The stone object is an ax head; there is a groove encircling the upper part of the stone where the stone was tied with sinew or rawhide to a long wooden shaft. The end of the ax head has been ground to a narrow edge. Your ax head , in the Midwest is known as Keokuk axes. The ax head has the full grooved area, there are patterns of "full" and "three quarters" grooved areas on stone ax heads and are very difficult and tedious to make. I believe the stone ax head is of the Late Archaic period, which at the time was a time of significant change in Native American cultures. The Late Archaic period had a shift in societies which transitioned to the Woodland period and many stone ax heads have been debated whether they are of the Early Woodland or Late Archaic period. DateCirca 500 B.C. - 1000 A.D. Height 5 inches Length 2.875Extra NotesCelts are similar to axes, but had the grooves with the bit perpendicular to the axis of the handle, rather then parallel, as with an ax; axes, celts, gouges, and mauls are generally considered to be woodworking tools and are often found in areas that were once forested or still retain the native tree cover. Archaeologists question the time period of grooved stone ax heads as well as their use. Attributed to the Late Archaic/Early Woodland Period