EARTHQUAKES IN CENTRAL AMERICA. 819 



the nobler and more refined enjoyments of life, is not improving the 

 instruments for the acquisition of his food ; they deteriorate in his 

 hands — a condition which first began to make its appearance with the 

 invention of cooking. The reduction of the human dentition — which 

 has been of advantage to the species in its sti'uggle for existence — has 

 further increased and changed to a kind of atavism or reversion, since 

 reason, acquired with speech, has made man more and more independ- 

 ent of the direct effects of his natural surroundings. 



Hence it is not merely from a purely zoological point of view that 

 an inference is formed regarding the future change of the human race. 

 Moreover, we cherish the hope — which is justified by scientific experi- 

 ences — and the belief, which rests upon the same foundation, and these 

 convince us of the sure advance of humanity, and of the gi-adual and 

 general diffusion of morality, culture, and well-being among the vari- 

 ous races of man. 



EAKTHQUAKES IN CEKTKAL AMEEICA. 



By M. de MONTESSUS, 

 of the meteoeolooico-seismio obsebvatoby at san 8alvad0e. 



CENTRAL AMERICA is probably the region of the globe in 

 which the manifestations of volcanic and seismic phenomena 

 are most frequent and continuous. During my residence of four 

 years at San Salvador, 1 have been able to write the detailed history 

 of twenty-three hundred and thirty-two earthquakes, one hundred 

 and thirty-seven volcanic eruptions, twenty-seven ruins of important 

 towns, and the formation of three new volcanoes. Geographically, 

 Central America, founded on the Cordillera of the Andes, forms a 

 connecting link between the two great continental masses through 

 three successive isthmuses, those of Panama or Darien, Izabal, and 

 Tehuantepec. It descends to the Atlantic in two large wedges, end- 

 ing in Capes Gracias 4 Dios and Catocha, and rests abruptly on the 

 nearly rectilinear coast of the Pacific. The base of the Cordillera is 

 of primitive formation, and its western flank, with which we are con- 

 cerned, is formed of Miocene and Pliocene strata, terminating with 

 Quaternary and modern alluvions and more or less recent volcanic 

 flows. 



Parallel with this axis runs the remarkable string of volcanoes 

 which, from Chiriqui in the State of Panama, to Soconusco in Mexico, 

 includes not less than one hundred and forty-three volcanic mountains 

 or craters, thirty of which are active, or have been within the three 

 hundred and sixty-three years that separate us from the Spanish Con- 

 quest. They do not present themselves, as is generally believed, upon 

 a straight line or along a volcanic fault, nor even on a line broken at 



