1884.] NATURAL SCIENCES OP PHILADELPHIA. 299 



"A Review of the American Species of Stromateidae," by 

 Morton W. Fordice. 



A Glacial Pebble. — Dr. Daniel G- Brinton exhibited a sup- 

 posed stone implement, obtained from the glacial drift in Butler 

 County, Ohio, sent to him by its finder, for examination. He 

 observed that, while there is no inherent improbability in such a 

 discovery — as it is quite likely that man, or at least an implement- 

 making animal, existed on this continent during the glacial 

 epoch — this particular specimen does not offer convincing evidence 

 that it is a work of art. It is a polished stone, resembling an 

 axe. Both these facts are against it. The axe type appears 

 late in the stone age, and nowhere, except in California, have 

 geologists gone so far as to put the age of polished stone so far 

 back in time as the tertiary period. In that enterprising State, 

 the men of science claim that, not merely fine, but the very finest, 

 examples of polished stone ever found in either continent are 

 exhumed, in situ originali, from gravels of the pliocene and post- 

 pliocene epochs (Foster, '• Prehistoric Races of America," p. 55). 

 This is in direct conflict with everything yet known of the older 

 stone age elsewhere. 



The present specimen illustrated anew how natural forces 

 occasionally simulate in their products the results of hand-work. 

 The criteria of the latter are, however, well-ascertained, and by 

 observing them one can scarcely be deceived in examining any 

 series of examples. 



December 30. 

 Mr. George W. Tryon, Jr., in the chair. 

 Forty-one persons present. 

 The following were ordered to be printed : — 



