Blunt-lobed Cliff Fern - Woodsia obtusa

I think. Found growing in rocky forest on the forest floor near exposed rock, likely sandstone (though some limestone in the park too).

 

Interestingly, Woodsia obtusa is one of the few ferns that can grow both on acidic sandstone and alkaline calcareous limestone (source Short and Spaulding, Ferns of Alabama).

Done