法華義疏 1.224

1.224

「伽耶迦葉」者，伽耶者城名，此云鐵杖城也。在城處修道，故以為名。前出經云「象頭迦葉」也。彼處有象頭山，從山為名也。以彼處有城，故兩出耳。

Regarding "Gayākāśyapa": Gayā is the name of a city, translated here as "Iron Staff City." Because he cultivated the Way at the location of this city, it was taken as his name. An earlier translation of the sūtra calls him "Elephant Head Kāśyapa." At that place there is an Elephant Head Mountain, and the name is derived from the mountain. Because there was a city at that place, both [names] appear.