THE 



AMERICAN 



JOURNAL OF SCIENCE. 



Established by BENJAMIN SILLIMAN in 1818. 

 EDITOES 



JAMES D. and EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors JOSIAII P. COOKE, GEORGE L. GOODALE 

 and JOHN TROWBRIDGE, op Cambridge. 



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



New Haven, 



Professor GEORGE F. BARKER, of Philadelphia. 





THIRD SERIES. 



YOL. XLIIL— [WHOLE NUMBER, CXLIIL] 



Nos. 253—258. 

 JANUARY TO JUNE, 1892. /? 



^?na/ Muse* 



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



1892. 



WITH XVII PLATES. 



