The Fundamental Complex—Key es. 1 19 
northwesterly and southeasterly direction through the 
Turkey mountains. The genesis of this arch is probably of 
quite recent date. It crosses the great fault that runs along 
the eastern front of the Rockies which late erosion has 
greatly obscured at this point. 
The Azoic core of the Las Vegas and Mora ranges 
forms a narrow belt which begins a few miles north of the 
crossing of the Pecos river by the Atchison, Topeka and 
Santa Fe railroad and extends northward a* distance of 65 
miles. It is bordered on each side by wide belts of Carboni- 
ferous limestone. The most prominent peak is Solitario, 
which rises to a hight of 10,260 feet above sea-level. 
At the northern extremity, the rocks appear to be al- 
most entirely hornblende schists. A few miles to the south- 
ward light colored micaceous schists and gneisses are the 
prevailing rocks, with some dark colored gneisses occupy- 
ing the central portion of the belt. At Mora the principal 
rock is a gneissic granite, while farther on appear again the 
micaceous schists. From the Cebolla canyon the gneisses 
and schists appear to be profoundly affected by deformation 
agencies. From Solitario peak southward the predominant 
rock is a coarse-grained granite with occasional bands of 
gneiss. 
The east side of the Rio Grande valley in northern New 
Mexico is bordered by the lofty Santa Fe mountain range, 
the highest peak of which, known as Baldy, is 12,660 feet 
above the sea-level. The central axis of this range is com- 
uosed of ancient crystallines bordered on each side by Car- 
boniferous rocks. The crystalline belt is 50 miles long, by 
6 to 8 wide in the broadest place. At the southern end in 
the Apache canyon the prevailing rock is a red granite. 
Granite bands and masses appear at frequent intervals far- 
ther north in the gneisses and micaceous schists. In the 
Santa Fe canyon there occur in the gneiss bands of argilla- 
ceous slate. Farther north the rocks present similar geolo- 
gical characters. 
Archaean granites are reported by Stevenson as com- 
posing the Placer (Ortiz) mountains, 20 miles south of San- 
ta Fe. No granite is found in these mountains. The rocks 
are micaceous and augitic andesites of laccolithic origin. 
