XOTES OX TIEE GEOLOGY 



The superficial deposits here are very thin. Along the Monongahela, terraces of 

 limited extent ai'e occasionally seen, hut along the smaller streams they are not 

 readily distinguishahle. ' - 



The rock deposits ])elong to the carl)oniferous age exclusively. In the gaps made 

 hy the C-heat river and Decker's creek near Morgantown, Ave find the sandstone, lime- 

 stone and shales of the Lower C-arboniferous, Umbralof Rogers. On these rests the 

 great conglomerate, which forms the saddle of the mountain, and which may be seen 

 beautifully curving in the gap of Decker's creek. On the fiank of Laui-el Hill the 

 coal measures begin, from which line they continue without serious interruption to 

 the western limit of the coalfield in Ohio. The district under consideration shows a 

 small anticlinal axis, parallel to Laurel Hill, which crosses the Monongahela just at 

 MorgantoAvn, and has a marked effect on the dip, reducing it frojn nearly two hundred 

 feet per mile, near the mountain, to little more than thirty feet per mile Avest of the 

 axis. As already stated. Brush Ridge, or the first sub-axis of the third basin of 

 Rogers, has little effect on the dip. ' 



THE COAL MEASURES. 



In describing the coal measures, I have thought it best to adopt the terms used in 

 the Geology of Pennsylvania and the Virginia Reports, for, though they may not have 

 been based on scientific grounds, they are most convenient for description, as the 

 rocks are here dcA^eloped. 



The LoAver Coal Group extending from the conglomerate to the Mahoning sand- 

 stone is found on the sides of the mountain, and disappears not far from its foot. It 

 contains one, or ifi some localities tAvo Avorkable seams of coal and some valuable de- 

 posits of iron ore. The LoAver Barren Group rests on the Mahoning sandstone and 

 reaches to the base of the PittsluTrgh coal. It contains a seam of coal, sometimes 

 Avorkable, scA^eral deposits of ore, and some limestone. The LTpper Coal Group 

 begins with the Pittsburgh coal, and includes the Waynesburg coal, Avith its OA^erlying 

 sandstone. It contains four beds of coal, all of large size, and an immense deposit of 

 limestone. Its eastern limit is Avithin tAVO miles of Laurel Hill, and it disappears 

 from four to five miles west from the mountain. The Upper Barren Group includes 

 all aboA''e the Waynesburg Sandstone, if I may so term it. Only a small portion is 

 seen in this district, and that only near the Avestern limit. It is dcA^eloped chiefly in 

 the second subdivision. It contains four beds of coal, two of workable thickness, but 

 all of rather poor quality. 



U P P E 11 B A E E E ISr G P O U p. 



This is composed chiefly of shales and sandstones. 'No satisfactory sections have 

 been obtained, as the hills ai'e usually rounded by ei'osion and covered Avith soil. On 



