Dr. Cyrus Adler, 



Librarian U. S. Nat. Museum. 



VOL. XXI. 



S"0£.73 



JUNE, 1906. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE. 



Editor: EDWABD S. DANA. 



ASSOCIATE EDITORS 



Professors GEOEGE L. GOODALE, JOHN TEOWBELDGE, 

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



Professors ADDISON E. VEEEILL, HOEACE L. WELLS, 

 L. V. PIES SON and H. E. GEEGOEY, of New Haven, 



Professor GEOEGE F. BAEKEE, of Philadelphia, 

 Professor HENET S. WILLIAMS, of Ithaca, 

 Professor JOSEPH S. AMES, of Baltimore, 

 Mr. J. S. DILLEE, of Washington. 



FOURTH SERIES 

 YOL. XXI— [WHOLE NUMBEK, CLXXL] 



No. 126— JUNE, 1906. 



NEW HAVEN, CONNECTICUT. 

 1 906 



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