Page 717 - calmining1890

SOLANO COUNTY. 667
;.wo hundred and fifty feet in depth, along the northern portion of the
island. In these, thick strata of yellow clay were passed through, as
was the case in the three hundred-foot well. Below a depth of one
lundred and seventy -five feet, a good supply of potable water was
bbtained in strata of fine gravel and brown sand, which were inter-
stratified with the yellow clay. Above a depth of one hundred and
seventy-five feet the water was either salt or brackish. Blue clay was
-struck* in some of the deeper wells. No organic remains were noticed
in the sand among the yellow clay; but in the blackish sands, yield-
ing water in the first two wells, fragments of " willow" wood were found.
One prominent landmark in this part of Solano County is a high hill
locally known as Mount Bronson, which rises between the main chain
of the Montezuma and the Potrero Hills. This eminence, which is sit-
uated on the Lindo Ranch, appears to be largely formed of sandstones,
and in one or two places the white, friable sandstone, light-colored clays,
and shaly strata of the coal measures make their appearance. The dip
of the formation is to the northwest.
The summit of the hill commands an extended view and affords a
very comprehensive idea of the course of the ancient water channel, and of
the erosion which has given the present contour to the surrounding land-
scape. To the southeast are the rounded Montezuma Hills, whose gentle
slopes upon the south terminate in long swales, the tapering points of
which stretch out into the " tule" lands bordering the Sacramento River,
while upon the north the hills descend in rolling lands towards Maine
Prairie. From this point looking eastward, the erosion between Mount
Bronson and the Montezuma Hills is very distinctly seen; to the west
curves Nurse's Slough, which connects Denverton with the Sacramento
River, and cuts off the Potrero Hills from Mount Bronson, leaving that
eminence, with two or three smaller hills, like islands in the " tule." Upon
the Lindo Ranch a good supply of water is obtained at a depth of about
thirty feet, and the following formation has been observed in boring:

Character of Strata. Thickness of
Strata, in feet.
"Tule," clayey soil, and mud. 10 to 12
Yellow clav ... 15 to 20

Beneath the yellow clay is gravel and dark-colored sand, which is
usually penetrated a few feet, and yields a good supply of water. Fol-
lowing Nurse's Slough to Denverton, water is struck at a depth of from
six to twelve feet, but it is unfit for use. Good water is, however,
obtained in veins in the sandstone at a depth of thirty to forty feet.
Throughout the valley land, between Denverton and Suisun, the soil
varies from an adobe to clayey and sometimes sandy loam; the surface
water is struck at a depth of ten to fifteen feet, and in many places less.
Around Suisun and Fairfield the wells are from twenty-five to forty
feet in depth; the surface soil is "adobe," which extends to a depth
of fifteen to twenty feet, beneath which is a gravel which yields a
good supply of water, but it is somewhat hard; beneath the gravel is a
tough yellow clay. Suisun and Fairfield are suppled with water from a
dug well about thirty feet deep, which is situated a short distance to the
west of the county seat; also, by numerous private wells.