20 St J ago. paet l 



found an irregular circular group of masses of cemented, 

 scoriaceous breccia, about six feet in height, which 

 doubtless had once formed the point of eruption. The 

 third orifice is now marked only by an irregular circle 

 of cemented scoriae, about four yards in diameter, and 

 rising in its highest point scarcely three feet above the 

 level of the plain, the surface of which, close all round, 

 exhibits its usual appearance : here we have a hori- 

 zontal basal section of a volcanic spiracle, which, to- 

 gether with all its ejected matter, has been almost 

 totally obliterated. 



The stream of lava, which fills the narrow gorge l 

 eastward of the town of Praya, judging from its course, 

 seems, as before remarked, to have come from Signal 

 Post Hill, and to have flowed over the plain, after its 

 elevation : the same observation applies to a stream 

 (possibly part of the same one) capping the sea cliffs, a 

 little eastward of the gorge. When I endeavoured to 

 follow these streams over the stony level plain, which-is 

 almost destitute of soil and vegetation, I was much 

 surprised to find, that although composed of hard 

 basaltic matter, and not having been exposed to marine 

 denudation, all distinct traces of them soon become 

 utterly lost. But I have since observed at the Gala- 

 pagos Archipelago, that it is often impossible to follow 

 even great deluges of quite, recent lava across older 

 streams, except by the size of the bushes growing on 

 them, or by the comparative states of glossiness of their 

 surfaces, — characters which a short lapse of time would 

 be sufficient quite to obscure. I may remark, that in a 

 country, with a dry climate, and with the wind blowing 



1 The sides of this gorge, where the upper basaltic stratum is 

 intersected, are almost perpendicular. The lava, which has since 

 filled it up, is attached to these sides, almost as firmly as a dike is to 

 its walls* In most cases, where a stream of lava has flowed down a 

 valley, it is bounded on each side by loose scoriaceous masses. 



