Most of the rock originated from tholeiitic magma series, formed from the shallow melting of the mantle and are very similar to the Mid-Ocean Ridge Basalt, although much thicker more akin to an oceanic plateau.
In the northwest, mudstones, breccia and boulder beds in the Knip Group grade into the Seroe Gracia Formation, which has 300 meters of chert limestone.
There is an unconformity between Cretaceous rocks and this formation, which includes remnants of submarine fan deposits along with andesite metamorphosed to greenschist grade.
The Mainsjie Formation is poorly exposed at the surface, but includes calcareous sands, conglomerates, 10 meters thick that outcrops in eastern Curaçao.
The Seroe Domi Formation is an accumulation of pebble and reef debris that also originated from a submarine fan, that outcrops as cliffs near Willemstad.