SOUTHERN PACIFIC LINES 177 
Brigham Young in 1878. These settlers founded St. David. It was 
down the San Pedro Valley in 1846 that Colonel Cooke laid out the 
military road to the West that was used extensively by later travelers. 
His troops were made up largely of Mormons who entered the service 
in order to reach California, where their term of enlistment would end. 
The railroad reaches the bottom of the San Pedro Valley at Here- 
ford and follows it northward to Benson. Near Hereford and for 
some miles north the prominent’ Huachuca Mountains 
ma ect, (Wah-choo’ca) form the west side of the valley, 
sulation2ai, attaining an elevation of over 9,000 feet in Miller 
Peak and Carr Peak. It is included in a division 
of the Coronado National Forest. At its north end 
is Fort Huachuca, a frontier military post reached by a 13-mile 
branch railroad from Lewis Springs. 
The San Pedro Valley is from 15 to 20 miles wide in greater part, and 
with steep lateral slopes and a declivity of nearly 600 feet in 40 miles it 
is very different in character from the basinlike 
Sulphur Spring Valley, which lies a few miles east. 
Elevation 4,027 feet. 
New Orleans 1,453 This difference is due to the erosion of a vigorous 
miles: river which trenches deeply into the thick valley fill, 
especially in the region below Lewis Spri At Lewis Springs and 
at intervals northward porphyry is revealed in the valley bottom, 
which is apparently on the crest of an underground ridge connected 
with the porphyry area so extensively exposed about Tombstone. 
This noted mining camp lies 8 miles east of the main railroad and is 
reached by a branch line from Fairbank, where there is also a branch 
railroad leading to Patagonia. 
Tombstone is on the gentle slopes of the Tombstone Hills, overlook- 
ing the San Pedro Valley. The ore deposits ** were discovered by 
Ed. Schieffelin almost by accident in 1878, the great strike occurred 
in 1879, and the town was established in 1881 with the name Tomb- 
New Orleans 1,443 
miles. 
Lewis Springs. 
stone because someone predicted 
to Schieffelin that his prospecting 
34 According to Ransome the Tomb- | 
stone mining district presents a local 
uplift of Paleozoic rocks lying on a base- 
also larger 
masses of granitic rocks and porphyry 
that cut all the strata, causing consid- 
erable metamorphism, which appar- 
ently had much to do with the deposi- 
tion of the rich silver ores in the lime- 
stone. The basal strata are 440 feet of 
limestone i 
above are 340 feet of Martin limestone 
(Devonian), 500 feet of Escabrosa ne 
stone (Mississippian), and 2,000 
3 ,000 feet of Naco limestone ee 
vanian and Permian). There is much 
faulting. The greater part of the silver 
ore was found in the limestone of the 
overlying Comanche series, partly as 
replacement deposits in the limestone 
deposit in the Naco 
