PREFACE 



TO THE SECOND EDITION. 



The principal additions wliich have been made to this work 

 in the preparation of the second edition are : an abstract of 

 an important paper on the Bahamas, by Captain (now Major- 

 General) Nelson, R.E., read before the Geological Society of 

 London in 1852 ; an account of the interesting observations of 

 Mr. J. Matthew Jones, from Nature of August 1872, bearing 

 on the former extent of the Bermudas; facts stated by 

 Mr. S. J. Whitnell with regard to some Pacitic coral islands ; 

 and a report of the planting, by MM. Le Clerc and De 

 Benaze, of slabs of coral rock at Tahiti, near the slab placed 

 by Admiral Wilkes, to aid in future determinations of the rate 

 of growth of the Dolphin Shoal, together with a Map of the 

 region. Other minor changes have been made which it is 

 not important here to enumerate. 



James D. Dana. 



March, 1875, 



