USING LANDSCAPE ARCHAEOLOGY TO IDENTIFY POTENTIAL SETTLEMENT PATTERNS ON UPLAND RIVERS: A VIEW FROM THE PECATONICA RIVER DURING THE HYPSITHERMAL

Abstract

This dissertation presents the results of a settlement pattern analysis of an upland river valley, the Pecatonica River, during the Middle Holocene when the Hypsithermal altered the climate creating a change of the vegetational regime of the Upper Midwest. This research was done to understand smaller river systems whose waterways fall completely within a larger river’s watershed, an area often overlooked when determining indigenous settlement patterns. Indigenous people lived in the uplands during the Middle Holocene but would not have the same environmental or geographical features that would be found along or near the major river. The question then becomes can the settlement pattern of the main river valleys be applied to the uplands if the features used by the people are not available. This dissertation takes a landscape archaeology approach, following multiple lines of evidence, to identify settlement patterns for indigenous populations in an upland setting of the Midwest of the United States, specifically the Pecatonica River valley, during the Middle Holocene (11,000 to 6,500 BP). This research contrasts human settlement within small river valleys located on uplands to the settlement patterns of adjacent major river valleys. This was done by determining locations of Middle Holocene sites based on a lithic analysis using the following lines of evidence: private collections, legacy archaeological collections, survey and excavation, review of previous CRM projects, and information taken from the state site files of Illinois and Wisconsin. Middle Holocene site locations, based on temporal/cultural affiliations and diagnostic lithic tools found at the sites, were analyzed using GIS to compare site locations with environmental factors to identify if a settlement pattern. The drainage system of the Pecatonica is found in Wisconsin and Illinois is bordered by three major river systems: the Wisconsin River of west-central Wisconsin, the Mississippi River, and the Rock River of north-central and west-central Illinois. The Pecatonica River flows through the “upland” areas of these larger river systems and falls within the Rock River watershed. During its short course, the river passes through a variety of landscapes: unglaciated terrain of the Driftless Region in Wisconsin, and in Illinois, areas covered in till and lake deposits from the Illinoian glaciation and areas covered by lake deposits and outwash dating to the Wisconsinan glaciation. The GIS analysis for the Pecatonica River buffer showed that the Driftless Region of Wisconsin and the glaciated prairie region of Illinois were utilized differently. It has identified that the indigenous people of the Middle Holocene recognized advantages within each area and settled or used those landscapes differently depending on where they were. Whether looking at the entire Middle Holocene or at specific archaeological cultural periods that make up the Middle Holocene, sites fell on soil associations and soil types that generally developed on forested regions in Wisconsin and a mix of prairie and forested regions in Illinois. When it came to landforms, uplands were preferred in the Wisconsin reach compared to floodplain and glacial landscapes in Illinois, where glacial landforms usually fell on uplands. The analysis of the settlement patterns of the Pecatonica River suggests that upland rivers might be considered a transitionary landform between larger river systems.