Fathomless reaches of the sea (6)
I believe the answer is:
depths
(Other definitions for depths that I've seen before include "lowest part" , "Distances down or front to back" , "Deepest or most central parts" , "obscurities" , "Deep water" .)
I believe the answer is:
depths
(Other definitions for depths that I've seen before include "lowest part" , "Distances down or front to back" , "Deepest or most central parts" , "obscurities" , "Deep water" .)