Cumberland Bone Cave

There are a handful of notable Pleistocene "bone caves" in the Mid-Atlantic states. We've stopped at one of the classic sites already, Port Kennedy Bone Cave. Another classic site is Cumberland Bone Cave in western Maryland. Its scientific history began a few decades later than Port Kennedy, but both sites are of Irvingtonian age (between approximately 1.9 and 0.25 Ma), rather than a younger age like most Pleistocene sites, and the faunas from the two sites are often mentioned together.

Cumberland Cave is located just northwest of Cumberland, Maryland, at Corrigansville, on a limestone spur. The fossils were discovered when the cave deposits were pierced during work on the Western Maryland Railroad in the early 1910s. Today, this site is along the Potomac Heritage National Scenic Trail, on the Great Allegheny Passage. It first came to scientific attention in 1912, when the staff of the National Museum of Natural History were alerted to the find by Raymond Armbruster and George Roeder. Some significant quantity of fossils had already been destroyed by construction work by the time USNM paleontologist James W. Gidley arrived that year, but there was still quite a bit left. Gidley conducted excavations at the cave from 1912 to 1915 (Gidley and Gazin 1938). He began a series of publications, including: Gidley 1913a, describing an "eland", Taurotragus americanus (it turned out to be the shrub-ox Euceratherium, as per Gazin 1933); Gidley 1913b, an initial summary of the fauna introducing two more species, the wolf Canis armbrusteri and the bear Ursus (Euarctos) vitabilis; Gidley 1920a, a more developed summary with some photos of the discovery site; and Gidley 1920b, a description of three peccary species. Gidley passed away in 1931, coincidentally like Cope passing before finishing his work on the Port Kennedy fossils, and it fell to Charles Gazin to complete his work. Gazin completed two key works from Gidley's investigations and manuscript: Gidley and Gazin 1933 and 1938.

Excavating at Cumberland Cave, from Gidley 1920a.

Gidley and Gazin did not have a monopoly on the cave's fossils. Although the main pocket of bones was supposedly mined out during Gidley's excavations, later researchers found additional fossils higher in the cut through the cave system, including Jesuit priest Brother Nicholas Sullivan in the early 1950s, Harold Hamilton from the Carnegie Museum of Natural History in the early 1960s, and Trent Spielman for at least 25 years to at least 2006 (Norden 2006). A number of publications outside of Gidley's and Gazin's work have been produced over the years. A partial sample includes: Wetmore (1927); Patterson (1932); Hall (1936); Nicholas (1953); Handley (1958); Richmond (1963); Long (1964); Guilday and Handley (1967); White (1970); Holman (1977); Van der Meulen (1978); Guilday (1979); Brodkorb and Mourer-Chauvire (1984); Norden (2006); and Bredehoeft and Schubert (2015). This is by no means exhaustive; there are many more publications that briefly mention fossils from the cave.

The vertebrates from the cave have been thoroughly described. For brevity, and also because a lot of the scientific names have changed, I've restricting the following lists to generic descriptions.

Amphibians (after Holman 1977):
Salamanders: hellbenders, mole salamanders, newts, lungless salamanders
Anurans: toads, tree frogs, chorus frogs, green frogs, leopard frogs, wood frogs

Reptiles (after Holman 1977):
Turtles: bog turtles, box turtles, painted turtles
Lizards: fence lizards, skinks
Snakes: water snakes, garter snakes, hog-nosed snakes, ring-necked snakes, worm snakes, racers, green snakes, fox snakes, milk snakes, and rattlesnakes
The "crocodile tooth" of Gidley (1920a) and Gidley and Gazin (1933, 1938) was really the enamel cap of a bear's unerupted canine tooth (Richmond 1963).

A Cumberland Cave bear with fully erupted canines: the holotype of Ursus (Euarctos) vitabilis, USNM 7665, from Gidley (1913b) (with some text removed).

Birds (after Brodkorb and Mourer-Chauvire 1984):
Teals, eagles, grouse, turkeys, owls, jays, and the Passenger Pigeon

Mammals (after Gidley and Gazin 1933 and 1938, *additions from Guilday and Handley 1967):
Xenarthra: giant ground sloths*
"Insectivores": shrews, moles*
Rodents: groundhogs, ground squirrels, flying squirrels, regular old squirrels, pocket gophers, chipmunks, beavers, packrats/woodrats, deer mice, lemmings, voles, muskrats, jumping mice, porcupines
Lagomorphs: hares, pikas
Bats: vesper bats
Carnivorans: cats comparable to American cheetahs and lions, wolves, bears, fishers, mink, wolverines, otters, skunks, badgers
Proboscideans: mastodons
Perissodactyls: horses, tapirs
Artiodactyls: peccaries (particularly abundant), elk, deer, shrub-ox

Other:
Guilday and Handley (1967) reported fish.
Both Guilday and Handley (1967) and Norden (2006) reported snails and millipedes, and Norden (2006) also noted beetles, although these invertebrates have apparently never been described.
Norden (2006) reported plant fossils including grass stems and seeds such as acorns.

At least twenty species have been named from Cumberland Cave fossils, although the majority have been sunk into other species. The most familiar species still considered valid is probably one of the first, the wolf Canis armbrusteri (Gidley 1913b); most of the rest that are still valid are rodents, although the peccaries come in for some argument. I'll forego a list, but if someone really wants one, I can stick it in the comments.

The type specimen of Canis armbrusteri, USNM 7662, from Gidley 1913b.

Cumberland Cave was a sinkhole cave, and its fossils are a mix of things that fell in and things that lived there (owls, bats, rodents, etc.) (Norden 2006). It's one of those cave sites where we have disarticulated remains rather than whole skeletons, and for the large animals there are many broken and fractured bones, presumably due to gravity. The sinkhole passage is thought to have been an irregular chimney, with carcasses breaking up and breaking down over time as they got caught on things along the way to the bottom (Gidley and Gazin 1938). The sinkhole's size appears to have filtered out most mammals larger than a black bear; the few mastodon remains all came from juveniles (Gidley and Gazin 1938). The cave also seems to filled over a while, rather than a short time, given a mix of animals representing different climate regimes (Norden 2006). In particular, among animals in the lists that are still extant, you might notice pikas, lemmings, and wolverines. None of these are exactly ambling through western Maryland at this time, preferring Canada or high altitudes. Similarly, tapirs are only found today in more tropical climates. Interestingly, the herps are almost all known locally today (Holman 1977). Gidley and Gazin (1938) interpreted the overall fossil assemblage as representative of a wooded, well-watered environment.

While we're here considering shifting climates in the Pleistocene, this seems like a good place to address a couple of misconceptions. Just because we might call the Pleistocene the "Ice Age", that doesn't mean that there was ice everywhere, or that it was frigid the whole time. For example, in North America we can roughly approximate the maximum southern extent of the continental ice sheets for much of the landmass by the positions of the Missouri and Ohio rivers and Long Island, and of course a chunk of Wisconsin and Minnesota is famous as the "Driftless Area". Alpine caps also covered some real estate, but it's not as though there were glaciers pushing into the Gulf of Mexico. Furthermore, the Pleistocene was also a time of oscillation between glacial advance and retreat, rather than "all cold, all the time". It used to be thought that there were four major glacial episodes in the Pleistocene, but it is now known that there were at least eleven distinct episodes of some significance (this is based on geochemical evidence, glaciations themselves being difficult to date and excellent at covering the tracks of their forebearers). Between these glacial episodes the ice would retreat back to the polar regions and climate would return to something more like the present. The strength and duration of each glacial and interglacial episode also varied.

A composite mount from the cave's abundant peccary fossils, from Gidley (1920a).

References

Bredehoeft, K. E., and B. W. Schubert. 2015. A re-evaluation of the Pleistocene hellbender, Cryptobranchus guildayi. Journal of Herpetology 49(1):157–160.

Brodkorb, P., and C. Mourer-Chauvire. 1984. Pleistocene birds from Cumberland Cave, Maryland. Pages 39–43 in H. H. Genoways and M. R. Dawson, editors. Contributions in Quaternary vertebrate paleontology; a volume in memorial to John E. Guilday. Carnegie Museum of Natural History, Pittsburgh, Pennsylvania. Special Publication of the Carnegie Museum of Natural History 8.

Gazin, C. L. 1933. The status of the extinct American “eland”. Journal of Mammalogy 14(2):162–164.

Gidley, J. W. 1913a. An extinct American eland. Smithsonian Miscellaneous Collections 60(27).

Gidley, J. W. 1913b. Preliminary report on a recently discovered Pleistocene cave deposit near Cumberland, Maryland. Proceedings of the United States National Museum 46:93–102.

Gidley, J. W. 1920a. A Pleistocene cave deposit of western Maryland. Annual Report of the Smithsonian Institute for 1918:281–287.

Gidley, J. W. 1920b. Pleistocene peccaries from the Cumberland cave deposit. Proceedings of the United States National Museum 57(2324):651–678.

Gidley, J. W. and C. L. Gazin. 1933. New Mammalia in the Pleistocene fauna from Cumberland Cave. Journal of Mammalogy 14(4):343–357.

Gidley, J. W. and C. L. Gazin. 1938. The Pleistocene vertebrate fauna from Cumberland Cave, Maryland. United States National Museum Bulletin 171:1–99.

Guilday, J. E. 1979. Eastern North American Pleistocene Ochotona (Lagomorpha: Mammalia). Annals of Carnegie Museum 48:435–444.

Guilday, J. E. and C. O. Handley. 1967. A new Peromyscus (Rodentia: Cricetidae) from the Pleistocene of Maryland. Annals of the Carnegie Museum 39:91–103.

Hall, E. R. 1936. Mustelid mammals from the Pleistocene of North America with systematic notes of some recent members of the genera Mustela, Taxidea, and Mephitis. Carnegie Institution of Washington Publication 473:41–119.

Handley, C. O. 1956. Bones of mammals from West Virginia caves. American Midland Naturalist 56(1):250-256.

Holman, J. A. 1977. The Pleistocene (Kansan) herpetofauna of Cumberland Cave, Maryland. Annals of Carnegie Museum 46(11):157–172.

Long, C. A. 1964. Taxonomic status of the Pleistocene badger, Taxidea marylandica. American Midland Naturalist 72(1):176–180.

Norden, A. 2006. The Cumberland Bone Cave: a window into Maryland's past. The Maryland Natural Resource, Fall 2006:4–7.

Nicholas, G. 1953. Recent paleontological discoveries from Cumberland Bone Cave. The Scientific Monthly 76(5):301–305.

Patterson, B. 1932. Upper molars of Canis armbrusteri Gidley from Cumberland Cave, Maryland. American Journal of Science 23(136):334–336.

Richmond, N. D. 1963. Evidence against the existence of crocodiles in Virginia and Maryland during the Pleistocene. Proceedings of the Biological Society of Washington 76:65-67.

Van der Meulen, A. J. 1978. Microtus and Pitymys (Arvicolidae) from Cumberland Cave, Maryland, with a comparison of some New and Old World species. Annals of Carnegie Museum 47:101–145.

Wetmore, A. 1927. A record of the Ruffed Grouse from the Pleistocene of Maryland. The Auk 44(4):561.

White, J. A. 1970. Late Cenozoic porcupines (Mammalia, Erethizontidae) of North America. American Museum Novitates 2421.