Rock formation revealed before harvest (7)
I believe the answer is:
'rock formation' is the definition.
(I've seen this before)
'revealed before harvest' is the wordplay.
'revealed' becomes 'out' (as in news which is out).
'before' says to put letters next to each other.
'harvest' becomes 'crop' (synonyms).
(Other definitions for outcrop that I've seen before include "rock appearance" , "Sudden emergence" , "Part of a rock formation above the surface" , "Cop tour around projecting layer of rock" , "Rock standing proud" .)