RESUMfi AND FIELD NOTES. 
157 
mesa au nord de nous. Sur ce gneiss se trouve 
un gres Tertiaire plongeant a l’ouest surmonte 
d’une’espece de poudingue crayeux epais de 
15 a 20 pieds, corrode par l’eauatmospherique 
en petits trous. Ce poudingue parait etre 
un-[?] de cendre volcanique, conglom- 
erat de nombreux fragments de lave non rou- 
les. Puis trois milles du Camp No. 50', on 
rencontre deux cliaines granitiques rouges al¬ 
lant du sud au nord. Au nord on a la mesa 
carbonifere qui le termine, et l’on a les petites 
collines granitique, au sud le grand volcan 
Whipple mount- [?]; il est tres-large, 
peu eleve, et s’entre mele avec le granite. 
31 Janvier.—Du No. 50' au No. 51'. Peu 
apres etre sorti du Camp 50', on monte une 
colline qui est de la lave recouvrant le granite. 
Cette lave s’etend sur de vastes etendues au 
nord et a l’ouest a cinq milles du Camp 50', 
dans un rio, on a des assises de sables et de 
calcaire grossier, tertiaires inclinant fortement 
a l’ouest, la direction de dislocation etanfc du 
sud au nord. On a parmi des dykes de trap et 
de porphyre rouge. Pas de diluvium. Pays 
montagneux et difficile au point de vue geolo- 
gique. 
1 Fevrier.—Du No. 51' au No. 52'.—Au 
sommet de Cactus Pass, on a un large filon de 
sienite rouge, allant N.S. ; puis du gneiss, 
porphyre quartzifere, veines de quartz blanc. 
Le gneiss est contourne, les schistes p ongent 
a l’ouest. Au Camp 52' on a, a l’est, les 
montagnes Aquarius, avec plateau de conglom- 
erat de lave, avec mesa de laves. Pas de dilu¬ 
vium 
4 Fevrier.—Du No. 52' au No. 53', on fait 11 
milles f.—La moitie sur le granite avec quelque 
veines de quartz, moitie sur le diluvium. 
5 Fevrier.—Du No. 53' au No. 54'.—Le 
granite affleure de temps a autres sur la gauche, 
quoique souvent le drift le recouvre, le drift 
gneiss, which extends to the base of the mesa 
at the north of us; upon this gneiss is found a 
Tertiary sandstone dipping to the west, sur¬ 
mounted by a thick pudding-stone, from 
fifteen to twenty feet thick, and which is 
very chalky, and much corroded into cavities 
and little holes by the action of the atmosphere 
and water. This pudding-stone appears to be 
a mixture of volcanic ash, conglomerated with 
numerous fragments of lava, not worn by roll¬ 
ing. Then at Camp No. 109, we found two 
granitic chains trending north and south. On 
the north we find a mesa of carboniferous rocks 
which comes to an end, (“le termine”) and 
we find small granitic hills. At the south the 
great volcano, “ Whipple Mount ” is still seen. 
It is very large and but little elevated, and is 
intermixed with granite. 
January 31 .—From Camp No. 109 to Camp 
No. 110.—A short distance from Camp No. 
109, we ascended a hill which is composed of 
lava covering granite. This lava extends for 
great distances on the north and west. At five 
miles from Camp No. 109, we found, in a river, 
beds of sand and of coarse limestone, Tertiaries 
inclining strongly to the west; the direction of 
the dislocations being north and south. We 
found dykes of trap and red porphyry travers¬ 
ing the formation. No diluvium. The coun¬ 
try is mountainous, and difficult in a geological 
point of view. 
February 1 .—From Camp No. 110 to Camp 
No. 111.—At the summit of Cactus Pass, we 
found a large vein of red sienite trending north 
and south ; then gneiss and quartziferous por¬ 
phyry, and veins of white quartz. 
The gneiss is contorted ; the schists dip to 
the west. At Camp No. Ill, we found at the 
east the Aquarius mountains, with a plateau 
of lava conglomerate, and a mesa of lavas. No 
diluvium. 
February 4 .—From Camp No. Ill to Camp 
No. 112, (Ilf miles .)—Half of the distance 
traversed to-day was upon granite, containing 
some veins of quartz, and the other half was 
upon diluvium. 
February 5 .—From Camp No. 112 to Camp 
No. 113.—Granite appears now and then upon 
the left, although it is often covered by drift. 
