168 QBOLOOT or CUBA. 



Do they prove a submarine communication between the 

 limestone of the coast with the limestone serving as the 

 basis of lithonhyte polypi, and is the fresh water of Cuba 

 raised up by hydrostatic pressure across the coral rocks of 

 Cayos, as it is in the bay of Xagua, where, in th^ middle 

 of the sea, it forms springs frequented by the lamantins ? 



The secondary formations on the east of the Havannah 

 are pierced in a singular manner by syenitic and euphotide 

 rocks united in groups. The southern bottom of the bay, 

 as well as the northern part (the hills of the Morro and 

 the Cabana), are of Jura limestone ; but on the eastern bank 

 of the two Ensenadas de Regla and Guanabacoa, the whole 

 is transition soil. Going from north to south, and first 

 near Marimelena, we find syenite consisting of a great 

 quantity of hornblende, partly decomposed, a little, quartz, 

 and a reddish-white feldspar seldom crystallized. This fine 

 syenite, the strata of which incline to the north-west, alter- 

 nates twice with serpentine. The layers of intercalated 

 eerpentine are three toises thick. Farther south, towards 

 Eegla and Guanabacoa, the syenite disappears, and the 

 whole soil is covered with serpentine, rising in hills from 

 thirty to iorty toises high, and running from east to west. 

 This rock is much fendillated, externally of a bluish-grey, 

 covered with dendrites of manganese, and internally of 

 leek and asparagus-green, crossed by small veins of as- 

 bestos. It contains no garnet or amphibole, but metalloid 

 diallage disseminated in the mass. The serpentine is some- 

 times of an esquillous, sometimes of a conch oidal fracture : 

 this was the first time I had found metalloid diallage within 

 the tropics. Several blocks of serpentine have magnetic 

 poles ; others are of such a homogeneous texture, and have 

 such a glossiness, that at a distance they may be taken for 

 pechstein (resinite). It were to be wished that these fine 

 masses were employed in the arts, as they are in several 

 parts of Germany. In approaching Guanabacoa, we find 

 serpentine crossed by veins between twelve and fourteen 

 inches thick, and filled with fibrous quartz, amethyst, and 

 fine mammelonnes, and stalactiforme chalcedonies ; it is pos- 

 sible that chrysoprase may also one day be found. Some 

 copper pyrites appear among these veins, accompanied, it 

 is said, by silvery-grey copper. I found no traces of ttua 



