Archaic Period, 8000-500 B.C. Sigwan, Wisconsin length 6-1/4 in. This full-grooved axe is made from green porphyry. The bit is large in proportion to the entire axe. Collection History: The label on the bit is difficult to read but it appears to have been found near the Railroad Bridge over the Grand River at Sigwan (Sp.) Published: Gerber, Art, The Art Gerber Story, 2007, pg. 342, fig. 7.282 Thompson, Ben W., Who’s Who in Indian Relics, Vol. No. 6, 1984, pg. 235