158 GUIDEBOOK OF THE WESTERN UNITED STATES 
veins at or near the contact of an igneous intrusive mass (monzonite) 
with limestone of Abrigo to Martin age at the north end of the 
Dragoon Mountains. These mountains extend south from Dragoon 
Pass to and beyond the mining settlements of Courtland and Glee- 
son and contain many small mines and prospects. Thegeneral struc- 
ae 
PB Vi alscl 
bh 
Horrzentet scale ; 
° 2 Miles 
j 
Vertical scale 
4000 Feet 
ORE he 
Figure 37.—Sections across the Dragoon Mountains, Ariz. Upper section, 3 to 6 miles southwest of 
the railroad; lower, 12 miles southwest of the railroad 
ture of the northern and medial portions of this range is shown in 
Figure 37. 
Some of the limestone on the west slope of the central ridge has been 
altered to marble by igneous intrusions, and this rock has been quar- 
ried in small amount in the slopes 3 miles southeast of 
Siewons Dragoon. In the higher part of the limestone suc- 
Panda: cession in the north end of the Dragoon Mountains 
bests ay 1,430 is a member of red sandstone and much coarse lime- 
stone conglomerate containing boulders of limestone 
and sandstone. 
_ North of Dragoon are the high hills and ridges of the Little Dragoon 
Mountains, in which is situated the small mining settlement of 
Johnson, a copper producer for 45 years. The southern part of this 
range has a rough surface of knobs of granite, mostly of very coarse 
16 The Dragoon Mountains consist | many large detached —— of — 
largely of granite, | limestone are included in 
which euts across the Pinal schist 
(Archean), Bolsa quartzite (Cambrian), 
Abrigo limestone (Cambrian), Martin 
Tmestone step limestone of 
sandstone and 
shale of eum eee i age. Small 
The eastward-dipping thst suc- 
cession in the north end of the range, 
with a thickness in excess of 2,000 feet, 
is mainly Naco limestone (Permian and 
Pennsylvanian). Abrigo limestone and 
the underlying Bolsa quartzite on Pinal 
schist are in sl mil 
southeast of Dragoon station, with the 
relations shown in the upper section in 
Figure 37. 
and 
