Anandakanda 1.2.101

1.2.101

pṛthivīm apsu ca tāstvagnau sa ca vāyau sa so'mbare /
melayitvā dvādaśānte sthāpayetparameśvari //

Earth into water, and that into fire, and that into wind, and that into the sky:
having merged [them], one should establish [them] at the dvādaśānta, O supreme goddess.