ISGS Provides Assistance at Archeological Dig at Urbana's Founder's Park
Illinois State Geological Survey Quaternary (ISGS) geologists Steve Brown and Mike Barnhardt and geophysicist Tim Larson assisted University of Illinois archeologists and town officials in the characterization and identification of sediments and buried structures at three sites adjacent to Boneyard Creek in downtown Urbana. The location is thought to be near the site of a cabin built by one of the Urbana's founding fathers. This site is to become the location for a new city park, Founder's Park, in celebration of the Urbana's 175th anniversary.
Six boreholes (two hand-bucket augers and four PowerProbe) were advanced to depths ranging from 7.5 feet to 24 feet. The sediment encountered was identified as artificial fill of variable texture (generally from 7 to 10 feet below the land surface) overlying black, organic- and clay-rich silt (about 7 to 12 feet below the land surface) atop sand and gravel deposits. The fill is the result of many decades of construction and changing land use, as evidenced by the presence of brick, sand, and gravel incorporated into the fill. Also present at variable depths below the land surface are small pieces of slag, coal, and fine sand that may be the evidence of past industrial activities near the site. The organic-rich silt probably represents the land surface of the Boneyard Creek floodplain at the time of modern settlement. The sand and gravel appears to represent natural deposition on the floodplain by the creek, possibly in a point bar location. Cores and sediment samples collectedi from the six boreholes were examined, identified, and interpreted by the Survey geologists. Two cross sections and a brief interpretative document were prepared and presented to the archeologists.
Two of the sites were surveyed in a grid pattern using a ground-penetrating radar unit to help identify buried contacts and buried structures that may be related to both human and natural landscape activities. This survey provided real-time views of the subsurface and suggested areas for additional investigation. When processed, the radar data indicated the presence of disturbed ground at one site that possibly is related to past human activity. Radar images at the other site suggested the locations of old building foundations. Two descriptive posters of the radar work were prepared for the archeologist. Based on the preliminary drilling and geophysical work at the site, the archeologists decided to excavate in one area.