NATURAL SCIENCES OF PHILADELPHIA. 21 



that man and either the mastodon or the fossil elephant were con- 

 temporaneous in this State. 



The stories of the finding of bones and teeth of fossil verte- 

 brates, I)}' miners and persons not practical geologists, nor accus- 

 tomed to stud}' the geological whys and wherefores, and who do 

 not realize the necessity of close observation and discrimation of 

 the circumstances and surroundings of the relics, are not, in the 

 writer's opinion, entitled to much weight, and are very liable to 

 give false impressions; for example, in a ravine in Alameda Coun- 

 ty, the writer found a human skull in the bank, some thirty feet 

 below the surface, and apparently in the same formation where he 

 had previousl}' discovered bones and teeth of Elephas, and after- 

 ward found a lower jaw of Mastodon and molar of Elephas, but 

 upon climbing to the top of the bank, the remaining portions of 

 the human skeleton were found some eighteen inches below the 

 surface in an old Indian burial ground or rancheria. It would 

 have been an easy matter to have labelled that skull as "found 

 with bones of Elephant and Mastodon," and passed it ofi" as an- 

 other link in the chain of evidence of the contemporaneousness of 

 man and the extinct animals; or the creek in the ravine might 

 have changed its bed and the human skull been covered up by 

 detritus in close proximity with the mastodon jaw, and after 

 many years discovered by some future fossil hunter, and the re- 

 mains of the two animals assigned, without question, to the same 



age. 



One more example. Some four years since, a friend brought 

 me a remarkably well-preserved molar of a mastodon, imbedded 

 in a bowlder of conglomerate, which he had found in Alameda 

 creek. Now, suppose that tooth, instead of being placed in the 

 writer's cabinet, had been carried by a freshet on to some gravel 

 bed along the creek, and the skull of some aborigine washed out 

 of the bank above (as they often do), or some of the stone imple- 

 ments sometimes found there had been deposited in the same place. 

 Perhaps in a few hundred years or less, some antiquarian or eth- 

 nologist finding these relics in the same gravel bed might at once 

 decide tliat they were of the same age, when in fact the mastodon 

 tooth washed out of a pliocene gravel bed, miles from where it 

 was found, and it may have l)een (and probably was) separated 

 from the other parts of the skeleton, and carried by the action of 

 water perhaps hundreds of miles before it was deposited in the 

 pliocene conglomerate; or, to carry the probabilities still further, 

 the mastodon might have lived in the miocene period, and the 

 tooth washed out of a miocene rock by a pliocene river, to where 

 it was again deposited, and afterward formed a part of the con- 

 glomerate bowlder in wiiich it was found. 



The death of Dr. John Bachraan, a Correspondent of the Acad- 

 eni}', was announced. 



