RESUMfi AND FIELD NOTES. 
161 
tagnes qu’ hier semblant a une distance de deux 
milles du rio. 
23 Fevrier.—Du No. 69' cm No. 70'.—On 
traverse des collines et mesa de drift du quater- 
naire, la vallee va-[?] retrecissant des deux 
cotes du rio. On campc au pied d’ une mon- 
tagne d’ ou le rio sort. 
24 Fevrier.—Du No. 70' au No 71'.—Nous 
traversons une grande montagne contrefort du 
Cerbat. D’abord on a une roche rougeatre 
brune, qui est du trap amygdaloi'de au’a re- 
couvert le conglomerate, le gres rouge et l’argile 
crayeuse du tertiaire que 1’on voit non meta- 
morpbique dans la vallee le jour precedent. 
Puis on a de larges filons de porphyre rouge 
de quartzite, de trap, de gneiss, et enfin de 
granite vers Test; en revenant a la riviere on 
a de nouveau le conglomerat et l’argile blanche 
crayeuse metamorphique, La vallee s’elargit 
de nouveau et l’on a la vallee du Mojave. Ces 
montagnes sont extremement abruptes, a pics 
comme dans les Alpes ; hauteur au-dessus de 
la riviere de 300 a 1000 pieds. 
26 Fevrier.—Du No. 71' au No. 72', 10 
milles. —Au milieu de la vallee d’alluvion de 
terre noiratre du Rio Colorado des Mojaves. 
27 Fevrier. — Du No. 72' au No. 73'—On 
traverse le Rio Colorado. Pas de cailloux, tout 
de sable et de boue noiratre. Couleur del’eau, 
brun rongeatre. 
1 Mars. —Rien de nouveau. 
2 Mars.—Du No. 74' au No. 75'.—A 8 milles 
de distance, ou rencontre les roches quartzeuses 
eruptives de la premiere chaine Californienne. 
On la traverse ; elle a quartre milles de large, 
trap, conglomerat, metamorphique ; puis on a 
une large plaine inclinee, recouverte avec un 
peu d’alluvial, mais generalement des roches 
granitoides decomposees sur place. Pas d’er- : 
ratique. 
3 Mars.—Du No. 75' au No. 76'.—On finit 
de traverser la plaine inclinee et l’on penetre 
dans la seconde chaine de montagnes, ou il y 
a de l’eau courante. Cette seconde chaine est 
formee de conglomerat rougo metamorphique, 
21 t 
saw the same mountains, as yesterday, which 
appeared to be at the distance of two miles from 
the stream. 
February 23. —From Camp No. 129 to No. 
130. —We travelled hills and a mesa composed 
of drift, (quaternary). The valley becomes 
narrower, and we camped at the foot of a 
mountain by the river. 
February 24.— From Camp No. 130 to No. 
131. —We travelled over a high mountain—a 
spur of the Cerhat system. We at first found 
a reddish-brown rock which is amygdaloid 
trap, and which is covered by conglomerate, 
and also the red sandstone and the chalky clay 
of the Tertiary which we yesterday saw non- 
metamorphic in the valley. We then found 
large veins of red porphyry, of quartzite, of 
trap, and of gneiss, and finally of granite, 
towards the east. On returning to the river 
we again found the conglomerate and the 
white, chalky metamorphic clay. The valley 
again widens, and we found the valley of the 
Mojave river. These mountains are extremely 
abrupt, with peaks, as in the Alps. Height 
above the river from 300 to 1,000 feet. 
February 26.— From Camp No. 132 to Camp 
133, (10 miles.) —We travelled in the middle of 
the alluvial valley of the Colorado ; this allu¬ 
vium is black. 
February 27.— From Camp No. 133 to Camp 
No. 134.—We crossed the Colorado river ; no 
jjebbles; everything of sand and blackish mud; 
color of the water reddish-brown. 
March 1. —From Camp No. 134 to Camp No. 
135. —Nothing new. 
March 2. —From Camp No. 135 to Camp No. 
136. —At the distance of eight miles we met 
the quartzose eruptive rocks of the first Cali¬ 
fornia chain. We crossed this chain and found 
it four miles wide. Trap and metamorphic 
conglomerate were found ; then we found an 
extended inclined plain covered with a little 
alluvium, but generally with the debris of the 
granitoid rocks which decompose on the spot. 
No erratics. 
March 3. —From Camp No. 136 to Camp No. 
137. —We ceased to traverse the inclined plain 
and penetrated among the second chain of 
mountains, where there is running water. 
This second chain is composed of red meta- 
