Mammoth Cave National Park
Carlsbad Caverns National Park
Wind Cave National Park
cavern
mesocavern
Zion National Park
gour
room
aisle
Crater Lake National Park
megamine
trench
geomuseum
thrutch
gorge
hole
pithead
goldmine
diker
gold mine
postern
divide
cave
supersewer
delf
archway
Chickasaw National Recreation Area
sloot
dalles
mill
Platt National Park
rock
linear park
wellhead
macroblock
cryptodome
gripple
agraff
chimney
room of doom
excavation
grave
rock face
grotto
subterrane
puteal
driphole
subterrain
goldfield
Kenai Fjords National Park
lithocline
acequia
Rocky Mountain National Park
workface
peristalith
rhine
stonepit
wellfield
megabreccia
Bryce Canyon National Park
sump
road
earthhole
cataract
ditchdigging
lime pit
aquifer
dig
Big Bend National Park
Grand Canyon National Park
wellsite
duck
colliery
archeological site
break
heugh
cave in
paleocave
ditchlet
polylith