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YOL. XXXYII. JANUARY, 1914. 



Established by BENJAMIN SIILIMAN in 1818. 



THE 



AMERICAN- 



JOURNAL OF SCIENCE. 



Editor: EDWAED S. DANA. 



ASSOCIATE EDITOES 



Professors GEOEGE L. GOODALE, JOHN TEOWBEIDGE, 

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



Professors ADDISON E. VEEEILL, HOEACE L. WELLS, 



LOUIS Y PIES SON, HEEBEET E. GEEGOEY 



and HOEACE S. UHLEE, of New Haven, 



Professor HENEY S. WILLIAMS, of Ithaca, 



Professor JOSEPH S. AMES, of Baltimore, 



Mr. J. S. DILLEE, of Washington. 



FOURTH SERIES 



YOL. XXXYII— [WHOLE NUMBER, CLXXXYIIJ. 

 No. 217— JANUARY, 1914. 



WITH PLATES I-IV. 



NEW HAVEN, CONNECTICUT. 



1914. 



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



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