俱舍論記 18.22

18.22

「要異處破至對必無能」者，釋異處。異處謂羯闍尸利沙山，此云象頭山，山頂如象頭故以名焉。去鷲峯山北可三、四里，同一界內，天授住彼而破僧故，非對大師。舊云伽耶山者，訛也。以羯闍之與伽耶音相近故，故謬傳爾。然西方別有伽耶山，去鷲峯山一百五十餘里，非同一界，非破僧處。

"It must be split in a different place […] he would definitely have had no power" explains 'in a different place'. The different place means Mount Gajasīrṣa, which here is translated as 'Elephant Head Mountain', named so because the summit of the mountain resembles an elephant's head. It is about three or four li north of Vulture Peak, within the same boundary; Devadatta stayed there and split the Saṃgha, not in the presence of the Great Teacher. The older version saying Mount Gayā is an error. Because the sounds of 'Gaja' and 'Gayā' are close, it was erroneously transmitted. However, in the Western Regions there is a separate Mount Gayā, more than one hundred and fifty li from Vulture Peak, not within the same boundary, and not the place of the schism.