SOUTHERN PACIFIC LINES 225 
The low range of buttes rising abruptly from the plain a few miles 
north of Casa Grande and extending thence westward are the Sacaton 
Mountains, which consist of massive light-colored granite (mica 
diorite). There is a small knob of this material 3 miles northeast of 
Nufiez siding, and it appears in many of the ranges to the north and 
west. It is an intrusive rock which has been forced up in molten 
condition through the old schist in pre-Cambrian time. 
At the small station of Maricopa is the branch’ line to which 
formerly passengers for Phoenix were transferred. Now, however, 
as explained on page 224, most of the trains go directly 
to Phoenix from Picacho. Maricopa is situated on a 
broad desert plain not far from the Santa Rosa Wash 
— Orleans 85 and the Santa Cruz River, both of which are generally 
dry. In this vicinity clierd is a small amount of 
irrigation by water pumped from wells. Many mountains rise 
abruptly from this plain, the Sierra Estrella to the north and the 
Palo Verde Mountains to the west, which are continued southward 
by various ridges of schist and granite to the high Table Top Moun- 
tains, 25 miles south of Maricopa. This range, which does not appear 
distant, culminates in a flat-topped peak that has an elevation of 
nearly 4,000 feet and consists of a cap of basalt presenting steep 
cliffs on all sides. Some distance northwest is the steep conical 
summit known as Antelope Peak, composed of a sheet of lava dipping 
at a steep angle. Below these lavas are granites and schists rising 
to an irregular plane which in Tertiary time was a general surface on 
which the lavas were poured out. Subsequent uplift, tilting, and 
erosion have left the remnants of the lava flows perched high above 
the general desert level, a feature which is general in a large part of 
southwestern Arizona. 
West of Maricopa the railroad ascends slightly to reach at Enid 
siding the wide pass between the Sierra Estrella on the north and the 
Palo Verde Mountains on the south. The Sierra Estrella is a very 
prominent range which extends 25 miles north to the mouth of the 
Salt River, with an average width of 3 miles and a maximum height 
of about 3,000 feet above the plain. Montezumas Head, at the south 
end, has an elevation of 2,406 feet. The siorthéastery front of the 
range is very steep and rugged up to about 2,000 feet, where some 
of the canyons open into valleys. The range consists mainly of 
schist, but this rock is invaded by large intrusive masses of granite, 
one of which at the south end extends nearly to the railroad. A 
Maricopa. 
ee 1,175 feet. 
mn 30.* 
(Devonian) and Carboniferous lime- | brian . The overlying limestones 
stones. The Abrigo beds at this place | (Martin) carry abundant Upper Devo- 
consist of slabby brown sandstones, in | nian fossils that indicate an extension 
part glauconitic (greensand), with | of the sea waters of Paleozoic time over 
brown and gray shales. They contain | much of western Arizona. 
worm markings and lingulas of Cam- 
* 
