abstract
ancient
backdrop
background
basalt
brown
cliff
cross
design
dirt
dross
earth
environment
erosion
formation
geologic
geological
geology
gray
ground
hard
layer
layered
layers
material
mineral
mining
natural
nature
nobody
old
pattern
quarry
red
rock
rough
sandstone
section
sediment
sedimentary
soil
stone
strata
surface
texture
textured
wall