92 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



its altitude by aneroid is 975 feet, or 125 feet above the system that has 

 been traced up to this point along the Ohio. Probably it belongs to an 

 older stage of drainage development, and perhaps to a north-flowing 

 system. If the latter be true these curves in the Ohio are probably at the 

 place where an old divide has been crossed or a piracy in favor of the 

 western system had taken place. This question may perhaps be considered 

 to better advantage after features farther up the Ohio have been discussed. 

 On the ti'ibutaries which enter above Moundsville, and also along the 

 bluffs of the Ohio, rock shelves which appear to be remnants of old grada- 

 tion plains are conspicuous at much higher levels than have been noted 

 farther down the stream. The highest have an altitude of about 1,050 feet, 

 and others about 1,000 and 960 to 975 feet. The altitudes here given 

 pertain to the part • of the valley near Wheeling, just above Moundsville. 

 Farther north they become lower, being between 965 and 870 feet at the 

 mouth of Beaver River. The remnants above 1,000 feet are not so con- 

 spicuous as those at about that level or slightly lower. As the series 

 declines from south to north it seems probable that the gradation plains are 

 the product of a northward-flowing drainage line which had deepened its 

 valley to about 965 feet at Bellaire and Wheeling before reversal took 

 place. The gradation plain near these cities, which stands at about 1,000 

 feet, probably connects at the mouth of the Beaver with one standing 

 about 965 feet above tide, and at intermediate points includes the 990-foot 

 terrace on Buffalo Creek back of Wellsburg, and the 975-foot terrace on 

 the borders of the Ohio near New Cumberland, W. Va. The gradation 

 plain which stands at about 965 feet opposite Bellaire and Wheeling 

 probably connects with the 870-foot terrace at the mouth of the Beaver, 

 and includes the 960-foot ten-ace at the mouth of Short Creek and the 

 925-foot terrace at the mouth of Yellow Creek. Probably the north-flowing 

 system had cut down far enough before reversal took place to form a terrace 

 south of Wellsburg which stands at about 930 feet and a terrace of similar 

 height near the mouth of Cross Creek, south of Steubenville.^ 



' It should be remembered that nearly all of these measurements of terraces have been made 

 with a barometer, and are consequently only approximations to the real altitudes. The elevations at 

 neighboring points may differ a few feet less or a few feet more than these figures indicate. In the 

 case of the terrace in the northern part of Wheeling the writer had opportunity to compare an aneroid 

 reading with an accurate survey made for the Wheeling Terminal Railway, which has tunneled 

 beneath this terrace, and founa that the difference was fnl}' 9 or 10 feet; the altitude given by the 

 railway survey being 992 feet, and by the barometer 1,001 or 1,002 feet. 



