Śrīmad-Bhāgavatam 3.20.15

saḥit — it; aśayiṣṭalay — lay; abdhion the waters of the Causal Ocean-salileon the waters of the Causal Ocean — on the waters of the Causal Ocean; āṇḍaegg-kośaḥegg — egg; nirātmakaḥin an unconscious state — in an unconscious state; sāgrama little more than — a little more than; vaiin fact — in fact; varṣaa thousand years-sāhasrama thousand years — a thousand years; anvavātsītbecame situated — became situated; tamin the egg — in the egg; īśvaraḥthe Lord — the Lord.