USGS "blue file" Loc. 13390 is a fossil collection site in Fergus, Montana, cataloged in the Paleobiology Database. Fossils here come from the Otter Formation, dated to the Serpukhovian (330.3–323.4 million years ago). The depositional environment is recorded as lagoonal and the tectonic setting is cratonic basin. Documented finds include Longiclava tumida, Crinoidea, Petrocrania modesta, Linoproductus, Pugnoides, Cleiothyridina hirsuta.

Geologic setting

Formation: Otter
Geologic interval: Serpukhovian
Age: 330.3–323.4 Ma
Depositional environment: lagoonal
Tectonic setting: cratonic basin
Recorded occurrences: 11

Geology notes

Environment was often hypersaline. Numerous gypsiferous beds are common, as well as stromatolites ("calcareous algae").

Locality notes

Center n1/2 sec.8 t13n r21e.

Fossils found here

Longiclava tumida

Anthozoa · Hapsiphyllidae

Crinoidea

Petrocrania modesta

Craniata · Craniidae

Linoproductus

Strophomenata · Linoproductidae

Pugnoides

Rhynchonellata · Petasmariidae

Cleiothyridina hirsuta

Rhynchonellata · Athyrididae

Composita laevis

Rhynchonellata · Athyrididae

Composita

Rhynchonellata · Athyrididae

Eumetria

Rhynchonellata · Retziidae

Spirorbis

NO_CLASS_SPECIFIED · Serpulidae

Ostracoda

Records and references

Data: Paleobiology Database collection 5653 (CC BY 4.0) — view the source record

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Questions about USGS "blue file" Loc. 13390

Can you collect at USGS "blue file" Loc. 13390?

It depends on who owns the land and whether a mining claim covers it. BLM land usually allows hand collecting for personal use, national parks allow none, and private land needs the owner’s permission. Pro members see the owner and any claims at this spot.

What minerals are found at USGS "blue file" Loc. 13390?

Fossil.

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What to bring

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Meteorite nearbyA 17.6 kg iron meteorite was found at Roundup in 1990, 26 miles from here.

Source: Paleobiology Database.