Librarian U. S. Nat. Museum. 



VOL. XX. 



&OS 13 



DECEMBER, 1905. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE 



Editor: EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors GEORGE L. GOODALE, JOHN TROWBRIDGE, 

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



Professors ADDISON E. VERRILL, HORACE L. WELLS, 

 L. V. PIRSSON and H. E. GREGORY, of New Haven, 



Professor GEORGE E. BARKER, of Philadelphia, 

 Professor HENRY S. WILLIAMS, of Ithaca, 

 Professor JOSEPH S. AMES, of Baltimore, 

 Mr. J. S. DILLER, of Washington. 



FOURTH SERIES 

 YOL. XX— [WHOLE NUMBER, CLXX.] 

 No. 120— DECEMBER, 1905. 



WITH PLATES Xll-XY. 



NEW HAVEN, CONNECTICUT. 

 1905 



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