Some Montana Coal Felds. — Rowe. 371 
of these beds are found in the southeastern portion. The pro- 
ducts of these deposits as yet have not been put upon the mar- 
ket to any great extent, being used only for local domestic 
purposes. This variety of coal is easily broken when first quar- 
ried, but becomes very friable or slacks and crumbles after a 
short exposure to the air. North Dakota has a large area of 
this kind of fuel and is making it into briquets and placing it 
on the market. Montana to some degree is profiting by this 
example ; however, but very little lignite of this kind has ever 
been made or sold in the state. 
The true or best bituminous coals are • found in the less 
metamorphic Carboniferous and a small amount in the Permian. 
The poorer varieties of bituminous coal, usually non-coking, are 
found mostly in the Rocky mountain or metamorphic regions, 
and belong to the Jura-Trias and Cretaceous, while the lignite 
varieties belong to the non-metamorphic Cretaceous and Terti- 
ary formations, and peat to the more recent. Thus, if coal pros- 
pectors in Montana and other western states would look up 
a few points on general geology, much time and money could 
be saved. 
However, in highly metamorphic regions, the lignite is 
turned into semi-bituminous and bituminous coals, quite often 
into anthracite, and sometimes, when there has been an excess 
of change of strata the lignite is turned into graphite. This 
is shown to an admirable degree in the Rhode Island Carbon- 
iferous coal fields ; the western Pennsylvania fields are all bi- 
tuminous, because there has been but little change in the strata, 
while some of the eastern portions are anthracite, probably 
due to the orographic movements. 
Montana coal fields are similar in this respect to the Penn- 
sylvania fields. The eastern portion yields lignite, while the 
central mountainous metamorphic portion yields a semi-bi- 
tuminous, and bituminous, and in one or two other localities 
a small amounl of semi-anthracite coal. There is also one 
highly altered field that gives a little graphite. So far no true 
anthracite coal has been found in .Montana. 
The various counties in the slate will now be taken up with 
a brief discussion on one or two of the chief deposits in each 
county (Plate Tl. ). 
