Complex sentence: All but three of the counties composing S.C. are at least partly in the Pennyroyal region, the exceptions being Edmonson County which is entirely in the Western Coalfield, and McCreary and Whitley counties which are entirely in the Eastern Coalfield.
Split into simpler sentences: All but three of the counties composing S.C. are at least partly in the Pennyroyal region. The exceptions are Edmonson County, which is entirely in the Western Coalfield, and McCreary and Whitley counties, which are entirely in the Eastern Coalfield.