fullkk and ashley.] COAL FIELDS OF INDIANA AND ILLINOIS. 287 
LOWER COALS. 
The coals below the Petersburg bed in this quadrangle are of rela- 
tively little importance. Several of them, however, reach a thickness 
of 3 feet in places, are usually of a semiblock character, and on the 
whole are of much better quality than the Petersburg bed. On 
account of the cheapness of the coal from the latter, however, little 
attempt has been made to develop the lower beds; and as natural 
outcrops are very rare, their tracing is attended with much difficulty 
and uncertainty, and it is only in exceptional cases that their thick- 
ness and quality can be determined. While some of the coals may 
locally thicken to workable beds, it does not seem probable that they 
will be developed for at least a considerable length of time. The 
more important of the lower beds are the Ilouchin Creek, Survant, 
Velpen, Rock Creek, and Holland, although some of the still smaller 
and less persistent beds have been opened occasionally. 
Houcliin Creek coal. — This coal is one of the minor beds and lies 
between the Petersburg and Survant coals. It is exposed in the 
vicinity of Ilouchin Creek, Selvin, and Hemenway, and at other places. 
Its thickness is somewhat variable. Near Hon chin Creek, south 
of Cabel, and in the district northwest of Hemenway it has a 
thickness of 12 inches, but at the Ileming opening north of Selvin 
and elsewhere it reaches a thickness of 18 inches. It is almost invari- 
ably overlain by black, sheety, bituminous shale like that overlying 
the Petersburg coal. 
Survant coal. — This is frequently a coal of some importance, reach- 
ing a thickness of 5 feet in the hills near Gentry ville, though its 
thickness is not usually over 3 feet. It lies, on an average, about 45 
feet below the Houchin Creek coal and outcrops in the hills from near 
Velpen, southward to near Tennyson, passing near Stendal, Selvin, 
and Heilman. It is a semicoking coal, and is characteristically over- 
lain by a massive sandstone or by a light-colored shale that breaks 
into rhombs. At one point near Survant the interval is only 6 feet 
between this coal and the coal above, but as a rule the space is at 
least 30 feet. The Survant coal is probably the same as the Garrison 
coal north of Tennj^son, the Taylor coal at Selvin, the Corn coal north 
of Stendal, the Miller coal west of Pikeville, the coal under the bridge 
at Survant, and the Hollenburg coal southwest of Velpen. The table 
on page 289 includes a number of the characteristic measurements of 
this coal. 
Velpen coal. — At a distance of from 30 to 60 feet below the Survant 
coal is the Velpen coal, one of the most persistent beds in the region. 
It is frequently spoken of as "the 18-inch vein," as it maintains that 
thickness with great persistency. It is characteristically covered 
with a black, bituminous, sheety ^shale, above which there is often 
a foot or two of limestone. The interval between it and the Survant 
coal is, as far as seen, all clay shale, with the exception of the 
black shale and the limestone over the lower coal and the clay under 
