672 ROLLIN T. CHAM BERLIN 



in question, or else the nature of the formation was unfavorable to 

 their preservation. This, of course, is not conclusive evidence that 

 they did not then live in the region, but it greatly weakens the 

 hypothesis that bones deposited in these beds were sources of 

 supply to the creek deposit after the analogy of the black pebbles. 



Bones as well as coarser fragments of any durable material 

 should, of course, tend to become concentrated in a stream bed as 

 the finer inclosing sands are washed downstream. This is a well- 

 recognized principle and it might well account for the fact that 

 bone fragments are rare in the upland formations and numerous in 

 the creek channel deposits. But whether this selective concentra- 

 tion of coarser fragments in the channel by the action of the stream 

 is quantitatively adequate to explain the difference is questionable, 

 and it is not wise to appeal to it unless all other explanations fail. 

 The solution of the riddle of the mixture of the bones of extinct 

 animals with human bones and pottery was therefore sought on 

 other lines. 



It is true that, at a point three miles west of Vero, Dr. Sellards 

 had found the wreck of a proboscidian in a fresh-water marl deposit 

 close to the surface and referable to the general upland deposit 

 back of the beach ridge. 1 Dr. Sellards had also recognized a fauna 

 similar to that found in his formation No. 2 — the lower creek 

 deposit — in a fresh-water marl bed belonging to the upland deposit 

 at a point about 1,700 feet east of the Florida East Coast Railway 

 bridge, i.e., downstream from the deposits which contain human 

 relics. Both these facts seem to imply that a fauna of the general 

 type found in the lower creek deposit occupied the region at some 

 time during the formation of the upland deposits, and to this 

 extent they support the general correctness of the inferences enter- 

 tained in my contribution to the symposium, but they do not sup- 

 port the specific view that the bones of the lower creek deposit were 

 in any large measure derived from the lagoon, or marsh, deposit 

 of which the indurated black sand is a part. 



These facts also weaken the presumption that the relics of the 

 extinct animals really imply so great age as Middle Pleistocene. 

 Dr. Hay, who favored the view that they were closely related to 



1 Symposium, p. 55. 



