﻿Fig. 
  11. 
  — 
  An 
  enlargement 
  of 
  a 
  portion 
  of 
  the 
  exterior, 
  showing 
  the 
  

   character 
  of 
  the 
  striae. 
  X 
  5. 
  

  

  Staford 
  limestone 
  of 
  the 
  Mareellus 
  shales. 
  Stafford, 
  JSf. 
  Y. 
  

  

  Orthoceras 
  GEdipus, 
  Hall 
  

   Fig. 
  12. 
  — 
  An 
  enlargement 
  of 
  the 
  external 
  surface. 
  X 
  5. 
  

   Hamilton 
  shales, 
  at 
  473 
  feet 
  in 
  the 
  Livonia 
  shaft 
  

  

  3T8 
  

  

  