The Lockatong is defined as a light to dark gray, greenish-gray, and black very fine grained sandstone, silty argillite, and laminated mudstone.

[14] Rhabdopelix[8] R. longispinis Gwynedd Isolated vertebrae and other remains, now lost A dubious reptile,[12] likely a chimera consisting of Tanytrachelos, Icarosaurus, and/or fish fossils.

[33][8] Gwyneddichnium[8] G. majore Rhynchosauroides Grey to black laminated mudstone (shale) was deposited in long-lasting perennial lakes.

Others have a lenticular or "pinch-and-swell" shape (with alternating narrow and elliptical cross-sections), which results from the motion of waves at the water surface.

Their layers are very thin and consist of perfectly even, continuous bands of organic material alternating with carbonate (limestone) or clay.

A complete lack of influence from waves or bioturbating animals indicates that the lakes were very deep and anoxic at their lowest extents.

[43] Thin-bedded mudstones with deep mudcracks develop in environments where the lake mud is frequently exposed to dry air.

Vesicles most commonly form in narrow layers of drying fresh mud deposited on top of older, tougher mud-cracked lake sediments.

Vesicular massive mudstone is more chaotic in structure, dominated by numerous vesicles and thin, jagged cracks.

This clumping pattern resembles that of modern salty playas, where dissolved salt gives the lakebed mud a crumbly powdered texture.

They act similar to sand grains and can occur in graded, "pinch-and-swell", and continuous laminae of lake mudstone.

Some crystal clasts grow perpendicular to the layers, often sending out multiple branches as they radiate from a bedding plane.

Random crystal clasts are typically graded, growing larger and more euhedral the deeper they occur within a given layer.

These deposits form in areas equivalent to the edge of the Newark basin, and typically consist of sandstone and conglomerate.

The overlying Passaic Formation has more extensive exposures near the basin margin, and thus a higher prevalence of sandstone and conglomerate.

Lockatong deltas produced sandstone beds with climbing ripple cross-bedding, a specialized sedimentary structure indicative of decelerating water.

Clinoform deltaic sandstone formed in Gilbert deltas, which involve coarse riverbed sediments abruptly being deposited onto a lakebed.

Extensive stacks of this sandstone type indicate rising and falling lake water levels, inducing the deltas to shift and overlap older sediments.

Away from the fault, sandstone becomes more common and conglomerate becomes more rare, indicating that the alluvial fans flatten into dry sandy plains.

Root casts and burrows are abundant in deposits corresponding to the lower portions of an alluvial fan, where porous sediments and a high water table occur simultaneously.

Axial facies are riverbed and overbank deposits from braided rivers flowing down to supply the basin with water and sediment.

The southwestern river system which flowed into the Newark basin is likely the same as that which formed the Hammer Creek Formation further west.

[43] Relative age dating of the Lockatong places it in the Upper Triassic, being deposited between 237 and 207 (±5) million years ago.