ElYEES OF CUBA. 359 



Except on the uplands Cuba mainly consists of calcareous rocks, wliich appear 

 to have been deposited in the same way as the present fringing reefs have been 

 formed, presenting the same irregularities, the same fractures and deep cavities. 

 So numerous are the underground galleries that the whole island may be said to 

 form a vast vault, beneath which the waters are collected either in streams or 

 stagnant reservoirs. Explorers have penetrated for leagues into the labyrinthine 

 passages of many caves without reaching the end, and every year fresh discoveries 

 are made. In many places rivulets are seen to plunge into chasms, reappearing 

 farther on as more copious streams swollen by subterranean affluents. 



In the Vuelta de Abajo a river near Pinar del Rio passes under a superb arch- 

 way like that of the bridge at Arc. Elsewhere the running waters flow in narrow 

 gulches, where the overhanging walls here and there meet overhead. The best- 

 known caverns are those of Monte Libano (" Mount Lebanon ") in the eastern 

 peninsula north of Guantanamo. !Near Cape Maisi, at the eastern extremity of 

 the island, there is also a famous grotto, in which animal remains have been 

 discovered. 



Rivers. 



Although mostly short and with narrow catchment basins, the Cuban streams 

 are generally copious. The Cauto, which is the largest, flows through the longi- 

 tudinal valley along the north slope of the Sierra Maestra, where it collects 

 numerous affluents on both sides. From the Sierra del Cobre to Manzanillo Bay 

 it has a total length of about 130 miles, nearly half of which is navigable for 

 small craft ; vessels of 50 tons ascend as far as the village of Cauto, the '' Embar- 

 cadero," as it is called. In its lower course the mainstream ramifies into two 

 branches, and during the floods into several secondary channels intersecting the 

 low-lying, themselves the creation of the river. 



The alluvia have even encroached on the sea in a long marshy peninsula, 

 which divides the bay into two secondary inlets. In the sixteenth century the 

 bar is said to have been much smaller than at present, and -at that time a brisk 

 trade was carried on in the lower reaches of the river. But in 1616 a great flood 

 shifted the bar and completely closed the mouth of the Cauto. As many as thirty- 

 three vessels were suddenly cut off from access to the sea and had to be ab.mdoned 

 by their crews. Many families, ruined by the cessation of traffic, ultimately 

 removed to Havana. About the middle of the present century the guns of a man- 

 of-war stranded by the disaster were fished up from the muddy bed of the Cauto. 



The other Cuban riv^ers, of which the lirgest are the Sagua la Grande and 

 Sagua la Chica on the north side, are all far inferior in volume to the Cauto. 

 Several, however, are famous for their cascades, their underground course, 

 reappearance on the surface, and their estuaries. Some fail to reach the sea, 

 running out in marshy tracts where the fresh and salt waters are intermingled. 

 These swampy districts attain their greatest develojDment along the south coast, 

 where the extensive Cicnaga de Zapata (-'Marsh of Zapata"), south of the Matanzas 

 uplands, skirts the shore for a distance of 60 miles between the Broa and Cochiuos 



