TEINIDAD. 59 



coast ranges vary in mean altitude from l,oOO to 3,000 feet. The two culminating 

 points, Tucutche (Las Cuevas), in the middle of the cordillera, and the Cerro de 

 Aripo in the north-eaat, attain the respective heights of 3,100 and 2,644 feet. The 

 rugged crags of the Dragon's Mouth are over 650 feet high, one of them in Mono 

 (" Monkey ") Island rising to 1,000 feet. But even on the steepest slopes strewn 

 with ruptured blocks, the bare rock is everywhere concealed by a leafy vegetation. 



South of the chain of primitive rocks skirting the north side of Trinidad the 

 plains and undulating tracts constituting most of the surface belong to the same 

 cretaceous horizon as those facing the coast range along the Gulf of Cariaco, as 

 well as those reappearing west of the Unare to the south of the Caracas coast 

 range. The uniformity of the inland plains is broken only by Mount Tamana, 

 a solitary mass 1,028 feet high, and mariners plying on the Gulf of Paria guide 

 their course by the crest of Mount Naparima, which rises 590 feet above the water 

 near the town of San Fernando. 



Lastly, the south side of Trinidad, which, like the north, affects the aspect of a 

 coast range, consists of dunes and tertiary rocks, as- does also the chain of heights 

 which, beyond the muddy banks deposited by the Orinoco and neighbouring streams, 

 forms the northern edge of the llanos. 



The south-western, like the north-western, peninsula terminating the Trinidad 

 quadrilateral is continued towards the mainland by an islet, some reefs and the 

 Soldado rock, which at a distance resembles a sail, and which is enveloped in a 

 cloud of countless sea-fowl. Thus in all the elements constituting its framework 

 Trinidad is essentially a part of the mainland. Even the shores of recent forma- 

 tion, by which its surface is increasing, are of continental origin. The sands and 

 muds, which develop a convex curve on the east side washed by the Atlantic, have 

 been brought down by the currents of the Amazons, of the Guiana rivers and the 

 Orinoco. The channels of the Serpent's Mouth, giving access to the Gulf of Paria 

 along the south side of the island, are no longer deep troughs like the northern 

 channels of the Dragon's Mouth. They have already been partly filled in by the 

 alluvial matter washed down with the Orinoco current. The yearly soundings 

 show constantly varying results. Thus the east passage has shoaled from 8 to 

 4 fathoms, while in that of the west beyond the Soldado reefs the Une every- 

 where reveals 12 or 13 fathoms ; here the marine bed is incessantly scoured by a 

 regular current. 



Geological Changes. 



Trinidad givres undoubted evidence of having undergone great geological 

 revolutions. Erosions have taken place to a vast extent, as shown by the masses of 

 quartz, containing some magnificent rock crystals, which are met on the plains, in 

 the valleys, and on the hillsides. These are evidently the remains of old crystal- 

 line rocks, all the softer parts of which have disappeared, either changed to alluvia 

 or carried away to the sea. Great beds of gravel or shingle 300 or 400 feet thick 

 are seen at the southern entrance of all the valleys along the northern coast range. 

 In a more northern zone, such, for instance, as Scandinavia, moraines would 



