After Buddha's death, his shadow appeared in a cave and was shown to visitors for many years. What was the name of the cave?

"According to a popular legend among the Chinese pilgrims, the Buddha left his shadow in a cave on the mountainside in Nagarahara (old capital of the Jalalabad district). This cav­ern was the abode of a destructive dragon, Naga Gopala, who was planning to destroy the kingdom for a slight offence against him when he was a shepherd in a former life. Out of compassion for the inhabitants, the Buddha came to Nagarahara from mid India and after taming the dragon, left his shadow on the wall of the Naga Gopala cave."
https://books.google.co.uk/books?id=_KLAxmR8PZAC&pg=PR13&lpg