408 The Upper Devonian Deposits of Maryland 



Catskill formation. On the crest of Little Savage Mountain imme- 

 diately s;icceeding in stratigraphic order the greenish zone just described 

 is one of brownish-red, very micaceous sandstone in which some small 

 openings have been made on each side of the road. It is a fairly heavy 

 bedded sandstone but with a more or less cross-bedded structure. The 

 average dip of these l)e(ls to the north of the road is about 25° S., 60° E. 



On the south side of tlie road at the summit is a ledge of brownish- 

 gray, very micaceous sandstone in which there is a small excavation. 

 Some of the layers are brownish-red and others grayish and the surface 

 of most of them is very irregular. The dip of these layers varies from 25° 

 to 27° S., 55° E. ; while in the road at the corner are dips varying from 

 24° to 28°. Just to the east of the crest and a few feet above the 

 brownish-red, micaceous sandstone is a stratum of mottled, brownish-red 

 and greenish sandstone. This is the highest stratum shown on the road 

 which could be included in the Catskill. The thickness of this brown- 

 ish-red and mottled zone at the top of the Catskill is 14 feet. 



An estimate of the thickness of the Catskill of this section (No. I) 

 was made by pacing the distance from a point near the foot of the first 

 ridge west of Mr. Johnson's to the crest of Little Savage Mountain, in a 

 direction about at right angles to the strike and averaging the various 

 observed dips which gave a thickness of nearly 1900 feet. 



Exposure on Road over Four Mile Ridge.- — ^On the steep hillside, 

 1 mile south of Avilton, are interrupted outcrops of the lower 

 part of the Catskill formation which consists largely of blocky 

 brownish-red sandstone alternating with red shale; some of the lower 

 sandstones are in thin layers and cross-bedded. The dip is between 1H° 

 and 19° S., 70° E. In the bed of Savage River thin bedded, brownish-red 

 sandstones show a dip of 17°. In the lower part of Four Mile Ridge are 

 conspicuous ledges of brownish-red sandstone, somewhat cross-bedded, 

 alternating with red, rather blocky shales. This zone is well shown along 

 the highway up the ridge and the dip varies from 18° to 20° eastward with 

 a strike N. 35° E. There are various exposures of the red shales and sand- 

 stones farther up the road with dips varying from 20° to 24° and a strike 

 of N. 35° E. The upper part of the Catskill formation is partly concealed ; 



