boro, Jackson County, and meanders southward along 
the bluffs into section 4, T. 11 S., R. 3 W., then south- 
westward and westward to enter the Mississippi River 
below Grand Tower. In earlier days, the Big Muddy 
continued its course southward along the bluffs. 
Present-day Otter Pond and Wolf Lake are parts of 
the old river channel. Big Muddy is an example of a 
Yazoo River type of tributary. 
The vegetation of Pine Hills is mostly deciduous 
forest. Prairie openings and one hill prairie (Evers 
1955) are found here. The toe or talus slopes of the 
bluffs are forested, as are the ravines that extend 
eastward into the bluffs. The south-facing ravine 
slopes are covered with xeric oaks and hickories and 
some prairie herbs, the north-facing slopes withmesic 
forest, including tulip tree and hard maple. The cliffs 
support few plants except scattered individuals of 
cliff brake, some species of goldenrod, especially 
Drummond’s, and red cedar. 
The brow slopes above the cliffs maintain forest 
in some places, prairie in others. Some of this prairie 
is of the typical hill type, with little bluestem the 
dominant grass, and some exists as small openings 
within the forest. The forest is a mixed deciduous 
type, with southern yellow pine and pink azalea as 
unusual species. Southern yellow pine is restricted 
in Illinois to two localities: Pine Hills and southern 
Randolph County to the north. Farkleberry is a com- 
mon shrub on the Pine Hills slopes. These slopes are 
also the type locality of Liatris scabra, a species 
of blazing star that was first described from collec- 
tions made here. 
Fig. 29.-- Bottomland swamp as seen from the bluff 
top in the Pine Hills area. 
22 
Fig. 30.— One of the coves of Horseshoe Lake. When 
this picture was taken, mosquito fern completely covered 
the surface of the cove to give the effect of a lawn rather 
than open water. 
The swamps are of interest botanically for the 
occurrence of several species that are rare in Illinois. 
Several species of duckweeds, including Wolffiella 
floridana, live in the water of this swamp, as do frog- 
bit and swamp loosestrife, the last a species more 
common much farther north. Here can also be found 
the rare grass Glyceria pallida. 
Part of Pine Hills and the adjacent swamps is 
in the Shawnee National Forest, part in the Southern 
Illinois University Biological Station, and part in 
private ownership. 
17. HORSESHOE LAKE 
Picturesque Horseshoe Lake, located south of 
Olive Branch, occupies parts of 12 sections in T. 
16 S., R. 2 W., in Alexander County. The outline of 
the lake, which somewhat resembles a horseshoe, 
possibly suggested the name. The lake was formed 
from an old meander of the Mississippi River, which 
is now several miles to the west. The east arm of the 
lake is approximately 3.75 miles long and 0.25 mile 
across. To the northwest is a mixture of small lakes 
and swamp areas. Stretching from the northwest are 
two arms. One trends southeastward, is about 2.75 
miles long and 0.25 mile across, and joins the east 
arm about 0.5 mile north of the southern extremity of 
the lake. Between this, the central arm, and the east 
arm is an island, about 2 miles long and 0.5 mile 
wide. The other arm, the western, trends southward 
for 0.5 mile, where a levee impounds the water and 
prevents its flow to the old lake bed that stretches 
on farther to the south. A dam and spillway at the 
south ends of the eastern and central arms control 
to some extent the water level of the lake. Overflow 
at the dam enters Lake Creek and flows northeastward 
into the Cache River. Runoff from the surrounding 
farmland and several small creeks to the north, in- 
cluding Pigeon Roost Creek, supply water to the lake. 
During the dry seasons, several large wells augment 
this supply. The lake and some of the surrounding 
area serve as a state wildlife refuge. 
