Hazards: Bad air
Gear: Visits beyond the bat gate may require
air monitoring instruments because of bad air.
Length: 914 m (3,000 ft.)
Vertical Extent: 8 m (25 ft.)
Author: William R. Elliott
Guided Cave Tour - near the entrance of Gorman Cave
- photo Butch Fralia
Gorman Cave probably is
the most-visited noncommercial cave in Texas-a nice stroll in
large passage with a shallow stream.
Gorman, despite being familiar to many,
is a very important cave. Just a few meters from the Colorado River, it
apparently was formed in the phreatic zone. However, the cave shows evidence
of filling or near-filling with clay and gravel, after which downcutting
of the Colorado intersected and essentially drained the cave. The cave
is a resurgence for water that probably comes from nearby Clark's Branch
Well Cave, but the cave also back-floods when the river rises. Vadose modification
has occurred from both of these sources.
The entrance is quite scenic, being
located in a bluff on the west side of the Colorado River. A narrow, steep-sided
gully leads from the 5-m-wide, 3-m-high mouth to the river. The walls inside
are marked by massive calcite crystals. About 25-30 m inside is a second
entrance on the left, which has been enlarged several times by cavers.
After another 25 m one encounters a series of travertine dams and pools
in which fish are occasionally found after being washed in by the flooding
Colorado River. The cave continues in the same manner for another 100 m
with gravel floors, pools, short side passages, and travertine. One wades
through a low place, then pops into the Big Room, which is 5 to 10 m high,
5 to 10 m wide, and about 45 m long.
Formations in Gorman Cave
- photo Butch Fralia
Just beyond the Big Room is the gate.
No one may travel beyond the gate except under permit for exploration or
scientific studies. To the left is a steep slope up, which ends in the
Mouse Hole, a small room that often contains bats.
Beyond the gate, the cave narrows to
a gravel-floored tube 3 m in diameter. A hole down to the lower stream
level is soon seen, followed by Separation Lake, 70 m from the Big Room.
This lake is sometimes dry. After 25 m the cave seems to end in a breakdown
area, but several holes in the floor lead down to the stream and a narrow
squeeze ahead leads to a muddy passage. One crawls and walks through 100
m of gooey mud, passing a small maze on the way.
One is now in the area just before
"The Crack"-an upper level maze and an upward sloping side passage
where bats sometimes roost. The Crack has an upper and lower route. Both
are knee-to-waist-deep in mud and water. Beyond lies the Bat Room and thick,
fungus-covered guano. At this point many cavers begin panting from the
A steep slide from the Bat Room leads
to a T-shaped junction. To the left one goes 30 m to the lower level stream
again, a small, dangerous crawl. From the T-junction the right-hand passage
leads 25 m to another lake, then CO2 Alley. This passage is 3-5 m in diameter
and has a nice gravel floor. It meanders for about 175 m to the first sump.
After 50-60 m of water-filled passage there is a 50-m-long air-filled passage
that ends at a second sump, which has not been explored.
Despite being a relatively easy cave,
the back parts of Gorman are notorious for having "bad air." William R.
Elliott studied oxygen and carbon dioxide levels in Gorman and other caves
on several occasions. Oxygen levels at the end of the cave were as low
as 15% (20.9% is the normal atmospheric concentration) while carbon dioxide
was as high as 6%. Such conditions can cause headaches, rapid panting,
loss of judgment, joint pains, and sickness. The air gets gradually worse
from the entrance to the end, but most cavers do not notice it until they
are in the crawlways about halfway back. Even worse levels were found in
nearby Gorman Falls Cave (Bad Air Hole). Many caves in the Ellenburger
Limestone have bad air-the pit caves are the most hazardous. The
air is worse during the summer and fall and better in the winter and spring.
Some cavers report that the air in Colorado Bend caves becomes worse during
wet periods and better during dry periods. The carbon dioxide may emanate
from deep geochemical sources in the Gorman Formation (Ellenburger Group).
Groundwater and cold fronts may modulate the amount of carbon dioxide in
the caves. Further study of this phenomenon is needed.
Gorman contains a colony of cave myotis
bats, which is partially protected by an iron bat gate, installed past
the Big Room in 1992. However, bats may be found almost anyplace in the
cave. During the late spring the Big Room is a roost for a maternity colony,
so visitors are warned not to enter there at that time. The entrance area
occasionally has a few eastern pipistrelle bats. The cave also contains
many invertebrate species. The most interesting is Texanobathynella
bowmani from stream gravels, known only from Gorman Cave and Roaring
Spring, Garza County. Pale crayfish in the stream are the eyed surface
species Procambarus simulans. There are two troglobitic amphipods,
Stygobromus bifurcatus and S. russelli, and the amphipod
Caecidotea biseta. Terrestrial troglobites include the spider Cicurina
sansaba (known only from Gorman), and the millipede Cambala speobia.
During the summer, large societies of daddy longlegs harvestmen, Leiobunum
townsendii, occur on the walls of the second entrance room.
Elliott, W. R. 1986. Preliminary atmospheric
and biological observations in Gorman Cave and Gorman Falls Cave, San Saba
County, Texas. Report to Texas Parks and Wildlife Depart. 6 pp.
Elliott, W. R. 1993. Baseline cave
ecology, Colorado Bend State Park, Texas: July-November, 1993. Report to
Texas Parks and Wildlife Dept. 22 pp.
Elliott, W. R. 1994. Air monitoring
during construction of a cave gate. 1993 Natl. Cave Management Symp.
Proc., Carlsbad, New Mexico. American Cave Conservation Assoc.
Kastning, E. H., Jr. 1983. Geomorphology
and hydrogeology of the Edwards Plateau karst, central Texas. PhD diss.,
Univ. Texas, Austin. xxxi + 656 pp. + 6 pls.
Reddell, J. R. 1973. The caves of San
Saba County. Second Edition. Texas Speleol. Survey, 3(7-8):127 pp.