The Shaligram sthala-purana (the principal narrative)
Brahma, Indra and Shiva prayed to Vishnu that he take residence as a stone-form; Vishnu declared that he would reside as Shaligram at Chakra-Tirtha (the Mukti-Kshetra). Vajrakeeta worms etch the chakra-spirals in the shilas. This is the world's only natural source of Shaligrams; black ammonite fossils ~165-400 million years old are found in the Kali Gandaki riverbed; the source lake is Damodar Kunda (in Upper Mustang ~5,400 m).
