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Big Manhole Cave

NM: Eddy Co.: NW¼ SW¼ SE¼ SEC 22, T24S, R24E; ca. 1280 m.


Location of Big Manhole Cave.Age. Mid/Late Wisconsin. Tom Safford, (personal oral communication), said a date from the 4-m depth of the Clay Shaft is 20,000 BP; that 24,900 BP at 5 m. His personal opinion is that the bottom at 6 m probably is about 30,000 BP.

Entrance to Big Manhole CaveGeneral Description. North of Carlsbad Caverns National Park boundary and less than 1220 m from Lechuguilla Cave. The entrance is a small opening near top center of large chamber. There is a 19-m drop to floor, where there is a chamber ca. 30 m in diameter. The floor slopes to near the edge of the dome on one side (collapse feature); otherwise fairly flat.

Fig. 1. Entrance to Big Manhole Cave. The protective gate has been constructed by the Bureau of Land Management. Photograph by Lauri L. Lear.

Discussion. Cavers during Spring 1989 were digging near one wall at the lowest area of the "flat" floor, having reached about 8-9 m in clay. They encountered bones from ca. 6-9 m. Some charcoal associated was associated. Jim Goodbar (Carlsbad BLM) brought the bones to Harris on 15 June 1989 and the material is curated at UTEP. The site was visited on 25 Mar 1993 by myself and Lauri Lear, accompanied by Jim Goodbar et al. The bones mentioned above came from the so-called Clay Shaft; this also was sampled extensively by Tom Safford. There are small bones and snails visible. Two other tests had been made by spelunkers: on talus (quickly abandoned) and the Breakdown Shaft. They also did extensive tunneling from the bottom of the Clay Shaft, including into a dry, fairly non-cemented area where there was a trove of mustelid skulls and other fossils.

Second phalanx of Bison showing effect of digestive juicesA Bison second phalanx shows signs of having been through the digestive system of a large carnivore (Fig. 2).

Fig. 2. Two views of a Bison second phalanx (UTEP 120-6; width approximately 42 mm) showing the effects of having passed through the digestive system of what must have been a large carnivore. Edges of the distal articular surfaces also show rodent tooth marks made after deposition.

Harris and Lear excavated a pit in Holocene sediments under contract with the BLM; this Holocene material is not recorded here, but was published in 2007 (Lear and Harris 2007).



Tympanuchus pallidicinctus—Lesser Prairie-chicken
Callipepla sp.—Crested Quail (?)


Marmota flaviventris—Yellow-bellied Marmot
Tamias sp.—Chipmunk
Thomomys bottae—Botta's Pocket Gopher
Lemmiscus curtatus—Sagebrush Vole
Microtus mogollonensis—Mogollon Vole
Neotoma cinerea—Bushy-tailed Woodrat
Neotoma leucodon—White-tooth Woodrat
Neotoma micropus—Southern Plains Woodrat
Onychomys leucogaster—Northern Grasshopper Mouse
Peromyscus sp.—White-footed Mice
Erethizon dorsata—American Porcupine
Lepus californicus—Black-tailed Jackrabbit
Sylvilagus audubonii—Desert Cottontail
Sylvilagus nuttallii—Mountain Cottontail
Notiosorex dalquesti—Dalquest's Shrew (Carraway 2010)
Sorex merriami—Merriam's Shrew
Sorex nanus—Dwarf Shrew
Sorex neomexicanus—New Mexican Shrew
Myotis sp.—Myotis Bats
Lynx rufus—Bobcat
Canis latrans—Coyote
Vulpes velox—Swift Fox
Mustela frenata—Long-tailed Weasel
Mustela nigripes—Black-footed Ferret
Taxidea taxus—American Badger
Mephitis mephitis—Striped Skunk
Spilogale gracilis/putorius—Spotted Skunk
Bassariscus astutus—Ringtail
Equus conversidens—Mexican Horse
Equus scotti—Scott's Horse
Camelops sp—American Camel
Hemiauchenia macrocephala—Big-headed Llama
Navahoceros fricki—Mountain Deer (? gen. et. sp.)
Odocoileus sp.—Deer
Stockoceros conklingi —Conkling's Pronghorn
Capromeryx furcifer—Matthew's Pronghorn
Bison sp.—Bison

Literature. Carraway 2010; Lear and Harris 2007.


Last Update: 6 Aug 2013