520 ARRIVAL AT COLORADO. Book III. 
before the advent of the summer rains. At the same 
place I saw, for the first time, a remarkable and very 
beautiful tree or shrub, which somewhat resembles the 
above-mentioned Corchi. It seems rare, for I found it 
two or three times only. The stem, branches, twigs and 
small thorns are of a greyish green ; it is without leaves, 
but the twigs are so finely divided, that from a distance 
it appears covered with delicate foliage ; twigs and 
thorns are covered with small red glands, containing a 
resin or oil, which is strongly scented, like a mixture of 
carraway, aniseed, and violets. The seeds, which were 
just ripe, were in pods, each containing one small bean : 
the pods are more thickly covered with the same red 
glands, and the scent is still stronger of aniseed than on 
the twigs. The ground was covered almost an inch thick 
with the dry flowers, of a dark violet, with the richest per- 
fume. When in blossom, the little tree must be remarkably 
beautiful ; its appearance altogether is exceedingly delicate 
and remarkable. The flower is papilionaceous. 
We now reached the plain through a rocky pass in the 
valley, forced open by the Gila. Here this stream unites 
with the Colorado, and we were now not far from Camp 
Yuma, a military station of the United States at the junc- 
tion of the two rivers. The bare, steep, and rocky hills of 
this pass are a kind of syenite, consisting of finely-grained 
dark-green amphibole, some mica, with quartz and felspar, 
partly white and partly rose-coloured, both minerals in 
separate masses included as in a porphyry. The rock appears 
rough, split and cracked, intersected in all directions with 
quartz veins of small dimensions. Different kinds of cactus 
grew upon it ; among them a delicate little opuntia, quite 
en miniature, and a beautiful small echinocactus, with 
straight white, and crooked black thorns. We proceeded 
