Lignite, a low-grade coal consisting of plant fragments and petrified wood, are from ancient swamps that formed along ancient streams flowing eastward from the Rocky Mountain uplift.
(a low-grade coal; consisting; of plant fragments and petrified wood) (Lignite; are; from ancient swamps) (ancient swamps; formed; L:along ancient streams) (ancient streams; flowing; eastward; from the Rocky Mountain uplift)
a low-grade coal Lignite ancient swamps ancient streams
consisting are formed flowing
of plant fragments and petrified wood
from ancient swamps
L:along ancient streams
eastward from the Rocky Mountain uplift