536 BONES OF DESTKOYED HEEDS. Book III. 
ephedra, and a few miniature annuals. The storm of 
the preceding day had filled a brook running through 
these ravines of gypsum, with copious water, by which 
we rested for a few hours. I do not know whether this 
brook is permanent or temporary, or whether or no it 
belongs to the Carrizo Creek. Throughout this whole 
region — from the edge of the desert plateau through the 
gypsum ravines, as far as Carrizo Creek — the ground is 
strewn with the bones and skeletons of thousands of sheep, 
cattle, mules, and horses. The reader may form an idea 
of this scene, from the fact, that of a single flock of sheep 
proceeding the year before from Northern Mexico to Cali- 
fornia, six thousand lay dead on this spot. Many of the 
dying animals appear to have crept in the pains of death 
into holes and corners among the wildest rocks. I found 
in these places numbers of skeletons wedged into almost 
inaccessible corners and narrow fissures. 
I have heard various opinions respecting the extraor- 
dinary mortality among animals driven from the Colorado 
across the desert, especially on the Carrizo Creek, — a 
watering-place against the dangers of which we were 
strongly cautioned. Some asserted the waters to be poi- 
sonous; others thought the circumstance of drinking too 
freely after a long thirst, offered sufficient explanation of 
the fatal effects ; while others attributed them to cer- 
tain plants growing in this neighbourhood, which are only 
eaten by animals when suffering extreme hunger. The 
plant pointed out to me as poisonous, was a small euphor- 
bia covered with a grey film, which might justify this 
supposition. Another opinion appeared quite natural, 
that on approaching the termination of the desert the 
strength of the animals, exerted to the utmost by toil, hun- 
ger, and thirst, should at last give way. Probably the truth 
