Lost River - Karst Information Portal

then proceed down hill to the north towards
Tolliver Swallowhole on County Road 200W
(Figure 47).
Begin to descend the escarpment. Note the
long pediment-like toeslope to the east as the
road goes down the slope. Do not turn left at
next intersection. Proceed north on County
Road 200W down to the Mitchell Plain level.
This is a remnant area that is being actively
altered by the Lost River processes.
The Tolliver Swallowhole parking area about
0.7 miles north of intersection. Pull off onto the
east side of road, avoiding any crops. Prepare to
walk carefully through crops about 1,500 feet due
east through the fields to the dry bed. Enter the
dry bed channel and walk northwesterly about
1,000 feet to the wooded sink. If there are no
crops in the fields, is possible to walk diagonally
directly to the swallowhole, but one then misses
the dry bed. The dry bed also exhibits normal
wet-channel fluvial (river) features. NOTE:
NSS trip will not stop at Tolliver.
Tolliver Swallowhole (National
Natural Landmark)
Tolliver Swallowhole is the third major wetweather
sink of the Lost River System (Figures
50 and 51). Tolliver is developed in the upper
St. Louis and lower Ste. Genevieve, and the
Lost River chert outcrops. During dry weather
the water typically sinks east of State Road 37,
but during flood events the river sinks first at
Stein Swallowhole, and then travels 2 miles
to Turner Swallowhole, and then travels 3.75
dry-river miles west to Tolliver Swallowhole.
Tolliver Swallowhole handles all but the largest
flood volumes and is a direct entry to the
underground Lost River. The above ground
Lost River is eroded about 25 feet below the
soil-covered surface of the Mitchell Plain, and
the incised limestone river floor drops quickly
40 feet into the swallowhole. Figure 50 is a
detailed topographic map of a portion of the
dry bed, the swallowhole, and the cave passage.
Note that there is a distinct limestone channel
developed in the basal Ste. Genevieve and upper
St. Louis leading into the swallowhole, and that
channel is cut below the grade of the dry bed,
Lost River Field Trip
which continues northward (downstream) past
Tolliver Swallowhole (Figure 50). Malott placed
the Ste. Genevive-St. Louis contact at about 590
feet above sea level. Floodwaters do occasionally
overflow the swallowhole, causing water to flow
downstream to the Cul-de-Sac about 2.5 miles
to the north (which easily overflows). In big
floods, the entire Lost River is wet all the way
to the confluence of the dry bed with the Rise
channel south of Orangeville. Malott (1952)
reported the dry bed to flood on an average of
about three times a year, though periods as long
as a year or more occur in which the entire length
of the dry bed is not used. Tolliver is by far the
most spectacular and largest of the swallowholes
along the dry bed, and Malott (1952) considered
it to really be a gulf, albeit much smaller than
Wesley Chapel Gulf. A full-fledged gulf has a
flat alluviated floor, which is only partially true
at Tolliver Swallowhole.
Figure 50 shows the cave passage
connecting the swallowhole to the main
passage of underground Lost River. It is muddy
and dangerous, and is developed in cherty St.
Louis about 30 feet below the Ste. Genevieve.
The 1991 Fee survey shows that the cave
passage drops 35 feet from the bottom of the
sink, which is about 60 feet below the Mitchell
Plain surface elevation (610 to 620 feet above
sea level), placing the upstream underground
Lost River 95 to 100 feet below the surface at
an elevation of about 520 feet above sea level.
The water also resurges via a vertical rise pool
at Wesley Chapel Gulf, about 1.5 miles to the
northwest. While there is always a flow from
this rise pool, it is only during floods that the
gulf receives much water.
The fact that the dry bed of Lost River is
some 35 feet above the bottom of Tolliver
Swallowhole indicates that the dry bed
predates the swallowhole. The Lost River is
deeply incised into the Mitchell Plain, and
has a meandering pattern across the entire
surface basin reminiscent of a typical surface
stream. Moreover, in the vicinity of Tolliver
Swallowhole, there are at least two other large
but apparently (entirely or largely) abandoned
swallowholes. One of these is mentioned above
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