When the demigods and demons saw that Mandara Mountain had been lifted, they were enlivened and encouraged to begin churning again. The mountain rested on the back of the great tortoise, which extended for eight hundred thousand miles like a large island.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तमुत्थितं वीक्ष्य कुलाचलं पुनः समुद्यता निर्मथितुं सुरासुराः । दधार पृष्ठेन स लक्षयोजन- प्रस्तारिणा द्वीप इवापरो महान्
tamutthitaṃ vīkṣya kulācalaṃ punaḥ samudyatā nirmathituṃ surāsurāḥ | dadhāra pṛṣṭhena sa lakṣayojana- prastāriṇā dvīpa ivāparo mahān
SB 8.7.9