184 PHYSIOGRAPHY, GEOLOGY AND MINERAL RESOURCES

formation in Maryland is probably between 2000 and 3000 feet. It
has yielded a considerable fauna of trilobites, gasteropods, lamelli-
branchs and brachiopods which present close affinities with the Che-
mung forms of the north.

THE HAMPSHIRE FORMATION. —The Hampshire formation, so
called from Hampshire county, West Virginia, is found represented,
like the Jennings formation, both in the central and western portions of
the Appalachian Region, but is best developed in the western portion
of Allegany and Garrett counties, where excellent sections occur along
the Alleghany front, and may also be seen to good advantage in Jen-
nings' and Braddock's runs west of Cumberland. From these latter
points the strata dip beneath the Carboniferous rocks of the George's
Creek Valley, occurring again in a broad Y-shaped belt which extends
from northeast to southwest across Garrett county. The deposits
of the Hampshire formation consist principally of thin-bedded sand-
stones, separated by fine-grained shales, although at times the sand-
stones become thick-bedded and may merge gradually into the shales.
The shales which predominate in the upper portion of the Hampshire
formation are for the most part of a reddish color, although at times
brown or grey. The thickness of the formation somewhat exceeds
2000 feet. No fossils have as yet been obtained from the Hampshire
formation in Maryland, but the formation is undoubtedly the equiva-
lent of the Catskill of the North.

THE CARBONIFEROUS PERIOD.

The rocks of Carboniferous age are confined to the western division
of the Appalachian Region, where they largely make up the Alle-
ghany Plateau and are found in western Allegany and Garrett
counties. The formations represented are the Pocono, Greenbrier,
Mauch Chunk, Pottsville, Savage, Bayard, Fairfax and Elkgarden.

THE POCONO FORMATION. —The Pocono formation, so called from
Pocono, Pennsylvania, is the basal member of the Carboniferous
and directly overlies the Hampshire formation above described. It
occurs in a series of narrow belts which extend from northeast to
southwest through western Allegany and Garrett counties. The
Pocono formation consists mainly of hard, thin-bedded, flaggy sand-