THE MIAMI SERIES OF SOILS. 7 
Another area within which the altitudes are greater than 1,000 
feet lies along the southern portion of the Ohio-Indiana State line 
from near Portland, Ind., to the vicinity of Liberty. This rolling 
upland separates the drainage of the Miami River from that of the 
Whitewater River, while a branch of the same ridge lies between the 
latter stream and the eastern tributaries of the East White River. 
These ridges do not exist as distinct topographic features, but merely 
comprise the higher elevations in a rolling country between the 
principal drainage basins of southwestern Ohio and southeastern 
Indiana. With few exceptions, the local slopes and changes of ele- 
vation are very moderate. The plain merely swells to higher inter- 
stream ridges and sinks to the broad, terraced valleys of the present 
streams. 
Toward the north the plain sinks in gentle undulations to the basin 
of Lake Erie and its continuation in the broad, flat drainage system 
of the Maumee River. 
The greater part of central Indiana consists of a nearly level plain 
having a slight inclination toward the drainage basin of the Wabash 
River on the north and west and toward the course of the White 
River in the south-central part of the State. Along the Wabash 
this plain sinks to elevations of 700 to 800 feet. The southwestern 
and western borders of the region occupied by the soils of the Miami 
series do not greatly depart from the 700-foot contour line through 
much of this region. 
North of the Wabash River the region is considerably more roll- 
ing, partly, on account of the greater absolute elevation of the under- 
lying rock formations and partly because the area is dissected by 
numerous large streams which have cut comparatively deep channels. 
Beginning in extreme northeastern Indiana in the vicinity of 
Kendallville, an elevated area extends to the northeast past Hills- 
dale and Howell, Mich., to the vicinity of Lapeer. This rolling and 
ridged section has an extreme breadth of about 50 miles and lies 
chiefly above the 1,000-foot contour line. The elevation is due 
mainly to the altitude of the underlying rock which is near the sur- 
face, particularly in the vicinity of Hillsdale, and in part to the 
depth and ridgy character of the superficial glacial deposits over 
the more northern part of the ridge. From this ridge the land 
slopes to the southeast and the northwest in gently undulating or 
slightly ridged areas with intervening nearly level plains of varying 
size. 
The only other elevations in excess of 1,000 feet in the section of 
southern Michigan where the soils of the Miami series prevail occur 
along the extreme northwestern border of the area. 
