The bottom of the lagoon is known as Neptune's cradle.
6 seconds sound clip from the The Loved One (1965) movie soundboard.
You can hear this line at 00:41:11 in the Blu-ray version of the movie.
Quote context
[...]
- And here we have the falls of Xanadu.
- The Falls of Xanadu? Funny that Coleridge never mentioned them.
- Coleridge, the man who wrote the poem.
- I never heard there was a poem.
- All the names in Whispering Glades were created by the blessed reverend.
- The bottom of the lagoon is known as Neptune's cradle.
- Several plots are available here in the shadow of the prominent Greek poet homer.
- Yes. I think Uncle Francis would like that.
- Homer used very visual imagery.
[...]