256 coSxMos. 



Pacific Ocean. "Where the line of the Central American vol- 

 canoes enters with the volcano of Conchagua into the state 

 of San Salvador, in the latitude of 13^° (to the north of the 

 Bay of Fonseca), the direction of the volcanoes changes at 

 once with that of the west coast. The series of the former 

 then strikes E.S.E. — -W.N.W. ; indeed, where the burning 

 mountains are again so closely approximated that five, still 

 more or less active, are counted in the short distance of 120 

 miles, the direction is nearly E. — W. This deviation cor- 

 responds with a great dilatation of the continent toward the 

 east in the peninsula of Honduras, where the coast tends also 

 suddenly, exactly east and west, from Cape Gracias a Dios 

 to the Gulf of Amatique for 300 miles, after it had been pre- 

 viously rurfhing from north to south for the same distance. 

 In the group of elevated volcanoes of Guatemala (lat. 14° 10^) 

 the series again acquires its old direction, N. 45° W., which 

 it continues as far as the Mexican boundary toward Chiapa 

 and the isthmus of Pluasacualco. Northwest of the volcano 

 of Soconusco to that of Tuxtla, not even an extinct trachytic 

 cone has been discovered ; in this quarter granite abounding 

 in quartz and mica-schist predominate. 



The volcanoes of Central America do not crown the ad- 

 jacent mountain chains, but l-ise along the foot of the latter, 

 usually completely separated from each other. The greatest 

 elevations lie at the two extremities of the series. Toward 

 the south, in Costa Eica, both seas are visible from the sum- 

 mit of the Irasu (the volcano of Cartago), to which, besides 

 its elevation (11,081 feet), its central position contributes. 

 To the southeast of Cartago there stand mountains of ten or 

 eleven thousand feet : the Chiriqui (11,262 feet) and the Pico 

 Blanco (11,740 feet). We know nothing of the nature of 

 their rock, but they are probably unopened trachytic cones. 

 Farther toward the southeast, the elevations diminish in Ver- 

 agua to six and five thousand feet. This appears also to be 

 the average height of the volcanoes of Nicaragua and San Sal- 

 vador; but toward the northwestern extremity of the whole 

 series, not far from the new city of Guatemala, two volcanoes 

 again rise above 13,000 feet. The maxima consequently fall 

 into the third group of my attempted hypsometric classifica- 

 tion of volcanoes, coinciding with ^tna and the Peak of Ten- 

 erifife, while the greater number of the heights lying between 

 the two extremities scarcely exceed Vesuvius by 2000 feet. 

 The volcanoes of Mexico, New Granada, and Quito belong to 

 the fifth group, and usually attain an elevation of more #han 

 17,000 feet. 



