268 
The hill region occupies all land not occupied by the plain. It will be 
seen from the location and interconnection of these plains that the hill 
land is divided into two parts. One, a roughly triangular portion, has its 
apex at the meeting of the Lake and Pigeon plains and its base roughly a 
little below the southern line of township 7 south. This region is char- 
-acterized by a great number of hills rising on an average from 40 to 60 
feet above the plain. The highest part of the triangular hill land is in 
Rockport, near the junction of Lake and River plains, where the hills 
rise 120 feet above the plain. The next highest is at the junction of 
Pigeon and River plains, where the hills reach the height of 90 feet. The 
‘bordering hills are in general higher than the interior hills and the hills on 
the south and east higher than those on the west. 
The other portion of the hill land is higher and more irregular. The 
highest point measured is in the northwest quarter of the northwest quar- 
ter of section 3, township 7 south, range 6 west, where the ‘knobs’ rise 
240 feet above the mean level of the plain. It is probable that the Cen- 
terville knobs, three miles to the north, are higher. 
Pigeon Plain is naturally divided into two parts by a terrace (Fig. 
1) about 15 feet high, which begins near the point where Lake Plain 
joins Pigeon Plain and extends in a general northwesterly direction past 
Midway to Little Pigeon Creek. The plain north of this line is about 15 
feet higher than the portion south. The soil to the south is the same as 
that which covers the river bottoms; that to the north is entirely different, 
being a sort of reddish clay in some parts of the region and a very black 
peaty soil in others. This black portion is locally known as “black 
land.” Other differences between the northern and southern parts of Pig- 
eon Plain will be mentioned later. 
All the hills on the border of the triangular hill land, the hills along 
the southern boundry of the northern hill land from Grandview as far as 
the point where Lake and Pigeon plains meet, and the hills from that 
point to Little Pigeon Creek, along the line of the terrace, are covered 
with typical river bluff loess. 
The region in the interior of all the triangular hill land and for a short 
distance north of the southern boundary of the northern hill land is coy- 
ered with typical interstream loess. 
In all the plain region bounded by the loess-capped hills; that is, all 
the River Plain, Lake Plain and that portion of Pigeon Plain south of the 
terrace, except a narrow strip in a few places along the base of the hills, 
