Dr. Cyrus Adler, 



Librarian U. S. Nat. Museum. 



VOL. X. AUGUST, 1900. 



Established by BENJAMIN SILLIMAN in 1818. 



THE 



' AMERICAN 



JOURNAL OF SCIENCE. 



Editor: EDWARD S. DANA. 



ASSOCIATE EDITORS ' . 



Professors GEO. L. ' GOODALE, JOHN TROWBRIDGE, 

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



Professors A. E. VERRILL, HENRY S. WILLIAMS, and 

 L. V. PIRSSON, of New Haven, 



Professor GEORGE F. BARKER, of Philadelphia, 



Professor H. A. ROWLAND, of Baltimore, 



Mr. J. S. DILLER, of Washington. 



FOURTH SERIES. 



YOL. X— [WHOLE NUMBER, CLX.] 



No. 56.— AUGUST, 1900. 



WITH PLATE I. 



NEW HAVEN, CONNECTICUT. 



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