OF THE EAllTH S SURFACE. 165 



tendant waves, have exerted their influence, and which liave 

 probably left behind them very striking monuments of their 

 power. I conceive that in this way, the doctrines already ad- 

 vanced in this paper, and which I am now about more fully 

 to illustrate, will be submitted to the test of direct observa- 

 tion. 



The fact which I have met with most strictly in point, oc- 

 -curs in Humboldt's Account of Mexico, Eng. Trans. London, 

 1811, vol. ii. p. 212. At San Pedro de Jerullo, " in the month 

 " of June 1759, a subterraneous noise w^as heard. Hollow 

 ^' noises of a most alarming nature {hramidos) were accompa- 

 *' nied by frequent earthquakes, which succeeded one another 

 " from fifty to sixty days, to the great consternation of the in- 

 ^' habitants of the Hacienda. From the beginning of Septem- 

 " ber, every thing seemed to announce the complete re-esta- 

 " blishment of tranquillity, when, in the night between the 

 " 28th and 29th, the horrible subterraneous noise recommen- 

 " ced. The affrighted inhabitants fled to the mountains of 

 " Aquasarco. A tract of groimd, from three to four square 

 *'■ miles in extent, which goes by the name of the Malpays, 

 " rose up in the shape of a bladder. The bounds of this con- 

 " vulsion are still distinguishable in the fractured strata. The 

 " Malpays near its edges is only twelve metres (thirty-nine 

 " feet) above the old level of the plain, called Playas de Jo- 

 " ruUo ; but the convexity of the ground thus thrown up, in- 

 ** creases progressively towards the centre, to an elevation of 

 " one hundred and sixty metres (five hundred and twenty-four 

 " feet)." 



In this most striking and interesting scene, we have an ac- 

 tual specimen of those violent and sudden operations by which 

 our continents have been raised to their present position, ac- 

 cording 



