A survey of the Cosby Patent in 1788, just one year prior to the mapping of the Oriskany Patent to the west, captures the line of the Mohawk River, which runs through the middle of it (below).

As so often happened with early land surveys in uninhabited areas, surveys were run between easily identifiable natural landmarks. In this case the western boundary of the parcel falls exactly at the junction of the "Sedaghqueda Creek" and the Mohawk River.

Thus we can be certain that no part of the search area, which lies entirely west of the Sauquoit Creek, falls within the old Cosby Patent.