﻿Report 
  U. 
  S. 
  F. 
  C. 
  1897. 
  (To 
  face 
  page 
  340.) 
  

  

  Plate 
  V. 
  

  

  FIG 
  1, 
  INNER 
  FACE, 
  AND 
  FIG. 
  2, 
  OUTER 
  FACE 
  OF 
  SHELL 
  OF 
  TYPICAL 
  AMERICAN 
  OYSTER. 
  

   From 
  Fourth 
  Annual 
  Report, 
  U. 
  S. 
  Geological 
  Survey. 
  

  

  