1 88 APPENDIX. 
of Salta touched it. The body of this tree extends upon the 
ground in the direction from E. to W. having left behind to 
the E. a part which lies in the direction from N. to S. and it 
is from this that the pieces of metal may have been taken with 
a chiflel. From this account one may venture to form the 
following hypothefis. 
1 will fuppole, that the volcanic explofion happened in the 
fpot where I difcovered the brackifh fpring ; that by the explo- 
fion a great quantity of earth was railed, and formed the eleva- 
tion of this part of the plain above the ref: ; that it was origi- 
nally much higher, but the continual rains of the Chaco, 
which is overflowed a third part of the year, are always a&ing 
to bring it to a level with the reft of the country. 
The direction of the greateft portion of the mafs of iron 
ejected was from E. to W. and being heavier reached to 
the diftance where it is found. Another portion of the 
matter fmaller, and perhaps more fluid, feparated and took 
another direction, running into feveral ftreams, as when water 
is thrown out of a pail. This fmall portion of matter having 
cooled, and the earth which fupported it being wafhed away 
gradually by the water, muft, I apprehend, have formed what 
is now called the Tree of iron. 
The falitie and antimonial matters, which ufually accompany 
all minerals, mud have been fcattered round about in a fimilar 
manner, and rendered the ground barren. 
In the kingdom of Santa Fe de Bogota, there is found fluff 
of platina mixed with gold. Almoft every body knows the 
great affinity there is between thefe two metals, fo that it is 
not furprizing, confidering all thefe reafons, that the fire of the 
volcano fhould have melted the platina which lay above the 
gold, and thrown it up. This principle of volcanos is the 
4 mod 
