290 THE OVEXS OF JORULLO. 



top of Aguasarco, asserted that flames were seen to issue 

 forth for an extent of more than half a square league, 

 that fragments of burning rocks were thrown up to pro- 

 digious heights, and that through a thick cloud of ashes, 

 illumined by the volcanic fire, the softened surface of 

 the earth was seen to swell like an agitated sea. The 

 rivers of Cuitamba and San Pedro precipitated them- 

 selves into the burning chasms. The decomposition of 

 the water contributed to invigorate the flames, which 

 were distinguishable at Pascuaro, though it was situated 

 on extensive table-land, four thousand six hundred 

 feet elevated above the plains of Jorullo. Eruptions of 

 mud, and especially of strata of clay enveloping balls of 

 decomposed basalts in concentrical layers, appeared to 

 indicate that subterraneous water had no small share in 

 producing this extraordinary revolution. Thousands of 

 small cones, from six to nine feet in height, called by the 

 Indians ovens, issued forth from the Malpays. Each 

 small cone was a funnel, from which a thick vapour 

 ascended to the height of forty or fifty feet. In many 

 of them a subterraneous noise was heard, which appeared 

 to announce the proximity of a fluid in ebullition. 



In the midst of the ovens six large masses elevated 

 from thirteen hundred to seventeen hundred feet each 

 above the old level of the plains, sprung up from a 

 chasm. The most elevated of these enormous masses 

 was the great Volcano of Jorullo. It was continually 

 burning, and had thrown up from the north side an im- 

 mense quantity of scorified and basaltic lavas containing 

 fragments of primitive rocks. These great eruptions of 

 the central volcano continued till the month of February, 

 1760. In the following years they became gradually les 



^.-5 



