The above pictures are of sandstone beds from a quarry in North Arkansas developed in a rock formation called the Batesville Sandstone. Though it formed in a marine setting, the Batesville is typically composed of fairly homogeneous, flat-bedded rock with little evidence of inhabitation. This spot is an exception. The pictures clearly indicate the depositional environment was teaming with sea life at the time the sediment was emplaced.
The abundant trace fossils, which preserve the activity of organisms rather than their physical form, show a variety of behaviors common to marine invertebrate animals that lived in Arkansas more than 330 million years ago. Remnants of grazing traces of various snail and worm-like critters (A), resting traces (starfish; B), Dwelling burrows (sea-anemone or bivalve?; C), and locomotion trails (D) are indicators of the conditions present in North Arkansas near the end of Mississippian time.
Office of the State Geologist Blog 