The survey area includes a total distance of about two miles extending east and west of the village of Mottville along U.S. 12 in St. Joseph and Cass Counties, Michigan. The village of Mottville is located in St. Joseph County. Three alternates have been proposed by MOOT for widening the approaches and replacing the existing bridge which crosses the St. Joseph River north of Mottville (Fig. 1).
Alternate A involves relocating the bridge to a position north of the present crossing which wo~ld have the effect of straightening the approaches in each direction.
Alternate B would involve the least disturbance to the landscape, involving only replacement of the existing bridge. Alternate C would straighten the approaches by relocating the bridge to the south of its present location.
All three modifications involve expansion from 66' to 150' of the bridge approaches for about 1/2 mile east and 1 mile west of the village of Mottville. Within the village limits the existing 100' ROW will remain.
The region traversed by this project is characterized by glacial outwash deposits which lie east of the Sturgis (Ms) moraine (Martin 1955). This area of southern lower Michigan would have been open to settlement by human populations before the end of the last glacial period; a recent estimate places this date at ca. 14,SOQB.P. (Farrand 1977:75). The fact that the project involves a crossing of the St. Joseph River made it a particularly interesting one in terms of archaeological site potential. While Cass County is not well known archaeologically, the Lower St. Joseph River valley in Berrien County is known to have had extensive prehistoric occupation.