This is a triangular blade, corner notched, usually with fine serrations. It dates Early-Middle Archaic and is more common south of the Northeast region. Base is straight to convex, barbs point downward, corner notching usually deeper then in the later Brewerton Corner Notched.
A description from lithics-net:
From the Maryland typology guide:
This example is from Ma.:
A description from lithics-net:
From the Maryland typology guide:
This example is from Ma.: