05 
TERTIARV of south AMERICA. 
Stones and other remarkable sedimentary 
deposits; the whole having a very close 
resemblance to some of the tertiary beds on 
the shores of the Pacific. From this 
resemblance I expected to find silicified 
wood which is generally characteristic of 
these formations. I was gratified in a very 
extraordinary manner. In the central part 
of the range^ at an elevation of about seven 
thousand feet^ I observed on a bare slope 
some snow-white projecting columns. 
These were petrified trees eleven being 
silicified, and from thirty to forty converted 
into coarsely crystallized white calcareous 
spar. They were abruptly broken off, the 
upright stumps projecting a few feet above 
the ground. The trunks measured from 
three to five feet each in circumference. 
They stood a little way apart from each 
other, but the whole formed one group. 
Mr. Robert Brown has been kind enough 
to examine the wood: he says it belongs to 
the fir tribe, partaking of the character of 
the araucarian family, but with some cu¬ 
rious points of affinity with the yew. The 
volcanic sandstone in which the trees were 
