328 COSMOS. 



If the terrible, black lava-field Malpais (upon which I 

 have here purposely dwelt in order to counteract the too 

 one-sided consideration of exertions of volcanic force from 

 the interior), did not flow from the Cofre de Perote itself at a 

 lateral opening, still the upheaval of this isolated mountain 

 13,553 feet in height, may have caused the formation of the 

 Loma de Tablas. During such an upheaval, longitudinal 

 fissures and networks of fissures may be produced far and 

 wide by folding of the soil, and from these, molten masses 

 may have poured directly, sometimes as dense masses, and 

 sometimes as scoriaceous lava, without any formation of true 

 mountain platforms (open cones or craters of elevation). 

 Do we not seek in vain in the great mountains of basalt and 

 porphyritic-slate, for central points (crater-mountains) or lower, 

 circumvallated, circular chasms, to which their common pro- 

 duction might be ascribed ? The careful separation of that 

 which is genetically different in phenomena : the forma- 

 tion of conical mountains with permanently open craters 

 and lateral openings ; of circumvallated craters of elevation 

 and Maars ; of upraised closed bell-shaped mountains or open 

 cones, or matters poured out from coalescent fissures 

 is a gain to science. It is so because the multiplicity of 

 opinions which is necessarily called forth by an enlarged 

 ho-izon of observation, and the strict critical comparison of 

 that which exists, with that which is asserted to be the 

 only mode of production, are most powerful inducements 

 to investigation. Even upon European soil, however, on the 

 island of Eubcea, so rich in hot springs, a vast lava-stream 

 has been poured out, 80 within the historical period, from 

 a chasm in the great plain of Lelanton, at a distance from 

 any mountain. 



In the volcanic group of Central America, which follows 

 the Mexican group towards the south, and in which eighteen 

 conical and bell-shaped mountains may be regarded as still 

 active, four (Nindiri, el Nuevo, Conseguina, and San Miguel 

 de Bosotlan) have been recognized as producing lava. 81 The 

 mountains of the third volcanic group, that of Popayan and 

 Quito, have already for more than a century enjoyed the re- 



20 Strabo, lib. i, p. 58, lib. vi, ,. 269, ed. Casaubon; Cosmos, vol. i, 

 p. 236, and vol. v, p. 225. 

 31 See page 278. 



