SURFACE GEOLOGY. 



9 



ever, entire, as will be shown hereafter, for other agents have been in 

 action since the melting away of the glaciers, to distribute still further 

 the materials which they ground up and transported. It may be said in 

 a general way, that the glacial snatches are found over all but the south- 

 eastern third of the State of Ohio ; the limiting line running along the 

 north side of Columbiana county, thence through the center of Stark, 

 crossing the corner of Wayne, and passing diagonally through Holmes, 

 Knox, Licking, Fairfield, Pickaway, and Ross ; thence westerly through 

 the northern part of Highland, Clermont, and Hamilton, into Indiana. 

 North and west of this line glacial marks may be detected in nearly 

 every county. A great number of observations have been made upon 

 the bearing of the glacial striae by Col. Whittlesey, the members of 

 the Geological Corps, and others. From these it appears that they con- 

 stitute two systems, one of which belongs to the highlands of the water- 

 shed and the glaciated area south of this, of which the prevailing direc- 

 tion is S. 20° to 30° E., or, more accurately, from N. to S. 45° E. In some 

 exceptional cases there is locally a marked deviation from the normal 

 bearing of this system, as will be seen by reference to the map of the 

 north-eastern counties, prepared by M. C. Read, and given below. We 

 may, however, refer all these deviations to the influence of local topog- 

 raphy, and the general bearing of the ice-marks is such as to show a 

 connected ice-sheet, of which the motion was from N. 20° to 30° W., to 

 S. 20° to 30° E. That this movement of the ice was from the north 

 southward, is demonstrated by the transportation of northern rocks into 

 and through our State, and of blocks and fragments of indigenous rocks 

 southward of their points of outcrop. 



The second system of grooves is confined to the lake-basin and the 

 north-western counties of the State. The direction of these grooves — 

 which are remarkably deep and continuous — will be seen from the sub- 

 joined table : 



DIRECTION OF GROOVES. 



Locality. 



Put-in-Bay Island (Newberry) 



" intersecting series 

 Kelley's Island (Newberry) 



Sandusk'y City 



Bellville, Sandusky county " 

 Genoa, Ottawa county (Gilbert) 



Eook. 



Waterlime 



it 



Corniferous limestone.. 



it u 



it u 



tt it 



it tt 



a tl 



Waterlime 



" and Niagara, 



Udmbek Ob- 

 servations. 



20 

 1 



12 

 1 

 4 

 2 

 1 

 1 

 1 

 2 



Bearing. 



8. 80° W. 

 S. 15° W. 

 S. 80° W. 

 S. 60° W. 

 S. 78° W. 

 S. 80° W. 

 S. 81° W. 

 S. 75° W. 

 S. 65° W. 

 8. 65° W. 



