yjl.llA.k3- IS. TT UlXK^KJlllj. 



U. S. Geol. Survey. 



VOL. "TIL 



APRIL, 1890 



Established by BENJAMIN SILLIMAN in 1818, 



THE 



AMERICAN 



JOURNAL OF SCIENCE. 



Editor: EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors GEO. L. GOOD ALE, JOHN TROWBRIDGE, 

 H. P. BOWDITCH and W. G. FARLOW, of Cambridge, 



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

 of New Haven, 



Professor GEORGE F. BARKER, of Philadelphia, 

 Professor H. A. ROWLAND, of Baltimore, 

 Mr. J. S. DILLER, of Washington. 



FOURTH SERIES. 

 VOL. YII— [WHOLE NUMBER, CLVIL] 



No. 40.— APRIL, 1899. 



WITH PLATES VI-VII. 



NEW HAYEN, CONNECTICUT. 

 1899. 



TDTTLE, MOREHOUSE & TAYLOR, PRINTERS, 125 TEMPLE STREET. 



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

 foreign subscribers of countries in the Postal Union. Remittances should 

 be made either by money orders, registered letters, or bank checks. 



