It preserves fossils dating back to the Bashkirian Age of the early Pennsylvanian.

The limestone is locally cherty[2][3] and the upper beds include some thin shale lenses and algal mounds.

[5] The formation contains detrital zircon grains of Cambrian age, which provides supporting evidence for a landmass thought to be present in Pennsylvanian time in the location of the modern Florida Mountains.

[6] It is thought to have been laid down in the Horquilla Seaway, a continental shelf environment on the southwest coast of Pangaea.

[12] In 2001, B. Kues recommended abandoning the Magdalena Group and raising its members, including the La Tuna, to formation rank.