Caster Identified
& Traced Key Stratal Surfaces Across Study Area
Found Stratal Surfaces
Obliquely Intersect Formations (Magnafacies Belts)
Interpreted Stratal Surfaces as Planes of
Contemporaneity
Planes of
Contemporaneity Bound Groups of Parvafacies (The Parts of each Formation which were deposited
during a given period of time)
Formations are Time-Transgressive
FORMATIONS / MAGNAFACIES
Planes
Of
Contemporaneity
Upper Devonian: NW
Pennsylvania
K.E. Caster (1934)