Forbidden Archeology_ The Full Unabridged Edition - Michael A. Cremo [243]
Sanford’s judgement is confirmed in a later study by two experts on the Wisconsin glaciation—A. Dreimanis of the University of Western Ontario and R. P. Goldthwait of Ohio State University. In a report titled “Wisconsin Glaciation in the Huron, Erie, and Ontario Lobes,” published by the Geological Society of America, Dreimanis and Goldthwait (1973) provided a chart showing the changing position of the ice front during the entire Wisconsin glaciation (our Table 5.2, Figure 5.8). According to Dreimanis and Goldthwait (1973, p. 81), the ice front depicted on the chart “represents the advances and retreats of the Manitoulin Island, in northern Lake Huron, is at the same latitude as the middle part of the St. Lawrence Lowlands. As can be seen from this table (after Dreimanis and Goldthwait 1973, p. 81), the ice front was well south of this region during the entire Wisconsin glaciation, except for the St. Pierre interstadial at 65,000 –70,000 years b.p. Tools found in glacial till at Sheguiandah, on Manitoulin Island, were probably made during this period or during the preceding Sangamon interglacial (Sanford 1971).
Figure 5.8. The Great Lakes region, showing Manitoulin Island, where the Sheguiandah site is located.
Ontario-Erie Lobe, including also participation of the Georgian Bay and Huron Lobes.” The latter two lobes are the ones that covered Manitoulin Island and the Sheguiandah site. From the chart and discussion supplied by Dreimanis and Goldthwait, it can be concluded that Manitoulin Island was under ice during the entire period from about 10,000 years ago back to the time of the St. Pierre interstadial, which ended about 65,000 years ago in the early Wisconsin.
Prior to the St. Pierre interstadial came the first Wisconsin ice advance, but Dreimanis and Goldthwait (1973, p. 81) said “there is no evidence that this first advance of the ice sheet reached the Great Lakes.” Thus the Sheguiandah site was habitable during and before the St. Pierre interstadial.
This brings us to the Sangamon interglacial period, which preceded the Wisconsin glaciation. According to some, the Sangamon interglacial extended from 75,000 to 100,000 years ago, while others say it extended from 75,000 to 125,000 years ago. The latter conclusion is based on the fact that the Gulf of Mexico provides fossil and other evidence for a warm climate during that period (Nilsson 1983, p. 455). So the most likely period for the manufacture of the stone tools found at Sheguiandah extends from the St. Pierre interstadial back through the Sangamon interglacial, perhaps as far back as 125,000 years ago.
Therefore, according to the view outlined by Sanford, we can envision the following series of events to account for the artifact-bearing geological formations observed at Sheguiandah. During the Sangamon interglacial or the earliest part of Wisconsin time, humans manufactured tools on and north of Manitoulin Island. As the ice sheet advanced after the St. Pierre interstadial, a proglacial lake formed in front of the glaciers. This proglacial lake, which covered the Sheguiandah site, deposited sediments. Perhaps a few tools discarded by humans traveling over the lake were incorporated into the sediments.
As the glacier advanced further toward Sheguiandah, it picked up tools, rocks, and earth. By ice rafting, some of these tools and rocks were floated a short distance into the proglacial lake and dropped, settling on top of the lacustrine sediments, which Lee found at the lowest levels