Mule Spring Limestone
The Mule Spring Limestone is a geologic formation in the Saline Range of eastern California and Split Mountain and Goldfield Hills of Nevada.
It is also to be found in the Inyo Mountains and White Mountains.
It preserves fossils, such as trilobites, and algal structures like Girvanella, dating back to the Cambrian period.
Geology
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
The Mule Spring Limestone contains examples of Archaeocyatha, a clade of sponges that went extinct during this time, as well as a collection of trilobites.Arthropoda
| Genus | Species | Notes | Images |
| Bristolia | Bristolia sp.B. harringtoniB. insolensB. bristolensisB. anterosB. fragilis | Biceratopsid trilobites. | |
| Peachella | Peachella sp. | Biceratopsid trilobite. | |
| Mesonacis | Mesonacis sp. | Olenellid trilobite. Mesonacis sp. previously described as Fremontia sp. which was later synonymised into Mesonacis. | |
| Olenellus | Olenellus sp.O. puertoblancoensis | Olenellid trilobite. Olenellus sp. previously described as Paedumias sp. which was later synonymised into Olenellus. | |
| Onchocephalus | Onchocephalus sp. | Ptychoparid trilobite. | |
| Ptychoparioid |
| Ptychoparid trilobites. | |
| Bonnia | Bonnia sp. | Dorypygid trilobite. | |
| Crassifimbra | Crassifimbra sp. | Trilobite, family unknown. |
Porifera (Sponges)
| Genus | Species | Notes | Images |
| Archaeocyathus | Archaeocyathus sp. | Archaeocyathide sponge. |
Flora
| Genus | Species | Notes | Images |
| Girvanella | Girvanella sp. | Cyanobacteria structures. |