Chap. VIII. SIERRA DE LOS ORGANOS. 319 
forms the prevailing vegetation. Other tracts are covered 
with various kinds of shrubs, especially of the wormwood 
family (Artemisia), and a grey-leaved Chenopodiacea. 
Scattered between these shrubs grow tree-like Yuccas. 
As the traveller proceeds south their stems grow taller ; 
the plant assumes the appearance of a small palm-tree, 
and accordingly is called " Palmilla " by the Mexi- 
cans. The disproportionate thickness of the stem is pro- 
duced by the withered leaves clinging around it. Toward 
evening we reached a small group of low trachytic hills. 
The trachyte is bordered by limestone, which in appear- 
ance resembles that on the Ojo de Verendo. The trachyte 
exhibits some degree of stratification, and in some parts 
encloses fragments of hornblende, flint, with other kinds of 
rock, and thus forms a breccia. This spot is known to the 
American traders as the " Point of Rocks." The Mexi- 
cans call it " Peril! a." 
The mountains bounding the terrace of the Jornada to 
the west, consist of isolated groups. Those to the east, 
form a long unbroken chain divided in sections, becoming 
towards the south more lofty, precipitous, and indented. 
The next morning a snowy peak of the Sierra Blanca 
(White Mountains) was visible behind a depression of the 
nearer chain. On the south side of the terrace, where the 
road descends towards the Rio Grande, a circular group 
of dark rocky hills stands forth like an island in the plain, 
apparently the remains of an old volcano. Behind these, 
to the left, rose the sharp peaks of the Sierra de los 
Organos, the southern extremity of the above-named chain. 
The setting sun shed a marvellous beauty upon these 
mountains, the small group standing out in a dusky brown, 
with black shadows, while the prominent peaks of the 
more distant Sierra de los Organos were bathed in tender 
