Went by valley keeping especially to the north (7)
I believe the answer is:
elapsed
'went by' is the definition.
('elapse' can be a synonym of 'go by')
'valley keeping especially to the north' is the wordplay.
'valley' becomes 'dale' (dale is a kind of valley).
'keeping' indicates putting letters inside.
'especially' becomes 'esp' (common abbreviation).
'to the north' is a reversal indicator (in a down clue, letters go up or 'northward').
'dale' going around 'esp' is 'despale'.
'despale' written backwards gives 'ELAPSED'.
(Other definitions for elapsed that I've seen before include "Went by" , "Passed, of time" , "Pleased to have passed" , "Pleased (anag.)" , "Expired" .)