STONE IMPLEMENTS FROM SHORES OP LAKE MICHIGAN. 589 



stages of the flaking work. This material was placed in the museum 

 of the Northwestern University at Evanston and was arranged in a 

 series, begiuniDg with the water- worn pebble from the beach and ending 

 with the nearly completed but broken implement.' 



The present study is limited to a heretofore unnoticed group of 

 flaked products, which differ wholly from those of flint and chert, and 

 much time has been given to their collection and separation from other 

 allied phenomena. 



For a j)art of the material here described I am indebted to Mr. F. 

 H. Lyman, of Kenosha, who has been familiar with the sites of flaking 

 for many years. For cooperation in collecting the refuse I wish espe- 

 cially to acknowledge my indebtedness to Mr. W. 0. Wyman and Mr. 

 E. F. Wyman, of Evanston. 



THE TRAP FLAKE SERIES. 



The district between Waukegan and Kenosha, bordering the lake, 

 and more especially certain sites about the village of Benton, furnish 

 a numerous series of shoj) products in trap rock, comprising flaked cob- 

 blestones, flakes, and specialized forms. 



The total amount of this material from a number of sites was col- 

 lected for examination. All forms were gathered with equal care, in 

 order that the relative proportion of waste aud designed products might 

 be compared. The amount of such material is not great when compared 

 with the refuse of flaking in quarries, and it is doubtful whether the 

 use of intractable rock like trap would under any circumstances have 

 given rise to extensive quarrying. A few well-defined shops were found 

 near the beach where the refuse of shaping trap cobblestones is mixed 

 with camp-site remains. 



Thirty-two sites located along the sand ridges which extend north- 

 ward through the marsh from Benton Station to the Wisconsin State 

 line, a distance of 5 miles, have contributed material. All of the sites 

 are small, and marked usually by one hearth. In places they occur at 

 intervals of a few hundred feet. The most productive in trap refuse 

 were chosen for collecting. In addition to material found on the camp 

 sites, I have included in my studies local collections furnishing special- 

 ized forms obtained by others on these sites. 



The material. — The trap ro(;k occurs throughout the region in the 

 shape of cobblestones, varying greatly in size. In color, structure, and 

 composition it is fairly uniform when examined by ordinary methods; 

 commonly slate blue or gray when weathered; compact, crystalline, and 

 finely granular, giving a slightly uneven fracture. There is nothing 

 remarkable either in its weight or hardness. 



Subjected to light blows it readily yields a white powder, as it does 

 also to friction. It is, however, the j)ower of resistance to fracture 



'Report of Curator, museum, Northwestern University, 1884. 



