Aside from salt the formation is made up of dolomite, shale, gypsum and anhydrite.

[1] Outcrops in New York and Michigan contain very little if any salt, since surface water would have dissolved it long ago.

Most of what we know about the formation comes from oil and natural gas drilling operations.

The formation is broken up into several units each represented by a major salt bed.

[1] The upper section or the F1-5 units are where commercially viable salt beds are found.