Large, fern-like plants and trees flourished in swamps and their fossil remains form the coal beds we mine today.
(Large, fern-like plants and trees; flourished; L:in swamps) (their fossil; remains; form the coal beds) (the coal beds; mine; T:today)
Large, fern-like plants and trees their fossil the coal beds
flourished remains mine
L:in swamps
form the coal beds
T:today