The New Oxford Formation is a mapped bedrock unit consisting primarily of sandstones, conglomerates, and shales.

The majority of this early mapping was done by George Willis Stose, Anna Isabel Jonas, and Florence Bascom.

The New Oxford Formation and other formations of the Newark Supergroup were deposited in the Gettysburg Basin, just one of many Triassic rift basins existing on the east coast of North and South America, which formed as plate tectonics pulled apart Pangaea into the continents we see today.

[4] The New Oxford Formation overlies precambrian and paleozoic rocks at the bottom of the Gettysburg Basin.

"[11] Originally known as Palaeosaurus fraserianus Relative age dating of the New Oxford Formation places it in the Late Triassic period, around ~221.5–205.6 Ma (Norian-Rhaetian), possibly reaching as old as 230 Ma (Carnian) in some places.