Chas. D. Walcott, 



U. S. Geological Survey. 



YOL. XXXYIII. NOVEMBER, 1889. 



Established by BENJAMIN SILLIMAN in 1818. 



THE CJD.WAZCOTf. 



AMERICAN 



JOURNAL OF SCIENCE. 



EDITORS 



JAMES D. and EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors JOSIAH P. COOKE, GEORGE L. GOODALE 

 a*d JOHN TROWBRIDGE, op Cambridge. 



Professors H. A. NEWTON and A. E. YERRILL, of 

 New Hayeist, 



Professor GEORGE F. BARKER, of Philadelphia. 



THIRD SERIES. 

 YOL. XXXYIII.— [WHOLE NUMBER, CXXXYIIL] 



No. 227.— NOVEMBER, 1889. 



NEW HA YEN, CONN. : J. D. & E. S. DANA. 

 1889. 



TUTTLE, MOREHOUSE & TAYLOR, PRINTERS, 371 STATE STREET. 



Published monthly. Six dollars per year (postage prepaid). $6.40 to foreign sub- 

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