MARICOPAS AND PIMAS PLAINS. 
137 
Fig. 3 also represents the disposition of the Jornada viewed in section. 
Descending the eastern slof)e of these hills the plains of the Maricopas wells are reached. 
These are flats on each side of the Grila, above its junction with the Salinas river. The river 
flows through these plains, which are broad and well supplied with coarse grass. At the point 
termed the Maricopas wells, which are several holes dug 7 feet down, and in which the water 
rises within 2^ feet to the surface, the soil is clayey and retentive, each well being a small 
body of water resting on yellow clay; when the well is emptied it fills in very slowly, the water 
at this season being slightly saline. The influence of this body of subterranean water is 
marked by the difference of vegetation, which, as soon as the hill slope commences, ceases to 
hear grass, rushes, canchalagua, and mesquite, and in their stead appear the fouquieria, 
prickly pear, and pitahaya. The valley of the Grila river is here very wide and the bottom a 
fine sandy (granitic) clay, very light in color, and only fertile where watered by sequias of 
the Pimas, when it produces abundantly. 
On each side of the river the Pimas cultivate the low land, where the sand and fine clay 
has a darker tint, from the presence of a small quantity of humus ; it is, however, a mere trace, 
and at the Maricopas wells is not more than half an inch thick, as shown by digging the fresh 
soil near the springs. Portions of the soil of the cultivated land of the Pimas, and of the soil 
upon the mesa, above the line of grass at the Maricopas wells, were collected and submitted to 
chemical analysis ; the results are given in the chapter devoted to that purpose. There does 
not appear to be any difference between the mineral character of the two soils ; the texture 
differs, that of the cultivated land being alluvial, and more quartzose. 
The cultivated ground of the Pimas is fenced around, each field being small, scarcely 150 feet 
each way ; a sequia runs around half a dozen fields, giving off branches to each. Corn, cotton, 
pumpkins, melons, and squash, were the chief articles of cultivation. A small portion only of 
the valley is under cultivation, being that along the river hank ; but it is susceptible of 
being made productive much further away from the stream. It is on irrigation only that a 
secure crop can be depended on, and as the Grila has much less volume here than below, where 
it receives the Salinas, occasionally the river bed is completely drained by the sequias. More 
care and economy in the use of water would he necessary under a greater breadth of cultivation. 
The immediate river bottom is here between six and eight miles across ; the mesa land is not 
more than seven feet above this level, and slopes back, in every direction, very gradually to the 
mountains, which are at six, eight, and twelve miles distance. The altitude of the Pimas lands 
near their villages is a little above 1,100 feet above sea level, which, combined with the prox¬ 
imity of long mountain masses, caused the deposition of dew at night, the first which had 
been experienced since leaving Yallecitas ; it was quite copious when passing the Jornada to 
reach these plains. 
Leaving the villages to the west, after a few miles travel, low spurs of a range coming in 
from the southeast are met with. These consist of protogine and talcose slate ; on the north side 
of one small hill, near the trail, fine-grained gneiss was observed, dipping 35° west; still further 
east the trail strikes the river twelve miles east of the villages. On the mesa the soil is a felspar 
and granite debris ; near the river it is a fine sandy clay, similar to that of the Pimas lands. 
On the river, at this camp, (July 3,) the trails diverge ; the well-beaten ones are turning away 
southeastward, over the elevated table land, which stretches out without any apparent limit 
into Sonora, toward Tucson ; the uniform level being here and there only disturbed by an occa¬ 
sional low hill of felspathic granite or protogine. Along these trails the wagons and main party 
18 U 
