COLUMBIAN HISTORICAL EXPOSITION AT MADRID. 389 



No. 16161. 



4 feet from surface. 



R, R, cut, 1878. 



No. 11752. 



Gravel of Trenton 



bluff, 7 feet. 



No.45913. 



R. R. cut, 7 feet. 



May, 1888. 



Fig. 16. (J) 



Three Trenton specimens (Abbott collection, Peabody Museum, Cambridge, Massachusetts), rude at 

 base and worked to points, resembling (though lacking the specialization of the latter) the rough- 

 base pointed forms from Europe (see .Fig. 17, a). The labels on the margin give the Museum record. 



Hy the kind permission of Dr. C. C. Abbott and Prof. F. W. Putnam. 



rig. IT. (i) 



THE THREE CHIEF TYPES FROM THE ENGLISH AND FRENCH RIVER DRIFT. 



(a) Unspecialized, resembling usual Trenton forms ; (6) specialized all round, leaf shaped ; (c) specialized at point, unworked at base. 

 By the kind permission of M. G. d Ault du Mesnil, Abbeville. 



