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USGS 18577-PC, Blacktail Creek

Montana
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Next site in MontanaRyburn Gypsum · 5 mi

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Based on our latest records, with claims updated from the BLM on Oct 9, 2026. Land and claims can change quickly, so check before you go.

Minerals on record here

1 mineral

Recorded here: fossil.

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About USGS 18577-PC, Blacktail Creek

USGS 18577-PC, Blacktail Creek is a fossil collection site in Montana, cataloged in the Paleobiology Database. Fossils here come from the Phosphoria Formation, dated to the Lopingian (259.51–251.902 million years ago). The depositional environment is recorded as coastal indet. Documented finds include Leptodus, Lingulidae, Derbyia, Horridonia, Wellerella, Composita.

Geologic setting

Formation
Phosphoria
Geologic interval
Lopingian
Age
259.51–251.902 Ma
Depositional environment
coastal indet.
Recorded occurrences
11
Locality notes

SE1/4, sec. 26, T. 12 S., R. 6 W.

Fossils found here

Leptodus
Strophomenata · Lyttoniidae
Lingulidae
Lingulata · Lingulidae
Derbyia
Strophomenata · Derbyiidae
Horridonia
Strophomenata · Productidae
Wellerella
Rhynchonellata · Wellerellidae
Composita
Rhynchonellata · Athyrididae
Hustedia
Rhynchonellata · Neoretziidae
Rhynchopora
Rhynchonellata · Rhynchoporidae
Permophorus
Bivalvia · Kalenteridae
Aviculopecten
Bivalvia · Aviculopectinidae
Acanthopecten
Bivalvia · Limipectinidae

Records and references

Data: Paleobiology Database collection 95024 (CC BY 4.0) — view the source record

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Questions about USGS 18577-PC, Blacktail Creek

Can you collect at USGS 18577-PC, Blacktail Creek?

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 18577-PC, Blacktail Creek?

Fossil.

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Source: Paleobiology Database.