142 
GEOLOGICAL REPORT-THIRTY-FIFTH PARALLEL. 
essous de Tejera. D’abord du Eio G-rande 
allant est on a pour 10 milles d’alluvions du 
It. M., puis avant d’entrer dans le canon deSan 
Antonio, on a des masses de granite gris noir- 
atre, a horneblende et gros cristaux de feldspath 
blanc quelquefois, jaunatre les masses de gran¬ 
ite ont 3 milles de large, puis apres le rancho 
habite, on a im granite rose, un pen de felds¬ 
path, et des dykes de granite blanc rosatre ; 
enfin un trap serpentineux vert, renfermant 
des assises calcaires metamorphiques de l’age 
Devonien ; et en contact avec cette roche verte, 
le calcaire de montagne ou lower carboniferous. 
Au Camp A on a la coupe suivante: 
below Tejera .—On going easterly from the Rio 
Grande, we travel ten miles on the alluviums 
of the Rocky mountains; then, before entering 
the canon of San Antonio, we found outcrops 
of blackish-grey granite, with hornblende and 
large crystals of white feldspar, sometimes yel¬ 
lowish. These exposures of granite are three 
miles wide. Then, after passing the inhabited 
ranchos, we have a rose-colored granite, with 
but little feldspar, and dykes of rosy-white 
quartz; finally, a green serpentinoid trap, con¬ 
taining strata of metamorphic limestone of 
Devonian age, and, in contact with this green 
rock, the Mountain limestone or Lower car¬ 
boniferous. At Camp A we have the follow¬ 
ing section : 
Le trap serpentineux est en contact avec le 
calcaire du carbonifere inferieur qui plonge 
a l’Est sous un angle de 35 a 40 degres, les 
tetes de couches regardant l’Ouest, et la direc¬ 
tion nord sud, un peu nord est de 3 a 5°. Ce 
calcaire est bleu grisatre, quelque fois noir, 
tres-compacte, a cassure conchoide, quelque 
fois se brisant facilement lorsqu’ il contient une 
lumachelle de fossiles. 
Quelques assises d’argile schisteuse, noire, 
tres-mince, sont intercallees. II y a 3,000 
pieds de ce calcaire, plus au sud, on dit qu’il con¬ 
tient des couches de houille grasses. Les fossiles 
ne sont pas abondants ni bien conserves, jai sur- 
tout recueilli les Productus giganteus et punc- 
tatus; un Spirifer et deux Terebratulce deux 
polypes, des massesdetiges d’encrinites formnat 
marbre-[?] plusieurs petits Productus, le 
Cora. Du Camp a Tejera pour un mille on a con- 
stamment, sur notre droite, ce calcaire carbon¬ 
ifere, puis au village on a de nouveau le Trias, 
avec toutes ses divisions ; derriere San Antonio 
pres d’Antonitto, on a le gypse blanc du Trias. 
Les couches plongent toutes a Test sous un 
angle de 20° a 45°. 
The serpentinoid trap is in contact with the 
limestone of the inferior carboniferous, which 
dips to the east at an angle of from thirty-five 
to forty degrees, the heads of the beds turning 
towards the west. The trend is north and south, 
or from three to five degrees E. of N. This 
limestone is greyish-blue, sometimes black; 
very compact, with a conchoidal fracture, and 
sometimes breaks easily when it contains a 
lumachelle of fossils. Some strata of very thin 
and black clay shales are intercalated. This 
limestone has a thickness of three hundred 
feet. It is said that a short distance further 
south it contains beds of bituminous coal. The 
fossils are not very abundant or well preserved. 
I gathered principally the Productus giganteus 
and punctatus, a Spirifer , and two Terebratulce 
and Polypi; fragments of the stalks of encri- 
nites forming marble-[?]; and many small 
Producti , the species Cora. From the camp 
at Tejera we have constantly on our right, for 
the distance of a mile, this carboniferous lime¬ 
stone, then in the village we again meet the 
Trias with all its divisions. Behind San An¬ 
tonio, near Antonitto, we have white gypsum 
of the Trias ; all the beds dip to the east at 
angles of from twenty to forty-five degrees. 
