104 GUIDEBOOK OF THE WESTERN UNITED STATES. 
At Gallup a large supply of excellent water is obtained from artesian 
wells sunk through the coal-bearing rocks into the underlying sand- 
stones. Without this underground supply the town would be greatly 
hampered, for the surface waters in the vicinity are very small in 
volume and mostly of bad quality. The well water is carried in tank 
cars to supply many stations along the railway where the local water 
is not satisfactory. 
A coal mine, plainly visible a quarter of a mile north of the track a 
mile west of Gallup, is one of the large producers of the area. Just 
south of a point two-tenths of a mile beyond milepost 163, west of 
West Yard siding (see sheet 16, p. 108), is a knob due to a mass of 
dark igneous rock (vogesite), cutting the coal-bearing rocks, and 
another small dike of the same material appears half a mile farther 
southwest. 
At milepost 163 sandstones below the coal measures appear, and a 
short distance north of milepost 166, which is at Defiance siding, they 
arch over, forming a well-marked anticline. Beyond this arch the 
beds dip west for a short distance at moderately steep angles, into a 
shallow syncline, out of which they rise again on an easterly dip at 
milepost 167. The easterly dip continues for some distance, bringing 
up lower and lower beds of the sandstone in succession toward the 
west. Finally at milepost 176 appears one of the lower sandstones, 
200 feet thick, forming a high wall on both sides of the Rio Puerco 
valley, which in consequence becomes a canyon. These cliffs con- 
tinue for several miles to the west. 
At Manuelito (mahn-way-lee’to) considerable trading is done with 
the Navajo Indians who live on the reservation a short distance 
north. This place was named for a Navajo who 
Manuelito, N. Mex. was elected chief in 1855, when a treaty was 
— a 00 fet arranged with the Navajos to end their depreda- 
Kansas ity 1,095miles, tions. This treaty, however, was not ratified by 
Congress, and lawlessness continued till the final 
subjugation of the tribe eight years later. Subsequently ‘Manuelito 
was made head of the native police force and proved loyal to the 
Government. 
Two-tenths of a mile beyond milepost 179 the State line is crossed 
and Arizona is entered. The State line is on the thirty-second 
meridian west of Washington (about 3 miles west of longitude 109° 
west of Greenwich) and was so defined by law at a time when the 
‘ The first wells at Gallup were not very | advice and important water supplies 
deep and obtained only a moderate vol- | obtained. The study of the conditions 
ume of water, but on the advice of a geolo- | under which waters occur underground is 
' gist of the United States Geological Sur- | a branch of geologic investigation requir- 
vey deeper borings were made with great | ing the determination of the successiOD 
success. Several other wells have been | and structure of the water-bearing rocks 
sunk at places on this railway on similar | and their associated beds. 
