270 



SCIENCU. 



[Vol. I., No. 10. 



accumulation (which Dr. Newberrj' calls ' the 

 grist ' of the continental ice-sheet) is about 

 sixty feet ; though in places at the very border, 

 as at Adelphi, in Ross count}-, it is two hun- 

 dred feet. Granite bowlders from northern 

 Canada are found all the way down to this 

 limit, but not bej'ond it. There is a granite 

 bowlder at Lancaster 18 x 12 x 6 feet. The 

 glaciated portion of Ohio is level, and univer- 



crop-reports show that the average production 

 of wheat per acre is nearlj' twice as large in 

 the glaciated as in the unglaciated portion of 

 the state. 



Professor Wright's investiga- 

 tions full}' confirm the surmise 

 of Professor Shaler, that, 

 during its greatest 

 extent, the 



sally fertile. This is in part owing to the di- 

 versity of rocks ground up by the advancing 

 ice, and in part to the fact that it was pul- 

 verized bj' mechanical action, and is spread 

 evenly over the surface. South of the line the 

 country is cut up into gorges ; and, as a rule, 

 the soil is shallow and comparativelj' sterile. 

 Scratched stones are entirely absent, and gran- 

 ite is found only in the river-valleys. The 



MAP SHOWING THE COURSE OF 

 THE TERMINAL 

 or THE GLACIATED AREA OP 

 OHIO. 



ice of the glacial period 

 crossed the Ohio Eiver at Cin- 

 cinnati, and extended a few 

 miles south. From this, some 

 interesting conclusions follow. 

 The Ohio River, through its 

 entire course, occupies a valley 

 of erosion, having, for more 

 than a thousand miles, cut a gorge from three 

 hundred to five hundred feet deep through the 

 horizontal strata of the coal-formation. Dur- 

 ing the extension of the glacier into Kentuckj', 

 this caiion of the Ohio must have been filled 

 with ice at Cincinnati, forming a barrier in the 



