The organic material in coal was formed from plant debris which has been layed down in a peat swamp, over many millions of years.
(The organic material in coal; was formed; from plant debris) (plant debris; has been layed down; L:in a peat swamp, over many millions of years)
The organic material in coal plant debris
was formed has been layed down
from plant debris
L:in a peat swamp, over many millions of years