POPOCATEPETL AND IXTACCIHUATL—FARRINGTON. 89 
of dry grass were dotted here and there with stunted pines, in the 
branches of which robins and blue birds chirped and twittered. 
Another stretch of pine woods was then encountered in a region 
deeply intersected with ravines. The trees here were of considerable 
size and thickly distributed. To the left of the trail rose the rugged 
peak of Cerro Tlamacas, belonging to the ridge which extends north- 
east from Pico del Fraile. This ridge seems to have had an indepen- 
dent origin from the main cone, as is indicated both by its topography 
and the character of its rock masses. Its rocks are a vitreous ande- 
site and trachytes, none of which contain augite.* Areas of sand 
thrown out at some time from the volcano were common hereabouts, 
as were also tumuli of pumice, the latter a light, felt-like scoria con- 
taining tabular crystals of feldspar and augite disseminated through 
its mass. 
a, Ska aan eR aE 

Copyright by Schlattman Brothers. 
; FiG. 1. THE RANCH OF TLAMACAS. 
About 5 Pp. M. we arrived at the Ranch of Tlamacas. This is 
simply a collection of rude shanties used for housing the men who 
mine sulphur in the crater and for carrying on the refining of sulphur. 
The sulphur is at present mined for only about two months of the 
year, June and July. These months are chosen because at this sea- 
* Aguilera and Ordofiez, of. cit. p. 47. 
