The Long Āgama Sūtra 30.17

30.17

「又須彌山王中級階道廣四十由旬，挾道兩邊有七重寶牆、欄楯七重、羅網七重、行樹七重，乃至無數眾鳥相和而鳴，亦如下階。上級階道廣二十由旬，挾道兩邊有七重寶牆、欄楯七重、羅網七重、行樹七重，乃至無數眾鳥相和而鳴，亦如中階。」

“Furthermore, halfway up Sumeru the mountain king, the stairways are forty yojanas wide. On both sides, the path is bordered by seven walls, seven balustrades, seven nettings, and seven rows of trees … Countless birds of many kinds sing peacefully to each other as they do at the lower stairways.

“At the top of Sumeru the mountain king, the stairways are twenty yojanas wide. On both sides, the path is bordered by seven walls, seven balustrades, seven nettings, and seven rows of trees … Countless birds of many kinds sing peacefully to each other as they do at the middle stairways.”