304 COAl-PIELDS OF UNITED STATES. 
to October, 1838, about 1500 tons had been raised, 
worth 6000 dollars, at an expense of 15,000 dollars, 
and the proprietors were prosecuting the work with 
strong confidence in a successful result. The coal 
is a very pure anthracite, containing from 94 to 98 
per cent, of carbon. The gray wacke formation in 
which the Mansfield coal occurs, embraces a large 
part of Bristol and part of Plymouth counties, as 
well as a part of Rhode Island. All this space is con- 
sidered by some geologists as a coal-field, and, in- 
deed, for a distance of 30 miles on its northern side, 
coal has been found in many places. In Foxbor- 
ough, two miles from Mansfield, coal has also been 
found, but not in very large quantity. Small quan- 
tities of bituminous coal have been found in the new 
red sandstone near West Springfield, where there 
is an upward bend in the rock, which Prof. Hitch- 
cock imputes to the protrusion of a basaltic dike 
from below.* 
Anthracite Coal-fields of Pennsylvania.— No 
part of the world can boast of such inexhaustible beds 
of anthracite as the State of Pennsylvania. To use 
the language of Prof. Rogers : *' Embracing a terri- 
tory where the upper coal-bearing rocks of the great 
ancient secondary basis of the Continent terminate 
towards the east and north, the revolutions which 
have stripped other states of their treasures have 
left us in possession of some of the largest and 
most richly-supphed coal-fields of which any coun» 
try can boast. When we regard their immense ex- 
tent, comprising either the whole or a part of the area 
of 30 counties out of the 54 in the state, and the 
wide range and great thickness of many of the coal- 
seams ; and when we contemplate the amazing va- 
riety in the character of the mineral itself, showing 
every known gradation from cannel coal to anthra- 
♦ Hitchcock's Report of a re examination of the Economical 
Geology of Massachusetts. 
