Lithic Raw Material Assemblage Resources at the OSA

In-State Assemblage

The In-State assemblage was revised on a structural level based on current understandings of Iowa’s bedrock geology (Figure 4). The physical samples were reorganized within drawers that represent the stratigraphic column of Iowa (Figure 5). The In-State assemblage holds 570 samples representing 75 different lithic types from 49 of Iowa’s 99 counties. The assemblage contains lithic types from the Quaternary, Pennsylvanian, Mississippian, Devonian, Silurian, and Ordovician Systems and from both primary and secondary contexts. Lithic types are arranged within geologic systems, alphabetically by county and then alphabetically by type name. The vast majority of samples have both unaltered and heat treated samples. As this web site represents raw material resources, all samples in this assemblage are collected from geologic sources only; no samples from archaeological sites are displayed on these pages.

Out-State Assemblage

The Out-State assemblage contains 318 samples representing 144 different lithic types from 21 states and one Canadian Provence. This portion of the assemblage is organized alphabetically by state with the samples from each state organized alphabetically by county. Priority efforts continue to expand the lithic raw materials from the six immediately surrounding states, which compose 60 percent of the total Out-State assemblage. Although many lithic types have both unaltered and heat treated samples, no systematic effort has yet been made to provide both.

Figure 4. Bedrock Geologic Map of Iowa 1998

Figure 4. Bedrock Geologic Map of Iowa, 1998


Figure 5. Stratigraphic Column of Iowa 1998

Figure 5. Stratigraphic Column of Iowa, 1998


Lithic Raw Material Assemblage Resources

Lithic Drawer Maps 

This section displays the physical contents of the sample drawers housed in the laboratory at OSA (Figure 6). These drawer maps represent the physical drawers holding our lithic samples. There are headings for both the In-State and Out-State assemblages. Each drawer map contains 4 rows of 6 samples each for a total of 24 samples in each drawer (Figure 7). The sample order begins in the lower left corner and proceeds up and back in a sinuous patters ending in the lower right corner, which then flows to each successive drawer. Drawers for the In-State assemblage are labeled by geologic system following the stratigraphic column of Iowa. Each box for the In-State assemblage contains the sample name, county of origin, and catalog number. Drawers for the Out-State assemblage are labeled by state with each box containing the state name, county of origin, sample name, and catalog number. Drag the cursor over the sample name and an image of that sample will appear. Click on the sample name and larger images of all the samples in that drawer will appear. The normal type labels represents samples present in the assemblage while the shadow type labels represent those presently missing. 

Figure 6. Lithic Raw Material Assemblage drawer bank.

Figure 6. Lithic Raw Material Assemblage drawer bank.


Figure 7. Individual lithic drawer matching drawer maps.

Figure 7. Individual lithic drawer matching the drawer maps.