VOL. XLVIII SEPTEMBER, 1919. 



Established by BENJAMIN SILLIMAN in 1818. 

 THE 



AMERICAN 



I JOURNAL OF SCIENCE. 



Editor: EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors GEORGE L. GOODALE, JOHN TROWBRIDGE, 

 and WM. M. DAVIS, of Cambridge, 



Professors A. E. VERRILL, HORACE L. WELLS, CHARLES 



SCHUCHERT, L. V. PIRSSON, H. E. GREGORY, 



and HORACE S. UHLER, of New Haven, 



Professor JOSEPH S. AMES, of Baltimoj 

 Mr. J. S. DILLER, of Washington. Z^ n 



? SEP 2 



FOURTH SERIES \^0< 



VOL. XLVIII— [WHOLE NUMBER. CXCVIII] 

 No. 285— SEPTEMBER, 1919. 



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