us nuici 



Smithsonian Institution. 



^\ YOL. XII. 



DECEMBER, 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 SERIES. 



YOL. XII— [WHOLE NUMBER, CLXIL] 



No. 72.— DECEMBER, 1901. 



WITH PLATES VIII-IX. 



NEW HAVEN, CONNECTICUT. 

 1901. 





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

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