abysm
abyss
aqueduct
arroyo
bed
box canyon
breach
break
canal
canalize
canyon
carve
cavity
chamfer
channel
chap
chasm
check
chimney
chink
chisel
cleft
cleuch
clough
col
corridor
corrugate
coulee
couloir
crack
cranny
creek bed
crevasse
crevice
crimp
culvert
cut
cwm
dado
defile
dell
dike
ditch
donga
draw
dry bed
engrave
excavation
gullied
gullies
gullying
gullet
bluff
boulder
cavern
crater
creek
declivity
dune
glen
gulch
headland
ledge
precipice
ravine
ridge
rut
Sully
Tully
cully
gulley
sully