The Mule Spring Limestone, as its name suggests, is mainly composed of
limestone rocks. These rocks are medium-gray to light-medium-gray, as well as very fine to fine crystalline, and is thin to very thin-bedded in most areas. In the lower sections of the formation, there are also occasional layers, up to thick, of pale-yellowish-brown or greenish-gray
shale, limy
siltstone and silty limestone. In the
Split Mountain, the formation overlies the
Harkless Formation and underlies the
Emigrant Formation, whilst in other areas it overlies the
Saline Valley Formation and underlies the
Monola Formation. == Paleobiota ==