CC Madhya 20.268

sei puruṣa virajāte karena śayana
‘kāraṇābdhiśāyī’ nāma jagat-kāraṇa
Word for word: 
sei puruṣa — the Supreme Personality of Godhead; virajāte — on the border known as Virajā; karena śayana — lies down; kāraṇa-abdhi-śāyī — Kāraṇābdhiśāyī; nāma — named; jagat-kāraṇa — is the original cause of material creation.
Translation: 
“That original Personality of Godhead, named Saṅkarṣaṇa, first lies down in the river Virajā, which serves as a border between the material and the spiritual world. As Kāraṇābdhiśāyī Viṣṇu, He is the original cause of the material creation.