RESEARCH· ·1970·

GE·OLOGICAL SURVEY RESEA-RCH 1970
NEW DISCOVERIE'S OF PLEISTOCENE BISONS AND
PECCARIES IN COLORADO
By G. EDWARD LEWIS, Denver, Colo.
Abstt·aot.-Thrcc taxa of mnnunnls nrc recorded from Colorado
: JJ-ison ( G--igantob·ison) lat-lfrons from Snngnmon deposits
of the Cnnon City nrcn; JJ·ison (S·itnobison)? alleni? from lower
\Yisconsin deposits of the Denver area; and Platygon1ts oom,-
1H'C881t8 from upper \Visconsin deposits in Denver.
0. P. I-:Ia.y in 1924 (p. 2·75) published the thenknown
Pleistocene fauna of Colorado: "Llfylodon haTlani,
Ele1Jhas col~t'lnbi, E. in'bzJe'J·atm·, ill anLmlut ame'l·ican~tJ'In,
l!:'quus co'lnJJUcat~ls, E. la~urenti~ts, Oanwlops
h/tte7'fanensis, Ovibos ~ sp. indet., Bison bison~, B. sp.
extinct, Naenwrhed~ts ]Jalme?·i." This last genus and
species, from Crn,gin ( 1900), should be removed frmn
the list. Cragin based the species on an incomplete
humerus and an :incomplete metacarpus, both innnature,
:from a cave near Colorado Springs. Cragin's
Hgure, without scale, suggests domestic goat or sheep,
but he made no comparisons with OazJra or Ovis, and
gave no measurements.
Few additions to I-Iay's list have been recorded since
that time. Cook ( 1930, p. 68) repm~ted seeing
(• ~~ ~~ a molur tooth of a very large fossil bison, of the size
found in the immense B. lat-lj1·ons ·~ ~\ ~~ in association with
1i.Jlcphas cf. colmnbi •:• ~~ ''' [from] the mountains between Gunnison
nndl\Iontrosc, Colorado ~' ·~ ~\ The father of the young man
who * "' ·~ discovered the !Jones '' ~~ "' assured the writer that the
lnrge bison horns he found there were longer than, but not quite
so robust ns, llll immense set of B·ison latifrons horns now in the
Colorado Museum of Natural History, Denver, which were found
in the early Pleistocene of Ncbrnslm.
Neither illustrations nor n1easurements were published
because Cook himself had not seen. the "horns" (he
meant horn cores). In their work on Bison, Skinner
and J(n.isen (1947) did not record these specimens.
Now, two fragmentary horn cores of giant bison have
been found in Colorado. They confirm, in documented
form, Cook's reported occurrences of giant bison in
Colorado. Another new discovery adds the genus
Platygontts, an extinct peccary, to the known Pleistocene
fauna of Colorado.
BISON (GIGANTOBISON) LATIFRONS (Harlan), 1825
In 1967, Glenn R. Scott, of the U.S. Geological Survey,
visited the Canon City ~1useum, where he saw a
specimen, until then believed to be a mamn1oth tusk,
but which he suspected would prove to be a bison horn
core. Through the courtesy of H. 0. 'V"ood, Curator,
and D. I. Duncan, Assistant Curator of the n1useum,
the specimen was sent to n1e on July 28, 1967.
~1y report of August 23, 1967, confirmed Scott's
ten:tati ve conclusion tJlutt tJhe specimen is frmn n, bison.
11he two fragments of bone frmn tJhe gravel pit in S'¥1) 1
NElJ.t sec. 26, T. 18 S., R. 70 ,¥., Fren1ont County,
Colo., have been studied and identified. The tip of the
horn core is missing, and the proximal end was broken
off some distance frmn the burr at its base, so the
present chord length of 812 n1m (straight line across
the curve frmn proximal tip to distal tip on the joined
fragments preserved) and the present tip-to-tip length
along the lower curve of the core of 842 n1n1 are less
than the original total lengths frmn original distal tip
to proximal burr at the bm~e of the core (compare
Skinner and I(aisen, 1947, measurmnents 4 and 5, fig.
1, p. 144-145). Because of the fragmentary nature of
the core, the maximmn diameter at the burr is unknown.
The transverse diameter is 123 111m, 460 n1m
frmn .the distal end.
Skinner and ICaisen ( 1947, tables 10-19) list the
minimum, average, and maximum lengths of horn
cores along the lqwer curve (n1easurement 4) and
chord (measurement 5) of complete horn cores of the
sev:erail s.ubgenera and species of Bison. Only the complete
horn cores of B. ( Gigantobison) latij'l·ons attain
the minimum size calculated for the original, unbroken
Canon City specimen: at least 60 mm of the distal end
and at least 135 mm of the proximal end of its horn
U.S. GEOL. SURVEY PROF. PAPER 700-B, PAGES Bl37-Bl40
B137