Here are two words which Orberg explains as follows:
Tyrus, -i (f): regio Syriae maritima; incolae: Phoenices, -um (m)
Regnum autem Tyri habebat frater Didonis Pygmalion, rex impius atque scelestus.
Tyrii, -orum (m) < Tyrus, -i (f): regio Syriae maritima; incolae: Phoenices, -um (m)
BUT…then I find the phrase: ’ At in regia magnificum convivium apparatur: triclinium splendide ornatur, veste picta purpuraque Tyria sternuntur lecti, mensae vasis argenteis atque aureis teguntur.
What does ‘Tyria’ mean here: Does Tyrus, -i (f) the region, have Tyria in the ablative…?