j£ 





I 



THE 



AMERICAN 



JOURNAL OF SCIENCE. 



Editor: EDWARD S. DANA. 



ASSOCIATE EDITOES 



Peofessoes GEO. L. GOODALE, JOHN TROWBRIDGE, 

 H. P. BOWDITCH and W. G. FARLOW, of Cahbeidge, 



Peofessoes O. C. MARSH, A. E. VERRILL and H. S. 

 WILLIAMS, of New Haven, 



Peofessoe GEORGE F. BARKER, of Philadelphia, 

 Peofessoe H. A. ROWLAND, of Baltimoee, 

 Me. J. S. DILLER, of Washington. 



FOURTH SERIES. 

 VOL. IV— [WHOLE NUMBER, CLIV] 



WITH XII PLATES. 



NEW HAVEN, CONNECTICUT. 



1897. 



