Librarian U. S. Nat. Museum. 



YOL. XX. OCTOBER, 1905. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE. 



Editor: EDWAKD S. DANA. 



ASSOCIATE EDITORS 



Professors GEOEGE L. GOODALE, JOHN TKOWBEIDGE, 

 W. G. FAKLOW and WI. M. DAVIS, of Cambridge, 



Professors ADDISON E. VERRILL, HORACE L. WELLS, 

 L. V. PIRSSON and "HE. GREGORY, of New Haven, 



Professor GEORGE F. BARKER, of Philadelphia, 

 Professor HENRY S. WILLIAMS, of Ithaca, 

 Professor JOSEPH S. AMES, of Baltimore, 

 Mr. J. S. DILLER, of Washington. 



FOURT H SERIES 

 VOL. XX— [WHOLE NUMBER, CLXX.] 



No. 118.— OCTOBER, 1905. 



WITH PLATE IX. 



***! 



tfEC 



1905 



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