Between mileposts 303 and 304, at the southwest edge of Tishomingo State Park, the Natchez Trace Parkway crosses the divide between the Tennessee River and the Tombigbee. Rain falling on the north side runs to Bear Creek and the Tennessee, and from there by way of the Ohio and the Mississippi to the Gulf of Mexico. Rain on the south side runs to Mackeys Creek and the Tombigbee, which reaches the Gulf through the Mobile River and Mobile Bay. The crossing sits on the Eutaw Formation, Late Cretaceous sand and clay that caps the higher ground along the divide.
The Tennessee-Tombigbee Waterway had to cut through the same high ground. Its Divide Cut was dug through sands, clays and silts of the Eutaw, McShan and Gordo formations, more than 150 million cubic yards of unconsolidated sand and clay in all, and the work required lowering the artesian groundwater by as much as 100 feet with deep wells while more than 1,000 piezometers tracked the drawdown. At the south end of the cut, Bay Springs Lock and Dam stands on Mississippian shale of the Hartselle formation.
The cut may also have given fish a way across. The weed shiner, native to the Upper Tombigbee, is treated as introduced in the Tennessee drainage, and ichthyologists suggested in 1993 that it may have arrived through the waterway. A 2005 to 2006 park inventory recorded it in the Bear Creek drainage in Alabama, the first report there.
Getting there
34.6050, -88.2125
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.
