Geological Survey Bulletin 612 Guidebook of the Western United States: Part B

SHEET No. 24. (click on image for an enlargement in a new window)

Antelope (see sheet 24, p. 218) is a few miles beyond Roseville. Beyond Ben Ali, a siding about 12 miles from Roseville, there is a tile and brick yard north of the track.

As it approaches Sacramento the train runs on an embankment, a part of a rather extensive system of levees which hold the flood waters of Sacramento and American rivers in check. After crossing American River the train skirts the north side of the city to the station, which is close to Sacramento River.

Sacramento, the capital of California, is on the east bank of Sacramento River 61 miles above its mouth, just below the mouth of American River. The city is on the low flood plain of Sacramento River, about 30 feet above mean sea level. It is a distributing point and wholesale center for the vast and fertile Sacramento Valley and has numerous manufactures, of which flour is the chief.

As boats drawing 7 feet of water can come up to the city, freight can be transported by water to and from San Francisco Bay. Electricity for lighting, for street railways, and for power is furnished by hydroelectric plants at Folsom, on American River, 22 miles away, and at Colgate, in the Sierra, on Yuba River, 119 miles away.

The first settlement on the site of Sacramento was a fort built in 1839 by John Augustus Sutter, a Swiss military officer in the service of Mexico. In 1841 Sutter was granted 11 square leagues of land by the Mexican Government, but the real history of the town begins with the discovery of gold in 1848. In December, 1849, the population was 4,000, and a year later it had increased to 10,000. The city was made the State capital in 1854. Before 1862 destructive floods were frequent, but since that date the city has been protected by levees. The lower portions of the main streams in the Sacramento Valley, overloaded with silt and, especially since 1849, with the débris from the placer mines in the Sierra, have built their channels above the level of the adjacent valley lands. Thus it has become of great importance to the farmers to confine the flood waters within the river channels, and to this end the banks have been raised by levees. There are many channels, usually dry, which lead out into the valley, particularly from the Coast Range. The flood waters of these channels can not reach the main river at all and therefore spread out over the lowlands on either side, to be eventually dissipated for the most part by evaporation. This accounts for the numerous areas of low marshy lands that border the river.

Leaving Sacramento the train crosses Sacramento River on a steel bridge and runs across flats which lie almost at tide level but which, being protected from inundation by levees, are cultivated as market gardens and for hay or grain. Farther west the land becomes marshy and is covered with a thick growth of tule (pronounced too'ly), a bulrush (Scirpus lacustris or californicus) which looks like a coarse, high grass. These marshes extend for miles on both sides of the track. In places the ground is slightly above the general level and its surface is covered with short grass used for the grazing of cattle and sheep. Beyond this country the train reaches slightly higher and better-drained lands, on which Swingle, a minor station, is surrounded by hay meadows and corn fields.

At Davis the Shasta and Overland routes join. The country in this vicinity is a smooth plain, near tidewater level, but nevertheless high enough to provide drainage. With its rich fields of grain and orchards, it has a distinctly prosperous look. Beyond Davis the Coast Ranges¹ become more prominent, especially to the right, ahead of the train, where one of them appears as a low dark ridge broken by one or more gaps. Valley and live oaks are again a common feature through the fields.

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¹Along the Pacific coast, from the vicinity of Santa Barbara on the south to Humboldt County on the north, rise the Coast Ranges, dividing the Great Valley of California from the ocean. These ranges are broken by the one great gap by which the combined Sacramento and San Joaquin rivers find outlet into the Bay of San Francisco. The Coast Ranges are geologically the most recent of the great structural features of the State. They are built up largely of folded and crushed Cretaceous, Jurassic, and Tertiary sedimentary rocks, which are in places broken through by andesitic and basaltic lavas and by older igneous rocks (diabase and other dark, heavy rocks, in part altered to serpentine).

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Dixon is an agricultural town in Solano County. Beyond it the Coast Range now looms larger as the traveler proceeds westward. Elmira (elevation 79 feet), a junction whence a branch road goes to Vacaville, Winters, and Rumsey, is next passed. Beyond Elmira the road approaches low foothills of the Coast Range—first a bare ridge with gaps through one of which the railroad passes over a slight rise. The factory of the Pacific Portland Cement Co. and adjacent shale quarries can be seen to the north. The limestone used here to mix with the shale is brought from a point near Auburn.

The traveler coming across the Sacramento Valley in the day during midsummer is likely to find the trip warm, but on reaching this gap in the Coast Range he almost invariably notices a change. The cool breezes sweeping in from the west and carrying the smell of the salt marshes become fresher as the train proceeds, and it is a reasonable precaution to have wraps handy from this point on.

Beyond the first spur of the Coast Range the valley again broadens. Higher mountains, more or less darkened by scrubby timber on their upper slopes, border the valley to the north and far to the south. If the air is moderately clear, Mount Diablo¹ and the southern continuation of the Coast Range may be seen. A group of low, round, and grassy hills a few miles to the south are known as the Potrero Hills. (Potrero, pronounced po-tray'ro, is Spanish for horse pasture.)

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¹From a point near Benicia, if the day is clear, an excellent view may be had of the double summit and graceful curves of Mount Diablo. Its general outline and isolated position have given the impression that this mountain is an old volcano. It represents, however, the higher portions of an overturned arch or anticline of sedimentary rocks thrust from the northeast toward the southwest. From its summit to the sea level at Carquinez (car-kee'nez) Strait is displayed a remarkably complete series of typical Coast Range formations, including Franciscan, Knoxville, Chico, Martinez, Tejon, Monterey, San Pablo, late Tertiary freshwater beds, Pleistocene, and Recent. Although Mount Diablo is of moderate height (3,849 feet), its isolation and its situation on the edge of the Great Valley make it one of the finest viewpoints in the State. From its top, on a clear morning, the summits of the Sierra Nevada can be traced for over 200 miles. Lassen Peak is often visible and sometimes Mount Shasta. The Great Valley appears divided into squares like a checkerboard by the section-line roads and fences. The San Francisco Bay region is sometimes hidden by a rolling, snowy sea of fog. The mountain is easily reached from San Francisco, though at present the actual ascent must be made on foot or by driving. It is expected that the road, which goes practically to the summit, will be fitted for automobile travel.

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Suisun (suey-soon', locally soo-soon', the name of an Indian tribe, said to mean great expanse) and the adjoining town of Fairfield (the seat of Solano County, population 834) are at the edge of another swampy district green with tule. From this point the railroad is graded across the Suisun Flats, which are so near tidewater level in Suisun Bay, to the south, that no cultivation is possible under present conditions, though the camps of several duck-shooting clubs are situated among the sloughs. The railroad formerly encountered much difficulty in maintaining its grade across this soft ground. Certain spots sank continually ever since the road was first constructed, and it was seldom that in going over this part of the route the traveler did not see work trains and grading crews busily engaged in filling and raising some sunken portion of the track. Mud ridges rose along the tracks on both sides, and their broken and lumpy surfaces indicated a slow flowing mass of mud squeezed out by the weight and vibration of passing trains. It is said that as much as 30,000 carloads of coarse gravel ballast was dumped into one of these spots.

Beyond the marshes the railroad meets the rocky headlands that here close in upon Carquinez Strait. Some fine exposures of Cretaceous and Tertiary sandstones and shales may be seen in the cliffs and road cuts around Army Point.

Near Benicia, on the left, is a United States arsenal and signal station. Benicia (named by Gen. Vallejo after his wife) is a manufacturing town with deep-water frontage. It contains, besides the arsenal, tanneries and other commercial establishments. Southeast of Benicia, across the strait is the town of Martinez, near which John Muir, California's great naturalist, lived for many years. The tall smokestack east of the town belongs to the smelter of the Mountain Copper Co., which mines its ore near Kennett, in Shasta County. At this smelter sulphur fumes are utilized in making sulphuric acid, which in turn is used in treating rock phosphate brought from the company's mine near Montpelier, Idaho, and here turned into fertilizer. Just beyond Benicia the train is run onto a ferryboat and is carried across Carquinez Strait to Port Costa, a distance of a mile.

The geologic section from Benicia and Port Costa to the vicinity of Berkeley and Oakland is particularly interesting, as in it are represented many of the characteristic sedimentary formations of the Coast Range. This stratigraphic section is quite different from that of corresponding age in the Sierra foothills.