Śatapatha Brāhmaṇa ("of a hundred paths") 13.8.1.6

13.8.1.6

athāto bhūmijoṣaṇasya udīcīnapravaṇe karotyudīcī vai manuṣyāṇām diktadenam manuṣyaloka ābhajatyetaddha vai pitaro manuṣyaloka ābhaktā bhavanti yadeṣām prajā bhavati prajā hāssya śreyasī bhavati

Now as to the choosing of the ground. He makes it on ground inclining towards the north, for the north is the region of men: he thus gives him (the deceased) a share in the world of men; and in that respect, indeed, the Fathers share in the world of men that they have offspring; and his (the deceased man's) offspring will, indeed, be more prosperous.