74 EAMBLES OF A NATUEALIST. [Ch. V. 



showed their occasional activity. Moreover, the edge of the 

 level, where it began to descend down the ravine before men- 

 tioned, was covered with a thick crust, which had evidently 

 been at one time in a semifluid state, and had slowly flowed, 

 a viscous mass, over the edge, and now had the appearance 

 of dried asphalt. This was doubtless the remains of mud, 

 through which the sulphur rose, such as we still saw in some 

 comparatively small pools, but which at one time had been in 

 sufficient quantity to rise above the general depression and 

 run over the edge into the raviae. 



The sulphur appeared ia all cases to be deposited in a 

 perfectly pure sublimed form ; nor was there any smell to 

 be detected in the active springs themselves. The steam is 

 laden with the element in a dissolved condition, and deposits 

 it in pure crystals upon any substance with which it comes 

 in contact. The effects produced upon the exposed rocks 

 were in all cases due to the disintegrating and bleaching 

 effects of steam ; and the smell of sulphuretted hydrogen 

 was most perceptible in a spot where the rocks had been 

 disintegrated, but where there was no sign of present 

 activity. 



It has been supposed that the locality is very fatal to 

 animal life, from the presence of sulphurous vapours, — ^that 

 it is a sort of Avernus, destroying birds and insects which 

 pass in its neighbourhood. But I cannot endorse this view. 

 I myself observed birds and insects flying over it with ease and 

 impunity, nor was any noxious smeU elsewhere perceptible. 

 Any ill effects could be produced only by the direct action of 

 the steam, with which the sidphv/r could have little or nothing 

 to do; and if any corroboration of this were required, it need 

 only be mentioned that the patch occupied by the sulphur- 

 springs is immediately surrounded by the brightest verdure,, 



