306 Notice of Active and Extinct Volcanos. 



"In the month of June, 1759, a subterraneous noise was heard. 

 Hollow sounds of the most alarming nature were accompanied by 

 frequent earthquakes, which succeeded each other for from fifty to 

 sixty days, to the great consternation of the inhabitants of the 

 farm. From the beginning of September every thing seemed to 

 announce the complete re-establishment of tranquillity, when in 

 the night of the 28th and 29th, the horrible subterraneous noise 

 recommenced. The affrighted Indians fled to the mountains of 

 Aguasarco. A tract of ground from three to four square miles in 

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

 vulsion are still distinguishable from the fractured strata. 



" The Malpays near its edges is only thirty-nine feet above the 

 old level of the plain, called Las Playas de Jorullo ; but the con- 

 vexity of the ground thus thrown up increases progressively to- 

 wards the centre to an elevation of five hundred and twenty -four 

 feet. 



" Those who witnessed this great catastrophe from the top of 

 Aguasarco assert, that flames were seen to issue forth for an ex- 

 tent of more than half a square league, that fragments of burn- 

 ing rocks were thrown to prodigious heights, and that through a 

 thick cloud, of ashes, illumined by volcanic fire, the softened 

 surface of the earth was seen to swell up like an agitated sea. 

 The rivers of Cuitimba and San Pedro precipitated themselves 

 into the burning chasms. The decomposition of the water con- 

 tributed to invigorate the flames, which were distinguishable at 

 the city of Pascuaro, though situated on a very extensive table 

 land, four thousand five hundred and ninety-two feet above the 

 plains of Las Playas de Jorullo. Eruptions of mud, and espe- 

 cially of strata of clay, enveloping balls of decomposed basalt in 

 concentrical layers, appear to indicate that subterraneous water 

 had no small share in producing this extraordinary revolution. 

 Thousands of small cones, from six to ten feet in height, called 

 by the natives ovens (hornitos) issued forth from the Malpays. 

 Although, according to the testimony .of the Indians, the heat of 

 these volcanic ovens has suffered a great diminution during the 

 last fifteen years, I have seen the thermometer rise to two hun- 

 dred and twelve degrees on being plunged into fissures which 

 exhale an aqueous vapour. Each small cone is a fumarole, from 

 which a thick vapour ascends to the height of from twenty-two 

 to thirty-two feet. In many of them a subterraneous noise is 

 heard, which appears to announce the proximity of a fluid in 

 ebullition. 



" In the midst of the ovens, six large masses, elevated, from 

 three hundred to one thousand six hundred feet each, above the 

 old level of the plains, sprung up from a chasm, of which the di- 



