7 C.F.R. § 29.1070
That type of flue-cured tobacco commonly known as Western Flue-cured or Old Belt and Middle Belt Flue-cured, produced principally in the Piedmont sections of Virginia and North Carolina and the district extending eastward to the coastal plains region. That portion of this type known as Old Belt Flue-cured, normally characterized by a heavier body and darker color shade and produced principally in the Piedmont sections of Virginia and North Carolina, may be classified as Type 11a; and that portion of the type known as Middle Belt Flue-cured, normally characterized by a thinner body and lighter color shade and produced principally in a section lying between the Piedmont and coastal plains regions of Virginia and North Carolina, may be classified as Type 11b.
7 C.F.R. §29.1070