Shatapatha Brahmana 8.7.1.10

8.7.1.10

atha prathamāyai svayamātṛṇāyai prathamāyai ca viśvajyotiṣa upariṣṭādṛtavye upadadhāti | iyaṃ vai prathamā svayamātṛṇāgniḥ prathamā viśvajyotistadūrdhvānṛtūndadhāti tasmādita ūrdhvā ṛtavo 'tho prajananametaditastadūrdhvam prajananaṃ dadhāti tasmādita ūrdhvameva prajāyate

Now, the (first) two seasonal (bricks) he lays down subsequently to the first naturally-perforated one, and to the first Visvagyotis; for the first naturally-perforated one is this (earth), and the first Visvagyotis is Agni: thereupon he places the seasons, whence the seasons are upwards from this (earth). But generative power there also is therein: he thus places generative power above this (earth); whence procreation only takes place above (upon, not under) this (earth).