A clump of oil shale. Transparent background.
Keywords
clump,
oil,
shale,
transparent,
background,
rock,
pile,
heap,
stack,
formation,
cognition,
science,
fossil,
strata,
debris,
resource,
source,
bear,
flocked,
rich,
puckered,
boulder,
black,
slate,
earth,
impact,
fuel,
debris,
mining,
fragment