RESEARCH· ·1970·

B146
STRATIGRAPHY
age. A stratigraphic section measured at the site of the
bison horn core is as follows :
Parker section
Section measured in NE;!4 sec. 30, T. 5 S., R. 66 W.,
Arapahoe County, Colo., by Glenn R. Scott and Robert M.
Lindvall.
Thickness
Unit and description
(feet)
Modern loess (no soil) :
11. Sand, clayey, light-yellowish-brown, loose________ 1
Louviers Alluvium (upper part-late Bull Lake):
(Contains a composite of Bull Lake-Pinedale, Brady(?),
Altithermal, and late Holocene soils developed in
upper part; fig. 7.)
10. A horizon: Sand, silty, clayey, dark-brown (10YR
4/3)--------------------------------------- 1
9. Bca horizon: Sand, silty, clayey; coarse prismatic
structure; contains calcium carbonate along
column faces ______ __________ _________ ______ 2. 5
8. Cca horizon: Sand, silty, very pale brown; columnar
structure; dense concentration of calcium
carbonate in upper part_________ ____ ________ 4. 5
Louviers Alluvium (lower part early Bull Lake):
(Contains interstadial Bull Lake soil in upper part;
fig. 7 .)
7. Bca horizon: Sand, silty, brown (1 0YR 5/3), moderate
prismatic structure ___________________ -__ 1. 5
6. Cca horizon: Sand, silty, pebbly, light-yellowishbrown;
coarse columnar structure; contains concentration
of calcium carbonate__ _____________ 2. 5
5. C horizon : Sand, coarse, very pale brown, pebbly__ 1. 5
4. G (gley) horizon: Clay, silty, very pale brown;
strong prismatic structure (fig. 8); contains
mollusks. Bones found 2 ft above to 1.3 ft below
unit 4 ________________________ ------------- 1
3. C horizon: Sand, coarse, very pale brown, layered;
blocky structure; locally calcareous__ _________ _ 1
2. G horizon : Clay, silty, very pale brown; moderate
prismatic structure; locally calcareous because of
enrichment by ground water_______ __________ 1
1. G horizon: Sand, coarse to fine; contains pebbles,
cobbles, and boulders as much as 18 in. in diameter.
Sand is mostly composed of quartz, but
contains some feldspar. Contains streaks of
limonite and podlike areas stained by manganese
oxide. Torrential crossbedding. Contains bones,
including horn core of giant bison in coarser
middle part of deposit; also more rarely in upper
part. Upper 4 ft locally calcareous because of
enrichment by ground water__________________ 25±
D enver Formation (P aleocene and Cretaceous)
Our interpretation of the soils in this section is that
the lower part of the Louviers is early Bull Lake in
age and the upper part is late Bull Lake in age and
separated from the lower part by an interstadial Bull
Lake soil. The soil developed on the upper part formed
chiefly between Bull Lake and Pinedale times (fig. 7).
Fossils were found only in the lower part of the
FIGURE 7-Close view of soils developed on lower and upper parts
of the Louviers Alluvium at Parker bison locality, C, Cca,
and Bca, soil horizons; G, gley.
Louviers and include bones of mammals and shells of
mollusks. All the bones except the bison horn core were
nondiagnostic. The mollusks were first collected from
the upper of t.vo gley soils (fig. 8) in 1952 by M. R.
Mudge, Richard Van Horn, and G. R. Scott. Mudge
sent them to A. Byron Leonard, University of Kansas,
who identified 10 species as follows:
Dismts cronlchitei Newcomb,
Gymuhts parvus (Say),
H awaiia minuscula (Binney) ,
Lymncea cf. caperata Say,
L. parva Lea,
Retinella electrina (Gould),
Vallonia cyclophorella Sterki,
V . gmcilicosta Reinhardt,
P~tpilla blandi Morse, and
P. m~tscontm (Linnreus).
About the age of these mollusks, Leonard stated,
"I am uncertain about the age of this faunule, although
tentatively I judge it to be early ·wisconsinan." The
fatma is the same as the Louviers fatma of the K assler
quadrangle (Scott, 1963) except for Pupilla blandi
which was not found in the Kassler quadrangle or
ebewhere in Louviers Alluvium. P~tpilla blandi is common
in the Slocum Alluvium, where it is with other
species that suggest a much warmer climate than that