DRAINAGE SYSTEMS AND THE GLACIAL PERIOD. 215 



some differences of opinion. Professors I. C. White and 

 J. P. Lesley, whose field work has made them perfectly 

 familiar with the upper Ohio and its tributaries, at once 

 supported the theory, with a great number of facts con- 

 cerning certain high-level terraces along the Alleghany 

 and Monongahela Rivers; while additional facts of the 

 same character have been brought to light by myself and 

 others. In general, it may be said that in numerous 

 places terraces occur at a height so closely corresponding 

 to that of the supposed dam at Cincinnati, that they cer- 

 tainly strongly suggest direct dependence upon it. The 

 upward limit of these terraces in the Monongahela River 

 is 1,065 feet, and they are found in various places in situa- 

 tions which indicate that they were formed in still water 

 of such long standing as would require an obstruction be- 

 low of considerable permanence. 



One of the most decisive cases adduced by Professor 

 White occurs near Morgantown, in West Virginia, of which 

 he gives the following description : 



"Owing to the considerable elevation— 275 feet-— of 

 the fifth terrace above the present river-bed in the vicinity 

 of Morgantown, its deposits are frequently found far in- 

 land from the Monongahela, on tributary streams. A 

 very extensive deposit of this kind occurs on a tributary 

 one mile and a half northeast of Morgantown ; and the re- 

 gion, which includes three or four square miles, is signifi- 

 cantly known as the ' Flats.' The elevation of the ' Flats ' 

 is 275 feet above the river, or 1,065 feet above tide. The 

 deposits on this area consist almost entirely of clays and 

 fine, sandy material, there being very few boulders inter- 

 mingled. The depth of the deposit is unknown, since a 

 well sunk on the land of Mr. Baker passed through alternate 

 beds of clay, fine sand, and muddy trash, to a depth of six- 

 ty-five feet without reaching bed-rock. In some portions 

 of the clays which make up this deposit, the leaves of our 

 common forest- trees are found most beautifully preserved." 



