Agniveshyagrihyasutra 3.7.3.8

3.7.3.8

yatho etadantarvedi śarīrāṇāṃ kṛṣṇājine puruṣākṛtiṃ kṛtvā teṣūpari pātrāṇi citvā kuśataruṇakaiḥ praticchādya prasiddhamupoṣeyuriti vijñāyate \

Now as to this: 'Within the altar-ground, having made a human likeness of the bodies on a black antelope skin, and having arranged the vessels on top of them, and having covered them with young shoots of kuśa grass, they should set it on fire according to established rule'—thus it is taught.