Base map: USGS Cleveland, Ohio; Pa., U.S., Ont., Can. (4th ed. 1972 rev.)
"Areal density of photo linears occurring within a 5000 meter square grid."
Includes location maps.
Title assigned by cataloguer.
prepared ... by Richard A. Struble and David A. Hodges.
Scale 1:250,000 ; Transverse Mercator projection.
Depths shown by bathymetric isolines.