Deep narrow gauge (6)
I believe the answer is:
ravine
(Other definitions for ravine that I've seen before include "Steep-sided gorge" , "'Deep, steep valley (6)'" , "Deep narrow valley" , "Defile" , "Vainer in narrow gorge" .)
I believe the answer is:
ravine
(Other definitions for ravine that I've seen before include "Steep-sided gorge" , "'Deep, steep valley (6)'" , "Deep narrow valley" , "Defile" , "Vainer in narrow gorge" .)