Shirley Basin: Opalized Wood Rockhounding in Carbon County, Wyoming

Updated June 2026

Shirley Basin is a mapped rockhounding spot in Carbon County, Wyoming. Reported finds include opalized wood. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Carbon County
State: Wyoming
Coordinates: 42.33184, -106.25853

Geology at Shirley Basin

This spot sits on Wind River Formation, mapped as claystone that formed roughly 56 to 34 million years ago. Sedimentary beds like these are the typical host for petrified and silicified wood, which weathers out as durable float on slopes and in washes.

Mapped unit: Wind River Formation
Age: 56–34 Ma (Eocene)
Rock types: claystone
Elevation: 7,020 ft

Geologic mapping via Macrostrat and the underlying state geological survey maps (CC BY 4.0). Bedrock at the surface can vary within a mapped unit.

Best time to visit Shirley Basin

Best months: April to October. Typical highs run 81°F in midsummer and 28°F in midwinter, with winter lows near 1°F. At about 7,020 ft, snow can block access from late fall well into spring, so check conditions outside of summer.

Climate normals: NOAA 1991-2020 monthlies, SHIRLEY BASIN station (8 mi away).

Land & collecting status

Generally open to casual rockhounding

Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig.

Public-land rules vary by agency, season, and field office. The RockHoundR app pulls live BLM, USFS, NPS, and tribal overlays so you can see exactly which agency manages the ground at this spot.

Sources & verification

Spot details combine the public RockHoundR location dataset, normalized mineral labels, agency land-status checks in the app, and community submissions. Coordinates are approximate until verified in the field.

State guidance last verified: April 1, 2026

BLM Wyoming
Wyoming State Geological Survey
Fossil Butte National Monument
Community submissions reviewed against published agency rules

Found at Shirley Basin

Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

Opalized Wood Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Shirley Basin.

Shirley Basin FAQ

Where is Shirley Basin?+

Shirley Basin is in Carbon County, Wyoming, at 42.33184, -106.25853.

What rocks and minerals can you find at Shirley Basin?+

Shirley Basin is reported to produce Opalized Wood.

Is collecting allowed at Shirley Basin?+

Generally open to casual rockhounding. Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Shirley Basin?+

A rock hammer, sturdy gloves, and a padded bag cover petrified wood hunting. Most pieces are surface float, so walking slopes and washes beats digging.

When is the best time to visit Shirley Basin?+

The most comfortable months at Shirley Basin are April to October. At about 7,020 ft, snow can block access from late fall well into spring, so check conditions outside of summer.

How do I get to Shirley Basin?+

Open the directions link to navigate to 42.33184, -106.25853 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Wyoming

See all 82 Wyoming spots →

Open Shirley Basin on the map

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