404 The Uppkk Devoxiax Deposits of Marylaxd 



red shales ai'e occasional thin hands of hluish to greenish shale from a 

 fraction of an inch to an inch or more in thickness ; while at the western 

 end of the cut are some greenish-gray rather shaly sandstones. The 

 average dip of the Pocono sandstones at the eastern end of the cut is 50° 

 which gives an average dip for this zone of 51°. Horizontal distance is 

 1066 feet which gives 832 feet for the thickness of the zone. The sum 

 of these five zones gives 2327 feet as the thickness of the Catskill for- 

 mation. This, however, is too great for there are some curves on the road 

 and the horizontal distance is not a straight line. 



From the base of the second zone, the distance was paced to the base 

 of the Pocono sandstone, avoiding as much as possible the curves in the 

 road, and this gave a horizontal distance of 2175 feet; while the distance 

 determined from the raihoad rails is 2386 feet. The average dip for this 

 distance is 59i/2° which would give a thickness of 1870 feet which, plus 

 the 327 feet of the first zone makes a thickness of 2197 feet for the 

 foraiation. This is only 162 feet greater than the thickness obtained for 

 the Catskill formation in Jennings Run and is probably not seriously 

 in error. 



Exposures in Garrett County 



Exposures at Frankville and Crabtree Creel-. — Frankville is a station on 

 the Baltimore and Ohio Railroad 8 miles northwest of Piedmont. The 

 railroad follows the western side of Back Bone Mountain up Crabtree 

 Creek until the divide between the creek and the Little Youghiogheny 

 Elver is reached in the vicinity of Altamont where the liighest point of 

 the Baltimore and Ohio Eailroad, 2620 feet A. T., occurs and between 

 Frankville and this locality there are numerous cuts on the railroad, 

 affording an excellent opportunity for the examination of the Catskill 

 fonnation. The prevailing color of the rocks along the track for 2 miles 

 above Frankville is red, and they consist mainly of shales and sandstones, 

 the shales predominating. There are, however, in places some pure argil- 

 laceous shales of olive color which weather to a slightly buff tint and some 

 that are rather arenaceous. In one of these zones, perhaps one-half mile 

 above Frankville, part of a pelecypod shell was found. There is also 

 occasionally a calcareous stratum which is a sort of cornstone. Tlie 



