382 



humboldt's cuba. 



waves dash loudly. They were the Piedras de Diego 

 Perez. The temperature of the sea, at the surface, 

 fell there to 22°.6 0. (T2°.7 F.), the depth of water 

 being only six and a half feet. In the afternoon, we 

 reached Cay de Piedras, which is formed by two 

 rocks with breakers between, running NJST.E. and 

 W.S.W. As these two rocks are some distance 

 apart (forming the eastern side of the Jardinillos), 

 many vessels are lost upon, them. The cay has 

 hardly any trees upon it, for those who are ship- 

 wrecked there, have cut them down in their need 

 to make signal fires. The shore is very steep toward 

 the sea, but near the middle there is a small channel 

 with still water. 



We found inclosed in the rock a lump of madre- 

 pore, more than three cubic feet in size; and we 

 entertained no doubt that the limestone formation, 

 which from a distance appears much like the Juras- 

 sic limestone, was a fragmentary rock. It is desira- 

 ble that geognostic travellers should some day 

 examine the entire chain of cays that surround the 

 island of Cuba, in order to determine what is due to 

 the insects that still labor in the depths of the sea, 

 and what belongs to the true tertiary formations, 

 whose epoch approaches very nearly with that of the 

 coarse limestone which abounds among the remains 

 of the coral lithophites. That which generally rises 



