, r Cyrus aqici, 



Librarian IT. S.Nat. Museum. 





YOL. XII. 



OCTOBER, 1901. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE 



Editor: EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors GEO. L. GOODALE, 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 SEEIES. 



YOL. XII— [WHOLE NUMBER, CLXIL] 



No. 70.— OCTOBER, 1901. 



WITH PLATES I-VI. 



NEW HAVEN, CONNECTICUT. 

 1901. 



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



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

 Union. Remittances should be made either by money orders, registered letters, 

 or bank checks (preferably on New York banks). 



