. Glacial formations and drainage features of the Erie and Ohio basins. heny, Pa., called Monument Hill, reaches a height ofnearly 200 feet above the river, and is separated from the north bluff by achannel less than one-half mile in widtli, in which there is a gravel fillingextending below the level of the present stream. Monument Hill appearsto be a remnant of an old gradation plain, and the river there has simplycut a double channel in its old bottom. Passing over McKees Rocks, which stand on the south side of thestream about 6 miles below Pittsburg, and seem once to have been con-nected wi
. Glacial formations and drainage features of the Erie and Ohio basins. heny, Pa., called Monument Hill, reaches a height ofnearly 200 feet above the river, and is separated from the north bluff by achannel less than one-half mile in widtli, in which there is a gravel fillingextending below the level of the present stream. Monument Hill appearsto be a remnant of an old gradation plain, and the river there has simplycut a double channel in its old bottom. Passing over McKees Rocks, which stand on the south side of thestream about 6 miles below Pittsburg, and seem once to have been con-nected with the north bluff, the next prominent rock island is oppositeSteubenville, Ohio. This island reaches a height of 450 feet above theriver, but is crossed by an old gradation plain of Harmons Creek, an easterntributary of the Ohio, which stands about 350 feet above the river. Thepresent stream occupies only the channel on the west side of the length of the island is about 2 miles, and the width is scarcely half a us. GEOLOGICAL SURVEY MO>)OGRAPH XLI PL V. TOPOdlUPHIC MAI> SHOWING I)RAINA(;E FKATlRES NEAR CINCINNATI. OHIO Contour inter^al 20 feetDatum is ftiMin. aea. U\-e/ ROCK ISLANDS IN OHIO VALLEY. 85 mile. Like Monument Hill, it is separated from the uplands east of theriver by a narrow channel, less than half a mile in average width, with agravel filling that extends down about to river level. The cause for theexcavation of a double channel at this place is not yet apparent. Opposite the mouth of Middle Island Creek, which enters the Ohio atSt. Marys, W. Va., a rock island is found on the Ohio side which standsabout 300 feet above the river. If is separated from high land on thenorth by a channel about one-third of a mile in width, whose surface isonly 50 to 60 feet above the river, and is still utilized at extreme highwater. It is probable that this island has been cut oif from the uplands onthe north by the encroachments of the Ohio River. The stream is no
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectgeology, bookyear1902
