Śatapatha Brāhmaṇa ("of a hundred paths") 8.2.2.3

8.2.2.3

te 'bruvan | aśvinau vā idaṃ sarvamabhūtāmaśvibhyāmevāśvinościtimanūpadadhāmahā iti te 'śvibhyāmevāśvinościtimanūpādadhata tasmādetāmāśvinī citirityācakṣate tasmādyathaiva pūrvāsāmudarka evametāsāmiśvibhyāṃ hyevāśvinościtimanūpādadhata

They said, 'The Asvins have become everything here: with the help of the Asvins let us lay down (bricks) along with the Asvins’ layer!' With the help of the Asvins they accordingly laid down (bricks) along with the Asvins’ layer, whence they call this the Asvins’ layer. Hence the end of these (bricks) is the same as that of the former ones; for they laid them down with the help of the Asvins along with the Asvins’ layer.