Where to Search for Byzantine Arkion?

The toponym ‘Arkion’ appears on several seals from the 11th century. A Christodoulos was protospatharios chartoularios and episketites τοῦ Ἀρκίου; an Ardabasdos was protospatharios of the manglabion and topoteretes τοῦ Ἀρκί(ου); an Asotas was horreiarios of Kios or Ἀρκίου; and a Michael was also horreiarios of Kios or Ἀρκήου (in the two last examples we assume a haplography of the letters Alpha and Rho). The author dismisses an identification with Arka, south-southwest of Melitene, a well-known bishopric in the metropolis of Melitene, as this name is always found as feminine, but prefers an identification with the Armenian district of Hark or Hark‘ in the region of Turuberan, on both sides of the Murat river, north of Tarōn. In the De administrando imperio this region is called τὸ Χάρκα.