go FreELD CoLuMBIAN MusEuM—GEoLoey, VOL. I. 
son the quantity of snow on the cone is sufficient to allow of making 
a smooth trough on which the sulphur can be slid from the crater to 
the ranch. All of the sulphur which has gathered in the crater during 
the year, so far as it is accessible, is taken out at this time. The 
sulphur is refined simply by heating in large earthen retorts. From 
these it passes over intoother earthen jars and condenses. The proc- 
ess is crude and simple, but the product obtained is quite pure and 
free from the sand and other impurities which were intermingled with 
it in the original deposit. 
The following table shows altitudes in this region as they have 
been determined by different observers: 
ALTITUDES. OF POINTS NEAR ‘THE RANCH. OF TLAMAGCAS: 



METERS.) sPEET. 

Ranen of Plamacasie.s ae ae 3,897 12,786 | Dollfus, 1865. 
3,899.4 12,794 | Sonntag, 1857. 
3,931 12,897 | Aguilera and Ordofiez, 

1894. 
erro Waniacas chars tan cre erate 4,072 13,359 | Sonntag. 
| ta OS coy Agee eae ee ee Ag ones A Rao e RA 4,300 14,108 | Felix and Lenk, 1887. 


On dismounting from my horse at the ranch I noticed for the first 
time symptoms of mountain sickness due to the altitude. I found 
myself exceedingly dizzy, my heart beat violently and I was obliged 
to pant in order tq supply my system with sufficient air. I had also 
considerable nausea, throbbing of the temples, and other indications 
that my system revolted at being raised to so great an altitude. The 
acuteness of the symptoms wore off in an hour or two, but the excess 
of blood at my head continued in sufficient force to prevent much 
sleep that night, and the nausea persisted with greater or less severity 
throughout the following day. Not all travelers experience these 
symptoms to the same degree, but the strain on the heart and lungs 
especially is so severe that no one not possessed of sound organs 
should essay the height. 
After a cold and sleepless night at the ranch we mounted our 
horses about 6 a. Mm. for the ascent of the cone. The first part of the 
way lay through a growth of pines which gradually became more 
stunted and scraggly till they disappeared entirely at an altitude 
determined by Aguilera and Ordofiez as 13,222 feet. 
The Barranca of Tlamacas was then crossed, giving an oppor- 
tunity to see a section of some of the overlying strata. The barranca 
is produced by the downflow of the waters gathered in the semi-circu- 
