340 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



SECTION II. EARliY WISCONSIN DRIFT OF THE SCIOTO LOBE. 



INTRODUCTORY STATEMENT. 



The Scioto lobe, as indicated iu PL XIII, covered nearly one-half of 

 the glaciated portion of Ohio, and occupied the ground between the Grand 

 River lobe on the east and the Miami lobe on the west. It was differentiated 

 into an eastern and western portion by a highland tract near Mansfield, 

 but in the former portion the lobation was slight compared with that in the 

 latter, and the striae indicate that it had not such perfect divergent movement 

 as is commonly displayed by glacial lobes. It is therefore classed as a 

 shoulder or lateral extension of the main lobw. 



The outline of this lobe and its shoulder, together with the bearing of 

 the striae, show a striking dependence upon the physical features of the 

 region, the movement being greatly extended along the axis where low 

 altitude and a smooth surface prevailed, and but slightly extended over 

 elevated and hilly districts which border the basin. A feature of much 

 significance is found in the winding course of the axial movement, which 

 shows a tendency to accommodate itself to the lowest parts of the district 

 traversed. This is well shown by the striae. In passing from the western 

 end of the Lake Erie Basin to the Scioto Basin the movement changed from 

 a southwestward to a southward course. Within the Scioto Basin the 

 movement was slightly east of south to the vicinity of Columbus, beyond 

 which it turned southwestward, there being a lower and smoother tract of 

 country in that direction than down the Scioto. At its terminus at the 

 outer moraine in Clinton and Highland counties it fronted nearly south- 

 west. This winding course of the axial movement is in accord with the 

 view that previous to the last ice invasion the topography was similar to 

 what it is now. Indeed, all the striking peculiarities of outline which this 

 glacial lobe presents — the reentrant angle at the highlands between the 

 Grand River and Scioto lobes, the shelf at the highlands near Mansfield, 

 the long lobe in the Scioto Basin, the winding course of the ice tongue 

 in passing from the Lake Erie Basin to the extremity of the lobe, and 

 the reentrant angle at the highlands between the Scioto and Miami lobes — 

 seem to be dependent upon topography that was essentially the same 

 previous to this ice invasion as it is now. No doubt considerable abra- 

 sion resulted from each of the ice invasions, but no evidence has been 



