﻿, 
  7^ 
  

  

  THE 
  

  

  AMERICAN 
  

  

  JOURNAL 
  OF 
  SCIENCE. 
  

  

  Editor: 
  EDWARD 
  S. 
  DANA. 
  

  

  ASSOCIATE 
  EDITORS 
  

  

  Professors 
  GEORGE 
  L. 
  GOODALE, 
  JOHN 
  TROWBRIDGE, 
  

   and 
  WM. 
  M. 
  DAVIS, 
  of 
  Cambridge, 
  

  

  Professors 
  A. 
  E. 
  VERRILL, 
  HORACE 
  L. 
  WELLS, 
  CHARLES 
  

  

  SCHUCHERT, 
  H. 
  E. 
  GREGORY, 
  and 
  HORACE 
  S. 
  

  

  UHLER, 
  of 
  New 
  Haven, 
  

  

  Professor 
  JOSEPH 
  S. 
  AMES, 
  of 
  Baltimore, 
  

   Mr. 
  J. 
  S. 
  DILLER, 
  of 
  Washington. 
  

  

  FOURTH 
  SERIES 
  

   VOL. 
  XLIX— 
  [WHOLE 
  NUMBER, 
  CXCIX]. 
  

  

  NEW 
  HAVEN, 
  CONNECTICUT. 
  

  

  19 
  2 
  0. 
  /^ 
  % 
  

  

  Z4rtS(> 
  

  

  

  