Beyond river, apes swimming, some diving (7)
I believe the answer is:
deepsea
'some diving' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'beyond river apes swimming' is the wordplay.
'beyond' is a charade indicator (letters next to each other).
'river' becomes 'dee' (River Dee).
'swimming' is an anagram indicator (letters swim around into a new order).
'apes' anagrammed gives 'psea'.
'dee' put next to 'psea' is 'DEEPSEA'.
Can you help me to learn more?
(Another definition for deepsea that I've seen is " well below the surface".)