THE GLACIAL SUCCESSION IN OHIO. 



In Ohio, as in other portions of the Mississippi basin, clear 

 and unmistakable evidence of discontinuity in the drift deposi- 

 tion has long been recognized. Whittlesey, Newberry and 

 Orton were among the first to announce the occurrence of 

 buried soils in the North American drift, and they each drew 

 illustrations from Southwestern Ohio. A few years later Profes- 

 sor Chamberlin discovered evidences of late advances in which 

 the outline of the ice-sheet was very different from that of the 

 glacial boundary. He also observed that the aspect of the drift 

 is much fresher than in the outlying earlier drift. He further 

 noted the evidence of valley erosion of considerable amount 

 effected in the interval between the formation of two moraines, 

 or more accurately two sets of moraines, in Western Ohio, the 

 oldest of which is much younger than the earliest drift sheet, as 

 will be seen below. My own studies, carried on under the direc- 

 tion of Professor Chamberlin, have brought out more fully the 

 nature and value of these and other intervals which exist in that 

 region. No less than nine of the twelve criteria for discrimination 

 between glacial epochs set forth by Professor Salisbury in the 

 opening number of this Journal have been found, viz.: (i) 

 Buried soils. (2) Buried fossiliferous silts. (3) Differential 

 weathering. (4) Differential subaerial erosion. (5) Excava- 

 tion of valleys between successive depositions of drift. (6) 

 Changes in the course of ice-currents and in the outline of the 

 ice margin. (7) Superposition of drift of different physical 

 constitution. (8) Varying altitudes of the land. (9) Varia- 

 tions in vigor of ice action. Although the present state of 

 knowledge of the Ohio drift is far from being as complete as 

 one could desire, it seems profitable to review such evidence as 

 throws light upon the value of the several intervals which mark 

 the glacial succession in that state. In the western portion of 



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