The literary term would be an oxymoron. Oxymorons are “a figure of speech in which apparently contradictory terms appear in conjunction (e.g. faith unfaithful kept him falsely true ).”
Explanation:
The Blue Ridge Mountains are a physiographic province of the larger Appalachian Mountains range. The mountain range is located in the eastern United States, and extends 550 miles southwest from southern Pennsylvania through Maryland, West Virginia, Virginia, North Carolina, South Carolina, Tennessee, and Georgia.[1] This province consists of northern and southern physiographic regions, which divide near the Roanoke River gap.[2] To the west of the Blue Ridge, between it and the bulk of the Appalachians, lies the Great Appalachian Valley, bordered on the west by the Ridge and Valley province of the Appalachian range.