Very narrow lane in depressed area (6)
I believe the answer is:
valley
'depressed area' is the definition.
(geographical depression)
'very narrow lane' is the wordplay.
'very' becomes 'v' (abbreviation).
'narrow lane' becomes 'alley' (I've seen this before).
'v'+'alley'='VALLEY'
'in' is the link.
(Other definitions for valley that I've seen before include "Dale, dene or glen" , "in victory with large marble" , "Flat area of land flanked by hills" , "one depressed" , "Low area between hills" .)