Limestone road cuts: Turritella Agate Rockhounding in Coryell County, Texas

Quick details

Access

Public area

County

Coryell County

State

Texas

Nearest road

Farm-to-Market Road 107

Postcode

76561

Coordinates

31.39229, -97.54617

Geology at Limestone road cuts

This spot sits on Undivided parts of Washita and Fredericksberg Groups, mapped as claystone and limestone that formed roughly 145 to 100 million years ago. Chert and agate nodules typically form inside carbonate rock like this and weather out as tough, waxy lumps in soils and creek beds.

Mapped unit

Undivided parts of Washita and Fredericksberg Groups

Age

145–100 Ma (Early Cretaceous)

Rock types

claystone and limestone

Elevation

720 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 Limestone road cuts

Best months: September to May. Typical highs run 95°F in midsummer and 59°F in midwinter, with winter lows near 34°F. Summer heat here is intense, so carry more water than you think you need and work the early morning.

Climate normals: NOAA 1991-2020 monthlies, MCGREGOR station (9 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

• Texas Parks and Wildlife Department
• Bureau of Economic Geology — Texas geology
• Big Bend National Park — Rules
• Community submissions reviewed against published agency rules

Found at Limestone road cuts

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

• Turritella AgateEncyclopedia →