180 



tlu' iiortli li.is sc.-ircely any si.miificiuit rid.ixfs. When sand ridges occur 

 on the area they are usually not more tliau oO-oO feet high. In the dune 

 area some of the elevations will exceed 100 feet. The lower moraine of 

 the Wisconsin sheet presents a distinct ridging in plarc.'^, with a gently 

 nndnlaling surface, but the range in elevation is slight. The area lying 

 l.ctwcen the Wisconsin drift boundary and the farthest advance of the 

 early ice sheet is a Hat to gentl.V rolling surface. 



E'.vposures. wells and borir.gs show that the preglaclal surface of the 

 drift area was much eroded, and drainage lines well advanced. If the 

 surface conld be seen it would perhajjs have much tin same aiipcarance as 

 I ho surface of the driftless area. 



The unglaciated region is a thoroughly dissected i»latoau. The eleva- 

 tion ranges from 350 feet at the southwest corner, along the Ohio, to 1,147 

 feet, at Weedpatch Hill in Brown County. The hills and ridges vary 

 nuich in general characteristics, according to the geological formations. 

 Rut the greater part of the area nniy be classed as very rugged, no level 

 tracts of very large size occur, and nmch of the surface is too hilly for 

 cultivation. In general the work of the glacier in Indiana has been to 

 make the surface more level and of much greater value from an agri- 

 cultural standpoint. 



DRAINAGE. 



The drainage has been greatly influenced by the glaciers which have 

 invaded the Stsite. Many of the pregbicial valleys were filled with drift 

 and have been able to cut out only a imrt of the material, or in many 

 cases li.MVe followed new lines entirely, (ilacial water streams have done 

 nmch on the surface, but most of these lini>s are represented only by the 

 old channels, or by streams which are iusigniticant as compared with the 

 How fi'om tlu^'^^e front. In the driftless area det'i' \alle.\s, gorges and ra- 

 vines, are charm-teristic of the drainage, some of the special draiua.iif fea- 

 tures will be f>^rf!idered umler the heading of Kivers and Lakes. 



Riicrs. — All the rivers of the State have been more or less inlluenced 

 by the glacial action. In the glaciated part there is no uniformity in the 

 drainage lines: in the driftless area a section of drainage worked out in 

 detail will present ;i jiei-fect dendritic system. 



The Ohio Uiver forms the southern boundary of the State, and flows 

 in :i winding course for 351' miles. The valley of the Ohio is very nar- 



