It was a great pity I had not been more circumspect, for the boy was already too deeply steeped in those Acherontic waters.    From Wordnik.com.  [The Atlantic Monthly, Volume 05, No. 32, June, 1860] Reference

Acherontic cave, he very cunningly appropriated his torch; and it was not until the matter became serious, that he could be induced to restore it.    From Wordnik.com.  [Journal of a Visit to Constantinople and Some of the Greek Islands in the Spring and Summer of 1833] Reference

Jude was too much affected to go on talking at first; she, too, was now such a mere cluster of nerves that all initiatory power seemed to have left her, and they proceeded through the fog like Acherontic shades for a long while, without sound or gesture.    From Wordnik.com.  [Jude the Obscure] Reference