VOL. XVIII.. SEPTEMBEE, 1904. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE. 



Editor: EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors GEOEGE L. GOODALE, JOHN TEOWBEIDGE, 

 W. G. FAELOW and WM. M. DAVIS, op Cambridge, 



Professors ADDISON E. VEEEILL, HOEACE L. WELLS, 

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



Professor GEOEGE E. BAEKEE, of Philadelphia, 

 Professor HENEY S. WILLIAMS, of Ithaca, 

 Professor JOSEPH S. AMES, of Baltimore, 

 Mr. J. S. DILLEE, of Washington. 



FOURTH SERIES. 



VOL. XVIII— [WHOLE NUMBER, CLXVIIL] 



No. 105.— SEPTEMBER, 1904. 



WITH PLATES V-X. 



NEW HAVEN, CONNECTICUT. 

 1904 



THE TUTTLE, MOREHOUSE. & TAYLOR CO., PRINTERS, 123 TEMPLE STREET. 



Published monthly. Six dollars per year, in advance. $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). 



