Sentence:  His denials of extensive reading notwithstanding , it is no doubt safe to assume that he has spent time schooling himself in <WSD>Southern</WSD> history and that he has gained some acquaintance with the chief literary authors who have lived in the South or have written about the South . 
Meaning of the word marked with <WSD> tags:  in or characteristic of a region of the United States south of (approximately) the Mason-Dixon line