YOL. XXII. 



JULY, 1906. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE, 



Editor: "ED WAED S. DANA. 



ASSOCIATE EDITORS' 



Professors GEOKGE L. GOODALE, JOHN TEOWBEIDGE, 

 W. G. FAELGW and Wl. M. DAVIS, of Cambridge, 



Professors ADDISON E. YEEEILL, HOEACE L. WELLS, 

 L. V. PIESSON and H. E. GEEGOEY, of New Haven, 



Professor GEORGE ' F. BAEKEE, of Philadelphia, 

 Professor HENRY S. WILLIAMS, of Ithaca, 

 Professor JOSEPH S. AMES, of Baltimore, 

 Mr. J. S. DILLEE, of Washington. 



FOURTH SERIES 

 YOL. XXII— [WHOLE NUMBER, CLXXIL] 



No. 127— JULY, 1906. 



WITH PLATE I. 



NEW HAVEN, CONNECTICUT. 



1906 



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