﻿has. 
  D. 
  Walcott, 
  

  

  U. 
  S. 
  Geol. 
  Survey. 
  

  

  YOL. 
  XLIX. 
  APKIL, 
  1895. 
  

  

  Established 
  by 
  BENJAMIN 
  SILLIMAN 
  in 
  1818. 
  

  

  THE 
  

  

  AMERICAN 
  

  

  JOURNAL 
  OF 
  SCIENCE. 
  

  

  EDITORS 
  

  

  JAMES 
  D. 
  and 
  EDWARD 
  S. 
  DANA. 
  

  

  ASSOCIATE 
  EDITORS 
  

  

  Professors 
  GEO. 
  L. 
  GOODALE, 
  JOHN 
  TROWBRIDGE, 
  

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

  

  Professors 
  H. 
  A. 
  NEWTON, 
  O. 
  C. 
  MARSH, 
  A. 
  E. 
  VERRILL 
  

   and 
  H. 
  S. 
  WILLIAMS, 
  of 
  New 
  Haven, 
  

  

  Professor 
  GEORGE 
  F. 
  BARKER, 
  of 
  Philadelphia. 
  

  

  THIRD 
  SERIES. 
  

  

  YOL. 
  XLIX— 
  [WHOLE 
  NUMBER, 
  CXLIX.] 
  

  

  No. 
  292.— 
  APRIL, 
  1895. 
  

  

  WITH 
  PLATE 
  III. 
  

  

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

   1895. 
  

  

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

  

  Published 
  monthly. 
  Six 
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  per 
  year 
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