186 CEMENT MATERIALS AND INDUSTRY. [bull. 243. 
GREENBRIER LIMESTONE AM) ADJACENT SHALES. 
DISTRIBUTION. 
As shown on PL XV, the Greenbrier outcrops only in Allegany and 
Garrett counties. A single belt passes through the western part of 
Allegany, running about S. 30° W., and crossing the Potomac River 
at a point about midway between Westernport, Md., and Keysel 
W. Va. 
In Garrett County the Greenbrier is better shown, appearing in a 
number of belts or areas. As described in the report on Garrett: 
County, published by the Maryland geological survey, the six belts 
occurring in Garrett County are distributed as follows: 
The most easterly of these areas is situated parallel to and about one-half mile 
west of the crest of Savage and Backbone mountains. It enters the county from 
Pennsylvania one-half mile west .of the northeast corner of the county, and extends- 
in a southwesterly direction to the West Virginia line, 1 mile north of Potomac 
stone. This belt is about 45 miles long and from one-fourth to one-half mile wide. 
It occupies a valley between the Pottsville (Savage Mountain) and the Pocono (Little- 
Savage Mountain) ridges. This valley is drained at the north by the headwaters of 
Laurel Run and Savage River, and farther south by Little Savage River, Swamp 
Run, and Pine Swamp Run. Along the northern end of Backbone Mountain the* 
line of outcrop is for a large part of the way up on the mountain side, but farther 
south it occupies a series of valleys like those along Savage Mountain, but less- 
pronounced. 
The second Garrett County area extends along the eastern side of Meadow Moun- 
tain in the valleys of Red Run and Meadow Creek Run as far as the confluence of 
the latter with Deep Creek, near Thayerville. Thence it extends in the same south- 1 
westerly direction, in a similar series of valleys between Hoop Pole Ridge and then 
ridge of Pottsville rocks to the west of it, to the West Virginia line at a point about 
7 miles southwest of Oakland. This series of valleys is drained by branches of Deep j 
Creek and of Miller Run and by White Meadow Run and Rhine Creek. The lime- 
stone belt is about 37 miles long and from one-eighth to one-half mile in width. 
The third belt extends from a point near Thayerville on the one last described 
down the valley of Deep Creek to the mouth of Marsh Run, thence up the valley oi i 
Marsh Run to McHenry, thence in a westerly direction for 1 mile, where it bifurcates. 
One prong extends down the valley of Hoyes Run for about 1 mile, and then disap- 
pears under overlying formations. The other prong extends in a northwesterly 
direction through a valley to Sang Run. From here it extends down the Youghio- 
gheny River to points 1J miles north and 2h miles south of Sang Run, where it dips 
under the overlying formation. 
The fourth area extends from a point on the one last described at McHenry in a: 
north-northeasterly direction in the valley parallel to and about one-half mile west* 
of Negro Mountain as far as across the Pennsylvania line. This belt is about \l 
miles long and one-eighth of a mile wide. 
The fifth belt extends from a point on the third one, about 1 mile east of Sang Run, 
in a northerly and northeasterly direction, crossing the Pennsylvania line at Oakton. 
It occupies a sinuous line of valleys parallel to and about one-half mile east of the 
crest of Winding Ridge. The belt is about 13 miles long and one-eighth of a mile 
wide. 
The sixth area enters the county from West Virginia near Cranesville, and extends 
south along the valley occupied by Pine Swamp and Muddy Creek as far as Brown- 
ing Mill, and thence up the valley lying west of Snaggy Mountain for about 4 miles. 
Here it extends across the line into West Virginia. 
