“There is evidence to show that a considerable traffic in the finer qualities of flint and other materials desired for the manufacture of arrow- and spear-points, knives, etc., was carried on in prehistoric times with tribes in outlying and distant regions. Excursions may also have been made to points for the purpose of quarrying such stone. Thus blue and brownish hornstone appears to have found its way to Wisconsin over the trails from the quarries or deposits in Ohio and Indiana in the form of blanks, discs, and nodules. Some finished implements were probably also imported. Thousands of implements made of this hornstone are widely distributed throughout Wisconsin. The choice ivory white and pinkish flint appears to have come from Illinois or regions farther to the south. Black flints entered from the same direction. Some of the beautiful tortoiseshell-colored chalcedony so frequently employed here may have been imported from localities in Minnesota or North Dakota. A small number of obsidian implements have been recovered from mounds in southwestern Wisconsin and from fields and sites elsewhere in the state. Mr. Publius V. Lawson has published a list of some of these. “There is much yet to be learned concerning the materials, extent and direction and causes of this early inter-tribal commerce of the Upper Mississippi Valley. The present lack of a greater knowledge is largely due to the lack of state organization and intelligent coöperation on the part of archæologists and students in the outlying states of Michigan, Indiana, Illinois, Iowa, and Minnesota. [Illustration: FIG. 214_A_. (S. 1–1.) Spear-point of agate from a mound in Ramsey County, North Dakota. H. Montgomery’s collection. ]