the
headwaters of Green river, in Kentucky, to its northern limit, on the
Desmoines river, in Iowa, is more than five hundred miles; while its
greatest breadth across the States of Indiana, Illinois, and Missouri,
is more than four hunÂdred miles, and from its northern termination in
Iowa to its present known limits, on the Osage river, at the south, is
more than three hundred miles. This western coal field, therefore,
including the area thus occupied on both sides of the Mississippi
river, has a much greater superficial extent than the eastern coal
field, already described. Perhaps the entire area may be estimated at
one and a half that of the Alleghany coal field, or nearly one hundred
thousand square miles. Still farther to the south, in Arkansas, there
is a coal field of considerable extent, which has not yet been fully
explored; it is probably connected with the Missouri field.
There
are coal fields in Michigan, Rhode Island, and Massachusetts, Eastern
Virginia, North Carolina, near Fort Laramie, Puget's Sound, and
Bellingham Bay.
The
entire area occupied by coal measures in the United States, east of the
Rocky Mountains, is about two hundred thousand square miles.
The
quantity of bituminous and anthracite coal consumed in the United
States, may be estimated at fifteen millions of tons annually.
The
jet of Whitby, in Scotland, forms part of a thick bed of lignite found
there in the upper lias marls; it differs in this respect from the jet
worked in France and Spain, which is found in irregular veins in the
lower marls of the cretaceous series.
Cannel
coal is chiefly used in the manufacture of gas, but some of the harder
and more compact kinds are ocÂcasionally cut into various ornamental
objects, several of which were represented in the London Exhibition;
the most
