Shatapatha Brahmana 8.5.4.8

8.5.4.8

tadāhuḥ | yallokampṛṇāntā anyāścitayo bhavanti nātra lokampṛṇāmupadadhāti kātra lokampṛṇetyasau vā ādityo lokampṛṇaiṣa u eṣā citiḥ saiṣā svayaṃ lokampṛṇā citiratha yadata ūrdhvamā purīṣātsā ṣaṣṭhī citiḥ sa ṣaṣṭha ṛtuḥ

Here now they say, 'Since the other layers conclude with Lokamprinâs (space-filling bricks), and no space-filler is laid down in this (layer): what, then, is the space-filler therein?' The space-filler, surely, is yonder sun, and this layer is he; and this is of itself a space-filling layer. And what there is above this (layer) up to the covering of soil that is the sixth layer, that is the sixth season.