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Fossil Hunting in Arkansas

beginner friendly Crinoid stems and calyxesBrachiopodsBryozoansBlastoidsShark teeth (Paleozoic)

Arkansas sits at the junction of the Ozark Plateau and the Ouachita Mountains, exposing thick sequences of Mississippian and Pennsylvanian marine rocks loaded with crinoids, brachiopods, and other invertebrate fossils. It is one of the more underrated collecting states in the South.

Why Arkansas?

During the Mississippian and Pennsylvanian periods, roughly 300 to 340 million years ago, shallow tropical seas repeatedly covered what is now Arkansas. These warm waters supported thriving communities of crinoids, brachiopods, bryozoans, and corals. The resulting limestone and shale formations — including the Fayetteville Shale, Pitkin Limestone, and Boone Formation — are now exposed across the Ozark Plateau of northern Arkansas. Crowley’s Ridge in the eastern part of the state adds a Cenozoic component with Eocene marine fossils.

What You’ll Find

Mississippian marine fossils (~320-340 million years old):

  • Crinoid stems and calyxes — Arkansas is one of the best states for crinoid collecting; complete calyxes are the prize find
  • Brachiopods — dozens of species, often well-preserved with shell detail
  • Blastoids — star-shaped echinoderms related to crinoids
  • Bryozoans — lacy and branching colonial forms
  • Goniatite ammonoids — primitive cephalopods found in the Fayetteville Shale
  • Paleozoic shark teeth — small but well-preserved teeth from ancient sharks

Eocene marine fossils (Crowley’s Ridge, ~40 million years old):

  • Fossil clam and snail shells
  • Small shark teeth
  • Sand dollars and echinoids

Best Time to Visit

  • Spring and fall: Most comfortable temperatures for fieldwork
  • After heavy rain: Erosion exposes fresh fossils in road cuts and creek beds
  • Winter: Mild Arkansas winters allow year-round collecting

Tips for Arkansas Collecting

  1. Split the Fayetteville Shale — it breaks easily along bedding planes to reveal fossils
  2. Check creek beds — water erosion concentrates fossils in stream gravels
  3. Look for chert nodules — Boone Formation chert sometimes contains silicified fossils
  4. Visit Crowley’s Ridge for a completely different fossil assemblage than the Ozarks
  5. Bring a hand lens — many Arkansas fossils are small but beautifully detailed

Collecting Sites

Fayetteville Shale Road Cuts

Free Public Access

Washington County

Road cuts in and around Fayetteville expose the Mississippian Fayetteville Shale and underlying Pitkin Limestone. The shale splits easily to reveal crinoid stems, brachiopods, and occasional goniatite ammonoids.

Crinoid stemsBrachiopodsBryozoansGoniatites

Bull Shoals Area

Free Public Access

Marion County

Boone Formation limestone and chert exposures around Bull Shoals Lake yield abundant Mississippian marine fossils. Creek beds and road cuts are the most productive spots. Crinoid columnals are especially common.

Crinoid stemsBrachiopodsBlastoidsHorn corals

Crowley's Ridge

Free Public Access

Craighead and Greene Counties

Crowley's Ridge is a geological anomaly — an erosional remnant of Tertiary sediments rising above the Mississippi River floodplain. Eocene marine fossils including shells, shark teeth, and echinoids are found in exposed cuts and gullies.

Eocene fossil shellsShark teethSand dollars

Devil's Den State Park

Public (Fee)

Washington County

Pennsylvanian sandstone and shale exposures along park trails contain marine fossils. The Lee Creek valley offers good exposures. Surface collecting of loose material is permitted.

Crinoid stemsBrachiopodsBryozoans

Legal Rules for Arkansas

Arkansas allows casual fossil collecting on most public land for personal use. Surface collecting is generally permitted in state parks — do not excavate or use heavy tools. Road cut collecting is legal on public roads. On U.S. Forest Service land (Ozark and Ouachita National Forests), collecting common invertebrate and plant fossils is allowed. Vertebrate fossils on public land require permits. Always get permission on private property.

Read our full legal guide for federal laws and more details.

Key Geological Formations

  • Fayetteville Shale (Mississippian)
  • Pitkin Limestone (Mississippian)
  • Atoka Formation (Pennsylvanian)
  • Boone Formation (Mississippian)

Local Fossil Clubs & Museums