296 MEXICO, CENTEAL AMERICA, WEST INDIES. 



Physical Features. 



Taken as a whole Costa Rica may be regarded as an elevated tableland domi- 

 nating the flooded Nicaraguan depression. Immediately to the south of this vast 

 basin, the hills rise from tier to tier to the crest of the igneous cordillera which 

 is disposed north-west and south-east. "Within some 20 miles to the south of 

 the narrow zone between Salinas Bay and Lake Nicaragua, the Orosi volcano, 

 which still emits a few jets of vapour from its verdure-clad crater, rises to a 

 height of 8,700 feet. 



Beyond it follows the almost isolated four-crested liincon de la Vieja, and 

 still in the same south-easterly direction the Miravalles peak (4,720 feet), 

 crowned with an extinct forest-clad crater. Miravalles and its neighbour, 

 Tenorio, are continued south-eastwards by the Cerros de los Guatusos, which for 

 about 60 miles are destitute of a single igneous cone. But towards the centre 

 of the isthmus the Poas volcano rises to a height of 8,700 feet, and terminates 

 in three craters, one flooded with a lake which drains through the Hio Angel to 

 the Sarapiqui, and another filled with hot water from which vapours are still 

 occasionally emitted to a great height. In 1834 it was the scene of a violent 

 eruption ; but Barba, its eastern neighbour, has long been quiescent, its terminal 

 crater (9,000 feet) being also flooded, like so many others in this region. 



Farther on stands Irazu, giant of the Costa Rican volcanoes, which rises to 

 the north of Cartago, and from whose summit a wide prospect is commanded of 

 both oceans, and of the whole of Costa Rica from the Orosi peak to Mount Rovalo. 

 Yet it slopes so gently that the traveller may reach its culminating point, a little 

 over 11,200 feet, mounted on a mule. The lower flanks are covered with maize, 

 tobacco, and other plantations, diversified with pasturage and terminating with 

 oak forests. The hamlet of Birris, highest inhabited spot in the republic, stands 

 at an altitude of 9,400 feet. 



Turialba (11,000 feet), last cone going eastwards, has greatly contributed by 

 its explosions to modify the general relief of the land. Since the eruption of 

 1866 it has never ceased to eject copious vapours, accompanied now and then with 

 some ashes. Its name is said to be a corrupt form of the Latin turn's alba, 

 " White Tower," though Thiel and Pittier have shown that the word is of Indian 

 origin. 



Tlie Costa Rican igneous chain does not run jDarallel w^ith the Pacific, but 

 trends in a slightly oblique direction to the general axis of this part of the penin- 

 sula, even develoj)ing a gentle curve with its convex side facing southwards 

 and its more lofty section disposed transversely towards the Atlantic. It appears 

 from Pittier's observations that the older cones began their eruptions early in 

 secondary times, when the range stood in the midst of the sea, running in the 

 same way as the insular volcanoes of the Hawaii archipelago. The former 

 existence of such an archipelago is shown by the sedimentary matter now filling 

 the intervals between the igneous crests. 



According to the same authority some of the Costa Rican cones have ejected 



