﻿Charles D. Walcott, 



Office Geological Survey , 



No. 191. Vol. XXXII. NOVEMBER, 1886 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



AMERICAN 



JOURNAL OF SCIENCE. 



EDITORS 



JAMES D. and EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors ASA GRAY, JOSIAH P. COOKE, and 

 JOHN TROWBRIDGE, of Cambridge, 



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

 New Haven, 



Professor GEORGE F. BARKER, of Philadelphia. 



THIRD SERIES. 



VOL. XXXII. -[WHOLE NUMBER, 0XXX1IJ 



No. 191— NOVEMBER, 1886. 



NEW HAVEN, CONN. : J. D. & E. S. DANA. 

 1886. 



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



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