We built a cross-shelf Paleocene-Eocene Thermal Maximum (PETM) depositional model for input of muds from the “Appalachian Amazon” where large amounts of fluid mud creating expanded PETM records. New cores from Medford, NJ preserve the carbon isotope excursion (CIE) onset overlain by the lower portion of the CIE “body/core.” We use δ13Cbulk, percent CaCO3, and percent coarse fraction (>63 µm) to correlate Medford with records along a paleoslope dip transect, showing that updip locations preserve expanded sections of the earliest portion of the CIE (the onset) in contrast with downdip locations where the final section of the CIE (the recovery) is preferentially preserved. This pattern implies that the fluid mud was deposited in prograding clinoform foresets. Our subaqueous-clinoform delta model explains the variability of the CIE records and provides a framework for future PETM studies in the region.