^/ 



THE 



AMERICAN 



JOURNAL OF SCIENCE 



EDITORS 



JAMES D. and EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors ASA GRAY, JOSIAH P. COOKE, and 

 JOHN TROWBRIDGE, of Cambridge, 



Professors H. A. NEWTON and A. E. VERRILL, of 



New Haven, 



Professor GEORGE F. BARKER, of Philadelphia. 



THIRD SERIES. 



VOL.. XXXIV.-tWHOLE NUMBER, CXXXIVJ 

 Nos. 199—204. 



JULY TO DECEMBER, 1887. 



^ 5" G / G 3 



WITH TEN PLATES. 



NEW HAVEN, CONN. : J. D. & E. S. DANA. 

 1887. 



