384 COLUMBIAN HISTORICAL EXPOSITION AT MADRID. 



It is certain that quartzite bowlders like those at Piney Branch woik 

 differently from jasper blocks; that some jasper specimens are coarser 

 or tougher than others; that iiovaculite from Arkansas fractures differ 

 ently from the material quarried at Flint Ridge; that the latter is finer 

 than that from the Lehigh Hills, and that all the North American jas 

 per so far noted is ill tempered and crossgrained as compared with the 

 silex of France and England, and no one has yet investigated fairly what 

 may prove a different process in the method of quarrying and working 

 obsidian. It is such considerations that make us realize that much 

 study is still needed to establish the fact that this process of proceed 

 ing from the rough &quot;turtle back,&quot; through a series of finer and thinner 

 &quot;blanks&quot; until the specialized spear, knife, scraper, or hoe was finally 

 reached, was everywhere the same in an age of stone. 



Catlin, quoted above, distinctly says that the Apaches made arrow 

 heads from selected chips shivered by indiscriminate blows of a pebble 

 hammer, a process which save for the first splintering began at the 

 stage of flaking by pressure, while the true &quot;turtle back&quot; or &quot;waster&quot; 

 is supposed to have been produced entirely by percussion. Certainly 

 no &quot;turtle back&quot; process preceded the implements from Easter Island 

 (fig. 6) or the Admiralty Island spears, the Australian gum hafted 

 blades, or indeed the &quot;teshoas&quot; above mentioned (fig. 4), though in 

 each case the unspecialized chip was a finished implement. On the other 

 hand, we may hardly hesitate to believe that the sacrificial knife oi 

 Mexico audits characteristic Solutreen duplicate from the French caves, 

 the great hoes of Tennessee, Arkansas, and the Ohio Yalley, the hoarded 

 blades of the Delaware Islands, the Hopewell Mounds, arid Mississippi, 

 were evolved through a series of rejects which all look much alike, 

 and somewhere lie upon the earth to attest the fact. 



But if we say no more than that this rude &quot;turtle back&quot; (PI. Ilia) 

 was incessantly produced by the &quot;modern&quot; Indian contemporaneously 

 with arrowheads, pottery, and polished stone weapons, we have stated 

 a very important fact, one that forbids us henceforth to assign an age 

 to these objects judged by their forms alone. This brings us to the 

 celebrated Trenton Gravel specimens, as exhibited in the University oi 

 Pennsylvania and National Museum cases. 



Figs. 14 and 1G show specimens of these &quot;turtle backs&quot; from the 

 Abbott collection in the Peabody Museum at Cambridge, Massachusetts, 

 labeled as having been found at recorded depths in the Trenton Gravel. 

 There were no Trenton specimens shown at Madrid alleged to have been 

 found geologically in place, and none of those found at the site by Dr. C. 

 C. Abbott, Prof. H. W. Haynes, Prof. Boyd Dawkins, Professors Morse 

 and Putnam have ever been photographed in place. Opinion in Amer 

 ica is divided between those who are willing to take the word and 

 experience of these gentlemen and those who are not. 



The former declare that the implements have been found at various 

 depths in undisturbed gravel, disassociated with any trace of jasper 

 arrowheads, pottery, or polished implements, and denoting, a man in 



