Corduroy features (6)
I believe the answer is:
ridges
'corduroy features' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ridges that I've seen before include "Long, narrow ranges of hilltops" , "Wrinkles" , "Strips either side of a ploughed furrow" , "Long, narrow elevations" , "long stretches high up" .)