow Formation reaches a maximum thickness of 60 m in the eastern Finger Lakes area of NY. Here it consists of medium to dark gray fossiliferous mudstones and shales with thin concretionary limestone beds and can be divided into approximately 15 informal traceable units and a number of thin, localized shell-rich beds. Simpson Creek bed is a 1-cm-thick, persistent, shell rich bed that unconformably overlies the Spezzano Gully beds from Genesee Valley eastward to Barnum Creek on the west side of Cayuga Lake. Bed is particularly rich in the small brachiopod EMANUELLA PRAEUMBONA, which is commonly mixed with abundant fragmentary brachiopod material, crinoidal hash, and other debris. Bed locally appears to be a lag deposit. Underlies Gage Gully beds. Age is Middle Devonian (Givetian).

Source: GNU records (USGS DDS-6; Reston GNULEX).