The Ramseyburg Member which is composed of alternating turbidite sandstone units with interbeds of shale and siltstone.

And the Pen Argyl Member which is the uppermost slate unit with some minor phyllite and shale beds.

Turbidites are common in the Martinsburg due to underwater landslides stirring up sediments and rushing down a slope.

A modern analog to the depositional history of the Martinsburg might be the Australia-East Timor tectonic setting.

Other quarries that exist in the shale partings use the rock as crushed stone for structural and other earth fill operations.