ANNOTATIONS AND ADDITIONS. 187 



: ANNOTATIONS AND ADDITIONS. 



(*) p. 170. "Across tJie peaceful ocean arm, which fills the wide 

 valley between the American shore and Western Africa." 



The Atlantic Ocean, from the 23d degree of south, -to the 70th 

 degree of north latitude, has the form of an excavated longitudinal 

 valley, in which the salient and re-entering angles are opposite to 

 each other. I first developed this idea in my " Essai d'un Tableau 

 geologique de TAmerique meridionale/'. printed in the Journal de 

 Physique, t. liii. p. 61. (Geognostische Skizze von Siidamerika, in 

 Gilbert's Annalen der Physik, bd. xvi. 1804, s. 394-449.) From 

 the Canaries, and especially from the 21st degree of north latitude 

 and the 23d degree of west longitude, to the north-east coast of 

 South America, the surface of the sea is usually so calm, and the 

 waves so gentle, that an open boat might navigate in safety. 



*^P? . '.^-"'-^'r, 



( 2 ) p. 170. "A wonderful outbreak of fresh springs m the midafa qf 



the ocean." 



On the southern coast of the Island of Cuba, south-west of the 

 Port of Batabano, in the Gulf of Xagua, a few miles from the coast, 

 springs. of fresh water gush from the bed of the ocean, probably un- 

 der the influence of hydrostatic pressure, and rise through the midst 

 of the salt water. They issue forth with such force that boats are 

 cautious in approaching this locality, which has an ill repute on ac- 

 count of the high cross sea thus caused. Trading vessels sailing 

 along the coast, and not disposed to land, sometimes visit these 

 springs to take in a supply of fresh water, which is thus obtained in 

 the open sea. The greater the depth from which the water is taken, 

 the fresher it is found to be. The "river cow/ 7 Trichecus manati, 

 which does not remain habitually in salt water, is often killed here. 

 This remarkable phenomenon of fresh springs issuing from the sea, 

 has been most carefully examined by a friend of mine, Don Fran- 



