CC Antya 14.84

eka-dina mahāprabhu samudre yāite
‘caṭaka’-parvata dekhilena ācambite
Word for word: 
eka-dina — one day; mahāprabhu — Śrī Caitanya Mahāprabhu; samudre yāite — while going to the sea; caṭaka-parvata — the Caṭaka-parvata sand dune; dekhilena — saw; ācambite — suddenly.
Translation: 
One day, while Śrī Caitanya Mahāprabhu was going to the sea to bathe, He suddenly saw a sand dune named Caṭaka-parvata.