l92 CAYO DE PIEDRAS. 



herbivorous animals,* find them in abundance in the open 

 sea. 



Half a mile east of Cayo Flamenco, we passed close to 

 two rocks, on which the waves break furiously. They are 

 the Piedraa de Diego Perez (latitude 21 58' 10*'.) The 

 temperature of the sea, at its surface, lowers at this point 

 to 22*6 cent., the depth of the water being only about 

 one fathom. In the evening we went on shore at Cayo de 

 Piedras; two rocks connected together by breakers, and 

 lying in the direction of N.N.W. to S.S.E. On these rocks 

 which form the eastern extremity of the Jardinillos many 

 vessels are lost, and they are almost destitute of shrubs, 

 because shipwrecked crews cut them to make fire-signals. 

 The Cayo de Piedras is extremely precipitous on the side 

 near the sea ; and towards the middle there is a small 

 basin of fresh water. We found a block of madrepore in 

 the rock, measuring upwards of three cubic feet. Doubtless 

 this limestone formation, which at a distance resembles Jura 

 limestone, is a fragmentary rock. It would be well if this 

 chain of cayos which surrounds the island of Cuba, were 

 examined by geologists with the view of determining what 

 may be attributed to the animals which still work at the 

 bottom of the sea, and what belongs to the real tertiary 

 formations, the age of which may be traced back to the 

 date of the coarse limestone abounding in remains of litho- 

 phite coral. In general, that which rises above the waters 

 is only breccia, or aggregate of madreporic fragments 

 cemented by carbonate of lime, broken shells, and sand. 

 It is important to examine, in each of the cayos, on what 

 this breccia reposes ; whether it covers edfices of mollusca 

 still living, or those secondary and tertiary rocks, which 

 judging from the remains of coral they contain, seem to be 

 the product of our days. The gypsum of the cayos oppo- 



* Possibly they subsist upon sea- weed in the ocean, as we saw them 

 feed, on the banks of the Apure and the Orinoco, on several species of 

 Panicum and Oplismenus (camalote ?). It appears commcjh enough, *pn 

 the coast of Tabasco and Honduras, at the mouths of rivers, to find the 

 manatis swimming in the sea, as crocodiles do sometimes. Dampier Dis- 

 tinguishes between the fresh-water and the salt-water manati. (Voyagei 

 and Descr., vol. ii.) Among the Cayos de las doce leguas, east of Xagua, 

 orne islaud* bear the name of MeganoM del Manati. 



