Valmiki Ramayana Kishkindha Kanda Sarga 42 Shloka 27

समुद्रस्य of the sea, चतुर्भागे in the one fourth part, चक्रवान् नाम Chakravan, पर्वतः mountain, तत्र there, विश्वकर्मणा by Visvakarma, सहस्रारम् thousand spiked, चक्रम् wheel, निर्मितम् constructed

'Then move to the fourth part (of the western sea) where you will see a mountain called Chakravan occupying a quarter part of the sea.You will find there a thousandspiked wheel built by Visvakarma.