)r. Cyrus Acuer, 



Librarian U. S. Nat. Museum. 



YOL. XIII. 



FEBRUARY, 1902. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE 



Editor: EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors GEO. L. GOOD ALE, JOHN TROWBRIDGE, 

 W. G/FARLOW and WM. M. DAVIS, of Cambridge, 



Professors A. E. VERRILL, HENRY S. WILLIAMS and 

 L. V. PIRSSON, of New Haven. 



Professor GEORGE F. BARKER, of Philadelphia, 



Professor JOSEPH S. AMES, of Baltimore, 



Mr. J. S. DILLER, of Washington. 



FOURTH SERIES. 



YOL. XIII— [WHOLE NUMBER, CLXIIL] 



No. 74.— FEBRUARY, 1902. 



AVITH PLATE I. 



NEW HAVEN, CONNECTICUT 



1902. 



THE TUTTLE, MOREHOUSE & TAYLOR CO., PRINTERS, 125 TEMPLE STREET. 



Published monthly. Six dollars per year, in advance. $6.40 to countries in the 

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