At about milepost 236.5, south of Witch Dance Hill, the Natchez Trace Parkway crosses a cap of red sand lying on top of the Cretaceous. The 2023 Office of Geology map of the Houston East quadrangle shows dozens of these patches of Clayton Formation scattered along the ridge crests above the Prairie Bluff Chalk, and the motor road runs over one that reaches the 520 foot contour. The Clayton is Paleocene, laid down after the mass extinction that ended the Cretaceous, so the base of every cap is the Cretaceous-Paleogene boundary. The formation is named for Clayton, Alabama.
The map describes massive to cross-bedded red quartz sand up to about 50 feet thick, resting unconformably on the Prairie Bluff and in places cut down into it, with limonite near the base. A 1943 survey of Pontotoc County called the contact part of the widespread Cretaceous-Paleocene unconformity of the Gulf Coastal Plain, marked in places by quartz pebbles and reworked fossils.
At a landfill section in Chickasaw County studied in 2021 the contact is sharp, and the basal Clayton is about 2.5 meters of cross-bedded coarse quartz sand; elsewhere in the region the lowest Clayton bed is a spherule-rich sand that researchers suggest may be related to the Chicxulub impact. Witch Dance Picnic Area, at milepost 233.2, sits on another cap.
Getting there
33.9537, -88.9300
Locations are approximate and may be inaccurate, on private land, or otherwise inaccessible. Check before you travel.
Hear it from the road
Whistlestop is an audio tour guide app that tells you this story automatically when you drive past. No searching, no tapping, nothing to ask.
