'O Muse, o alto ingegno, or m' aiutate;
O mente, che scrivesti ciò ch' io vidi,
Qui si parrà la tua nobilitate.'
This Cary thus translates:—
'O Muses! O high genius, now vouchsafe
Your aid. O mind, that all I saw hast kept
Safe in a written record, here thy worth
And eminent endowments come to proof.'
Hence ye in l. 520 answers to Dante's Muse, the Muses; and Thought in l. 523 answers to Dante's mente, Cf. also Parad. xviii. 82-87. And see the parallel passage in Anelida, 15-19.
The reason why Chaucer took Helicon to be a well rather than a mountain is because Dante's allusion to it is dubiously worded; see Purg. xxix. 40.