3 8 ROLLIN T. CHAM BERLIN 



Muck accumulated in alternation with layers of sand, as recurring 

 floods from heavy tropical storms carried coarse material before 

 them. 



To this formation No. 3 — just as in the case of formation No. 2 

 — the upland bog area contributed many bones of extinct verte- 

 brates as well as pebbles of black sandstone. At the same time 

 human bones, pottery, and bits of flint (which does not outcrop in 

 the region) were mingled with the flood-plain deposit, more or less 

 directly, it would appear, as the result of human activity. There 

 thus again came to be close assemblage of all this varied material in 

 this formation, just as there had previously been in formation No. 2. 



These conditions are interpreted as having been continued with 

 little change (except on the human side) till the present, for pebbles 

 of black sandstone and bones of extinct vertebrates are found in 

 the deposit of the present creek bed into which formation No. 3 merges. 



Two sets of evidence developed by Dr. Sellards need to be 

 explained if we are to accept the sequence of events above outlined. 

 Chemical analyses are cited as showing that the fossil human bones 

 from No. 2 are quite as well mineralized as are the associated bones 

 of the Pleistocene animals. Compared with a bone from an 

 Indian mound near Vero, the chief difference is that the bones from 

 No. 2 (human and other) have lost from 6 to 8 per cent of moisture 

 and from 9 to n per cent of volatile matter. The loss of these 

 easily eliminated constituents caused a proportionate increase in 

 the percentage of calcium and phosphoric acid. But there was, 

 in addition, an actual infiltration of silica, etc., from 0.4 to 2.9 per 

 cent, and of iron and aluminum oxides from 0.6 to 3.5 per cent. 

 While indicative of considerable age, it must be admitted that we 

 do not know how rapidly bones are thus altered in sandy river beds- 

 when the adjacent sands contain abundant iron oxide. 



A carapace of the turtle, Terrapene innoxia Hay, taken from 

 formation No. 2 complete, though it was very fragile at the time of 

 discovery, and the skull of a large wolf, Cams ayersi Sellards, are 

 taken as evidence that the bones of the vertebrates were not trans- 

 ported from some other point by the creek. The turtle carapace 

 was too fragile in the fossilized condition in which it was found to 

 admit of stream transportation, though perhaps it could have 



