The chipped-stone assemblage recovered at the Cowan site includes 4602
specimens. These consist of 95 cores, 476 chipped stone tools and worked
pieces, 2121 pieces of flaking debris, and 1910 pieces of microdebitage
(flakes and shatter smaller than 1/4-inch from the flotation samples).
A great diversity of lithic raw materials are represented in the Cowan
site chipped stone assemblage. No primary bedrock sources of knappable
stone occur in this part of northwest Iowa, although various siliceous
stones are present in local gravel deposits. However, those materials
that are available from these secondary sources tend to occur either in
small and/or heavily flawed pieces or are relatively coarse-grained and
difficult to flake. Because of the generally poor knapping quality of
these locally available raw materials, the occupants of the Cowan site
relied to a great extent on non-local raw materials acquired either through
actual visits to distant source areas or through trade with neighboring
The suite of chipped stone tools recovered from the Cowan site is similar
of that seen on other Great Oasis sites. Bifacial
knives, side-notched and unnotched triangular projectile
and gravers from the site are typical and characteristic forms. These
artifacts were used in a variety of activities including hunting, butchering,
hideworking, bone tool manufacture, and woodworking.
The chipped stone assemblage from the Cowan site aptly reflects the hardships
of using a stone tool technology in a region where suitable stone is rare.
About one-quarter of the raw material used to make chipped stone tools
was gathered from local gravel sources. The bulk of the raw material in
the assemblage was imported into the site from other regions. Pennsylvanian-age
chert sources located in and around Madison County, Iowa provided the
greatest proportion of the stone used at the site. Overall, the assemblage
is intensively reduced. Cores and tools are generally small and recycling
of lithic items was common. Numerous broken and exhausted tools were converted
into bipolar cores in an effort to obtain another usable flake or two.
The people living at the Cowan site had broad-ranging contacts. Lithic
raw materials from far distant sources in Kansas, Nebraska, South Dakota,
North Dakota, eastern Wyoming, and southwest, south-central, and southeast
Iowa were recovered from the site. Whether these non-local stones were
obtained through travel or trade is not certain. However, raw materials
coming from different source areas were arriving at the site in different
forms. Winterset A/Bethany Falls A Chert from sources in south-central
Iowa was brought in an essentially unmodified form. Knife River Flint
from west-central North Dakota and Ogallala Orthoquartzite, most likely
from south-central South Dakota came to Cowan as roughed out and or finished
bifacial tools. The differing forms of these raw materials suggest that
they were supplied by different groups of people, thus strengthening the
argument for trade contacts rather than direct access through long-distance
Comparisons of the Cowan site assemblage to those recovered from other
Great Oasis sites and one Mill Creek site showed that there is potential
to learn a great deal about past patterns of inter-regional contact and
interaction. Though more information from many more sites is needed, data
derived from lithic raw material studies may someday augment impressions
about the later prehistory of the eastern Great Plains region that have
thus far been based largely on ceramics.
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