152 
GEOLOGICAL REPORT—THIRTY-FIFTH PARALLEL. 
rieure du Trias avec argile blanche et grise, 
epaisse, sans fossiles ; inclination an nord, 
beaucoup de drift de petits cailloux colores et 
pieces de bois petrifie. Dans le Rio Cbiquito 
on a des fossiles carboniferes roules, ce qui in- 
dique cette formation dans la Sierra Blanca et 
assez pres de nous. 
passing tlie inferior portions of the Trias, ■with 
red and blue and grey clays, thick, but with¬ 
out fossils ; inclination of these beds is to the 
north. There is much drift of little colored 
pebbles and pieces of petrified wood. In Rio 
Chiquito w T e found rolled carboniferous fossils, 
which indicate that this formation is found in 
the Sierra Blanca, and not far from us. 
-t 
6 Decembre.—Du No. 19 'au No. 20'.—On suit 
14 miles i la riviere Chiquito sur le cote droit, 
vallee large quelques buttes sur notre droite, 
Trias inferieur gres et marne rouge, et au- 
dessous des marnes blanches. Le diluvium 
venant de Mogoyon est nombreux a cailloux 
moyens; avec debris de Spirifer et Productus; 
surtout des silex gris. 
7 Decembre.—Du No. 20' au No. 21'.—On fait 
8 miles ; pas de changement geologique avec 
la marche d’hier. 
8 Decembre.—Du No. 21' au No. 22'.—On fait 
5 miles ; meme formation ; pas de change¬ 
ment. 
9 Decembre. — Du No. 22' au No. 23'.—On fait 
un mille et demi; pas de changement. 
14 Decembre. — Du No. 23 ' auNo. 24'.—On fait 
4 milles ; en traversant le Rio Colorado Chi¬ 
quito, Neio Pied avec gypse blanc en rognon 
epais. Diluvium nombreux tres-petit, avec 
quelques fossiles carboniferes. Productus semi- 
reticidatus et Polypi venant de la Sierra de 
Mogoyon. 
1G Decembre. — Du No. 24' au No. 25'.—On 
fait 11 milles en descendant la riviere tout le 
temps sur le Trias inferieur. Gres rouge, argile 
rouge et blanc. Diluvium nombreux, rnais 
avec petits cailloux. 
17 Decembre.—Du No. 25' au No. 26', 16 
milles. —En descendant la riviere, gres et ar¬ 
gile rouge du Trias inferieur, recouvert par du 
diluvium a cailloux tres petits, venant de la 
Sierra de Mogoyon. Les assises plongent tou- 
jours au nord sous un angle de 8 a 10 degres. 
On voit des buttes basaltiques a Test, est, 
nord, huit ou dix sur la plateau de Trias. 
December 6.— From Camp No. 78 to Camp 
No. 79.—We followed the Rio Chiquito for 
14^ miles, on right side. The valley is large ; 
some buttes on our right; Trias inferior ; red 
sandstone and marl, and white marl under 
them. The diluvium comes from the Mogoyon 
Sierra ; it is abundant, and contains pebbles 
of medium size, especially of grey silex, and 
also fragments of Spirifer and Productus. 
December 7.— From Camp No. 79 to Camp 
No. 80—(8 miles.) —The geology is the same 
as observed yesterday. 
December 8.— From Camp No. 80 to Camp 
No. 81—(5 miles.) —The formations continue 
the same, without change. 
December 9.— From Camp No. 81 to Camp 
No. 82, (1|- miles.) —No change in the geology. 
December 14.— From Camp No. 82 to Camp 
No. 83, (4 miles.) —In crossing the Rio Colo¬ 
rado Chiquito, white gypsum was seen in thick 
kidney-shaped masses in the New Red. Dilu¬ 
vium abundant and very small, containing car¬ 
boniferous fossils; Productus semi-recticulatus 
and Polypi coming from the Sierra Mogoyon. 
December 16.— From Camp No. 83 to Camp 
No. 84.—We made 11|- miles descending the 
river, and continually on the inferior Trias. 
Red sandstone and white and red clays were 
seen. Diluvium abundant, with small pebbles. 
December 17.— From Camp No. 84 to Camp 
No. 85, (16 miles.) —We were yet descending 
the river, and passed red sandstone and red 
clays of the inferior Trias, covered with but 
little diluvium, of very small pebbles, coming 
fronnthe Sierra Mogoyon. The strata all dip 
northward at an angle of from eight to ten 
degrees. We see basaltic buttes in the direc¬ 
tion of E.E.N.; eight or ten of them being 
on the plateau of the Trias. 
