PHYSICAL FEATUEES OF PANAMA. 813 



to tliis section of tlie cordillera. Farther on it takes the name of the Yeragua 

 range, which begins on the west side with the superb Mount Santiago (6,300 

 feet), followed by several others over 4,000 feet high. 



In this region, the whole of the isthmus, from ocean to ocean, is filled with 

 mountains or hills, with spurs projecting northwards to the Atlantic coast, and 

 penetrating southwards through the massive peninsula of Las Palmas, west of 

 Montijo Bay, far into the Pacific. But the quadrangular j)eninsula of Azuero, 

 which limits the Gulf of Panama on the south-west, is physically distinct from 

 the Yeragua range, from which it is separated by depressions and grassy rising 

 grounds about 500 feet high, culminating south-westwards in a headland exceeding 

 3,000 feet. The Azuero peninsula, in fact, forms part of an almost completely 

 submerged chain, which is disposed parallel with the winding isthmian Cordilleras, 

 and which embraces the Mcoya peninsula, with those of the Golfo Dulce and 

 Burica, besides Coiba Island and the Pearl Archipelago in Panama Bay. 



North-west of the Yeragua range the orographic system becomes very 

 irregular in direction and altitude, being broken into several fragments, whose 

 original trend it is now difiicult to determine. Capira, the culminating mass 

 (5,000 feet), lies beyond the line of the main axis, its escarpments plunging 

 southwards into Panama Bay, and even projecting seawards in the little Cerro 

 Chame. The main axis itself appears to be continued in the Ahoga-Yeguas 

 hills, which are crossed by a pass only 380 feet high, and which nowhere exceed 

 700 feet. Farther on is opened the still lower Culebra Pass (290 feet), which is 

 distant about 34 miles in a straight line from both oceans. 



The geological constitution of the isthmian heights shows that their various 

 sections belong to no single homogeneous system. The Yeragua range consists 

 mainly of granites and syenites, gneiss and schists, whereas the Panama hills are 

 chiefly weathered dolerites and trachites, " which may be cut with a spade like 

 cheese." But these igneous heights nowhere present the aspect of erupted cones. 

 Hence t"he eruptions must have taken place at a time when the waters of the two 

 oceans communicated throu<?h channels. The limestone banks occurring' in cer- 

 tain parts of the isthmus are also filled with fossils, dating, probably, from early 

 tertiary times, and mostly resembling the forms still living in the neighbouring 

 waters. The channel, in fact, is scarcely completely closed, though the attempts 

 of engineers to reopen it have hitherto failed. The depression, however, is traversed 

 by an interoceanic road and railway. 



Beyond the Culebra sill the mountains again graduallj^ rise eastwards, the Maria 

 Enriquez (1,340 feet) being followed by those of Pacora, which are nearly 1,700 

 feet high. Then in the neighbourhood of San Bias Bay is developed a coast- 

 range disposed Avest and east along the Atlantic, and in one of its crests just east 

 of Puerto Belo attaining an elevation of over 3,000 feet. The system is continued by 

 a steep ridge from 500 to 2,700 feet, which here forms the waterparting between 

 the two oceans at the very narrowest part of the isthmus. The distance between 

 San Bias Bay and the head of the Pacific tidal wave in the Rio Bayano scarcely 

 exceeds 17 miles. But the crest where the Bayano has its source is over 1,000 



