70 J. W. SPENCER — GEOGRAPHICAL EVOLUTION OF CUBA. 



On the northern side of Cuba the highestlpoint of the interrupted ranges 

 of mountains is Pan de Matanzas, 1,277 feet above tide. It is terraced 

 and sculptured with sea-caves and rifts (see figure 8, page 87). The other 

 inferior and scattered ridges in the central portion of the island trend 

 southwestward, but they are not usually parallel to the coastline. They 

 are the remnants of an earl}^ degradation before the formation of the 

 present plains, which occupy much of the central portion of the island, 

 and which are so level that for long distances no irregularity appears on 

 the horizon. The elevations of the plains between Havana and Matanzas, 

 and for a few miles eastward, seldom exceed 300 or 350 feet, and the ridges 

 which rise out of them may reach altitudes of 300 or 500 feet higher. 

 Farther east, in the vicinitN^ of Colon, the ))lains are not more than from 

 100 to 200 feet high, while in the central part of the island, between Cien- 

 fuegos and Santa Clara, the land again rises to as much as 400 feet above 

 the sea. Although level to the eye, the plains slope toward the shores of 

 both sides of the island. 



The streams in this part of the country are in ver}^ shallow depressions, 

 without the appearance of valley structure, except as they near the coast, 

 where in a distance of five miles they ma}^ descend 300 or 400 feet, and 

 form amphitheater-like valleys two or three miles wide. In man\" locali- 

 ties the drainage is carried off by subterranean outlets. Streams, after 

 flowing at the surface, disappear and again emerge. The Rio Negra north 

 of Trinidad illustrates this feature. 



Between Havana and Matanzas sea-caves may be seen at an altitude of 

 about 350 feet upon the landward side of a higher ridge, thus showing a 

 recent submergence of the plain. 



• Hydrography off thk Coast. 



The submerged coastal shelves have been referred to as continuations 

 of the land features, but across these drowned lands the soundings are 

 infrequent in many localities, yet in others they are abundant enough to 

 show some valleys of great depth. The most notable incision in this en- 

 larged insular mass is the gulf of Cazones,of which Cochinos and Xagua 

 bays are branches (see maj), page 69). Near the head of the gulf the 

 drowned valley is 2,256 feet deep, and increases to over 7,500 feet before 

 reaching the mouth. The length of the incision is 70 miles. The land 

 about the head of the gulf is low, and the valle}^ has there been filled with 

 recent formations. The present low land was a ])lateau into which the now 

 drowned valley extended as far back as the present head of Xagua ba3^ 

 The western side of the fiord is bounded by the submerged portion of the 

 island, where the water between the keys and mangrove islands is, except 



