EXPLANATION OF PLATE 54. 



Unilateral Knives. 

 Fig. 1. Yeli.ow Flint. 



(Cat. No. 10821, I^.S.X.M. ISahala Creek, Copiah County, Missi-ssipjii. T. J. K. Keenan.) 



Fig. 2. Brown Chkht. 



(Cat. No. 60597, U.S.N.M. Lincoln County ( ? ), Tennessee. C. S. Gri.sl.y.) 



Fin. '^. Chert. 



(Cat. No. 34863, U.S.N.M. Falmouth Island, in Susquehanna liiver. Pennsylvania. 

 J. Orendoif and F. G. Gailbraith.) 



Fig. 4. Dark-Gray Flint. 



(Cat. No. 7672, U.S.N.M. Groveport, Ohio. W. R. Limport.) 



Fig. ."1. Mottled-Gray Flint. 



(Cat. No. 23265, U.S.N.M. Mound on i;to\\-ah River, Georgia. li. W. Gideon.) 



