Srimad Bhagavatam Canto 08, Chapter 05, Text 10

SB 8.5.10

payodhim yena nirmathya
 suranam sadhita sudha
bhramamano ’mbhasi dhrtah
 kurma-rupena mandarah
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
By churning the Ocean of Milk, Ajita produced nectar for the demigods. In the form of a tortoise, He moved here and there, carrying on His back the great mountain known as Mandara.
Srimad Bhagavatam Canto 08, Chapter 05, Text 09
Srimad Bhagavatam Canto 08, Chapter 05, Text 11-12