476 A MURDERER JOINS OUR PARTY. Book III. 
Composites, with green, pointed, leafless stalks, and small 
white flowers ; it grows luxuriantly over many square 
miles, but quite unfit for fodder. 
To the west, this green bottom-land is bordered by a 
lateral terrace with a steep declivity, which, forming a 
kind of plateau, has given its name to the place. Mesilla 
is the diminutive of Mesa, or table — a word by which the 
Mexicans designate a plateau. On the 12th we began to 
ascend to this terrace : the road presenting interesting geo- 
logical features, disclosed in a rocky fissure near the road. 
Masses of porphyry lie here, over nearly horizontal 
strata of limestone, containing fossil shells, and which 
have been much changed by the influence of heat iri 
contact with the plutonic or volcanic rock. Higher up 
the road led us through the deep ravines of an exten- 
sive and interesting formation of gypsum, where the 
inhabitants of New Mexico fetch isinglass for window- 
panes. 
Viewed from this height, the valley of Mesilla, with its 
green bottom, the river seen here and there through a 
thick grove of poplars, and the opposite range of the 
Sierra de los Organos, presents an aspect of truly imposing 
grandeur. 
We passed the night on this elevation, and our animals 
were driven back into the valley for grass and water. 
Whilst encamped here, a North American — Mr. W., 
from Virginia — joined us. He had been living in New 
Mexico, where he had committed a murder, and, to escape 
the consequences of this deed, he begged permission to 
travel with us to California. Such company cannot be 
avoided in these countries. I have observed this man for 
months during the journey, and found him to be very good- 
natured and to have many good qualities ; but he could 
