Holder Formation

The Holder Formation is a geologic formation in the Sacramento Mountains of New Mexico. It preserves fossils dating back to the late Pennsylvanian.

Description

The Holder Formation consists of limestone, red and gray calcareous shale, sandstone, and conglomerate. The maximum thickness is. The formation overlies the Beeman Formation and is overlain by the Laborcita Formation.
The formation is interpreted as a shallow-shelf marine formation of Virgilian age during a global ice age.

Fossils

s are present at the base of the formation. These are up to thick. They are composed of uncalcified cup-shaped phylloid algae surrounded by masses of beresellid algae.

History of investigation

The unit was first named by Lloyd C. Pray in 1954 and a type section was designated in 1959. Pray originally assigned the formation to the Magdalena Group, but the Magdalena Group has subsequently been abandoned.