﻿lee D. Walcott, 

 Office Geological Survey. 



No. 187. Vol. XXXII. JULY, 1880. 



Established by BENJAMIN SILLIMAN in 1818. 



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AMERICAN 



JOURNAL OF SCIENCE. 



EDITORS 



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Professors ASA GRAY, JOSIAH P. COOKE, and 

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

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THIRD SERIES. 



VOL. XXXII.- [WHOLE NUMBER, CXXXIIJ 



No. 187— JULY, 1886. 



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

 1886. 



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