Art. V.] Herrick, Geology of New Mexico. 105 
as Productus cora, Spirifer opima, Martinia concentrica, etc. 
The section is about as follows : 
Phrst, 225 feet of dark, bedded limestone, followed by 50 
feet of shales, then 150 feet of gray massive limestone on 
which reposes about 25 feet of reddish or yellowish sand-stone. 
Then follows 100 feet of limestone with a thin bed of shale and 
a few feet more of lime making up an additional twenty feet. 
Then follows 25 feet of sand stone and 25 feet of lime to the 
top of the exposure. Carboniferous fossils may be found to 
near the top though it is possible the very upper portions may 
contain representatives of a Permean fauna. It will be noted 
that this section contains sand-stone members near the top not 
seen in sections apparently as complete further east. It is prob- 
able that the present section actually reaches higher levels than 
the latter and that a certain part of the limestone series is be- 
low the present section and is to be added to the total thickness. 
Passing eastward the strata become practically horizontal 
and the country more level. The fault line between the Car- 
boniferous and the Jura-triassic is well seen at the little town of 
De Vaca about two and a half miles east of Tijeras. The lime- 
stone and the sands of the Triassic both dip to the northwest 
but in no place were the two seen in conformity. At this place 
it is the upper part of the Carboniferous that emerges and it is 
here filled with bryozoa and a narrow horizon is distinguished 
by being almost made up of small foraminifera of the genus 
Fusulina. 
The Carboniferous extends eastward and apparently covers 
the entire rolling country to the valley occupying the east- 
ern part of the sheet. At Sedillo it is well exposed and is still 
nearly horizontal. Further northeast it seems to be uplifted so 
that the underlying quartzites are exposed two miles northeast 
of Sedillo. This area is covered with a sparse growth of cedar 
and pinon and seems to be available farm land where ever irri- 
gation is possible. 
An irregular line extending north and south along the east- 
ern third of the sheet is the axis of uplift occupied by the 
mountains of the San Pedro group, which are, beginning at the 
