Shatapatha Brahmana 8.7.4.12

8.7.4.12

athātaścitipurīṣāṇāmeva mīmāṃsā | ayameva lokaḥ prathamā citiḥ paśavaḥ purīṣaṃ yatprathamāṃ citim purīṣeṇa pracādayatīmaṃ tallokam paśubhiḥ pracādayati

Now, then, the consideration of the layer-fillings. The first layer is this (terrestrial) world; and the filling of soil means cattle: thus, in covering the first layer with a filling of soil he covers this (terrestrial) world with cattle.