Two materials are present in this category: The "inorganic" part of the coal substance, and is present in the form of "minerals" which remains in the coal substance by virtue of inert substances contaminating the plant material as it was being layed down in the peat swamp, and present in the form of minerals (which produce ash).
(Two materials; are; present in this category) (minerals; produce; ash) (Two materials; is; present in the form of "minerals" which remains in the coal substance by virtue of inert substances contaminating the plant material as it was being layed down in the peat swamp, and present in the form of minerals) (minerals; remains; in the coal substance; T:by virtue of inert substances) (inert substances; contaminating; the plant material; T:as it was being layed down in the peat swamp) (it; was being layed down; )
Two materials minerals Two materials minerals inert substances it
are produce is remains contaminating was being layed down
present in this category
ash
present in the form of "minerals" which remains in the coal substance by virtue of inert substances contaminating the plant material as it was being layed down in the peat swamp, and present in the form of minerals
in the coal substance T:by virtue of inert substances
the plant material T:as it was being layed down in the peat swamp