265 
sist of a deep red, pebbleless and structureless loam, the origin of which 
is an unsolved problem. The red loam, even upon moderate slopes, gullies 
‘apidly and has greatly facilitated the dissection of the region. 
The Wabash Plain, two miles in width, presents the usual flood plain 
features of levees and bayous. At one point, S. W. 4 of S. E. 4 of sec- 
tion 8, shale outcrops in the midst of the alluvium. Before the valley was 
filled this was an island in the river with deep water all around it. The 
valley filling in some places is SO feet deep, and consists of sand and gravel 
carried into the valley by water and floating ice. At a railroad gravel pit 
in section 36 twenty-five feet of fine gravel is exposed, with an occasional 
stratum containing enough clay to resist rain wash and cause the forma- 
tion of earth pillars two or three feet high. A terrace of coarse, roughly 
stratified gravel formerly occupied an area about one mile by one-half 
opposite the city of Terre Haute and was an island at high water. The 
town of West Terre Haute stands upon the southern half of it. The north- 
ern half has been entirely removed by the railroad companies and exca- 
vated to the level of low water in the river. The remaining surface is 
from 15 to 25 feet above the plain. 
The Sugar Creek Drainage System presents several peculiar features 
and furnishes some of the most interesting problems of the area. The 
small tributaries of the Wabash are usually of the parallel type, not com- 
bining into systems, the main streams flowing nearly at right angles to 
the Wabash. The Sugar creek system is fan-shaped, consisting of four 
principal streams which converge southward and eastward to a junction 
and pass out through a single gap upon the Wabash plain. East Little 
Sugar creek flows southward seven miles parallel with the Wabash river 
and about one mile west of the bluff. In sections 25 and 26 a nameless 
stream flows about one mile eastward, turns northward one-half mile and 
again eastward, both bends being right angles. This seems to be due to 
harder material in the stream’s course. 
Sugar Creek Lake—At the western border of the area surveyed the 
valley of Sugar creek widens abruptly from less than one-half mile to about 
a mile. Two miles below it narrows abruptly and flows for a mile through 
a gorge twenty to forty rods wide. The expansion and the narrows pre- 
sent each its own but related problem. 
The expanded portion of the valley. about one miie by two, is bounded 
on the south by a boulder clay bluff sixty feet high: on the north by lower 
