San Benito County History

This section is excerpted from A Memorial and Biographical History of the Coast Counties of Central California by Henry D. Barrows and Luther A. Ingersoll, and published by The Lewis Publishing Company in 1893.

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Coal.

Valuable discoveries of coal have been made in numerous localities in San Benito county; as in the New Idria, Vallecitos and other districts. A variety of coal resembling jet has been found near Elkhorn, and good coal prospects are to be found on the Cienega Gabilan (Hawk swamp or marsh) ranche. The coal-bearing formations at Emmett were worked as early as 1878. The Bart coal mine, situated about 1,000 feet above the roadway north of Emmett, is developed by an incline and a cross-cut at the upper working and a 100-foot tunnel lower down. The incline commences on a small vein about three inches wide of black, lustrous lignite, much of which shows a woody structure. The working itself is in clay slate, of which both hanging and foot walls are composed. The pitch of the vein is to the northwest at an angle of about twenty degrees. At one place, about halfway down the main incline, the vein pinches out, but reappears shortly before reaching the crosscut, which is at a depth of about thirty feet. The main incline is continued for about sixty feet farther, but has now caved. The cross-cut is continued to the west as an incline and follow the vein, which is from two to six inches in thickness. This cross-cut was filled with water to within a distance of thirty feet from the main incline. At the water's edge the vein is about six inches in diameter. Eighty feet below the mouth of the upper working is a tunnel, which has been started to connect with the incline and drain the upper workings of water. In this tunnel slate or conglomerate is encountered with small crystals of gypsum on the cleavage surface of the hard slate passed through.

On Panoche creek, also upon the east side of the roadway, to the west of the well of the California Central Oil Company, some work has been done in the way of development. There appear to be three coal veins separated by strata of light-colored sandstone. These veins, the largest of which are over four feet thick, are composed of shale interstratified with seams of coal.

On the Ashurst ranch in the Vallecitos, are several coal prospects, -- probably a continuation of the coal measures which crop out on the east side of the road near the central oil well. The formation is sandstone, occasionally interstratified with shale; in the upper portion of the hills is a fossiliferous sandstone containing Pecten and other shells. The coal measures are exposed at two places on this ranch in the channels of the creek. At one point the vein is about eighteen inches wide and dips a little to the east of south at an angle of about forty-five degrees. It is composed of black fissile shale mixed with carbonaceous matter and rests upon a stratum of clay about six inches thick, showing carbonized plant remains; above the coal is a stratum of highly colored clay. In another portion of the same creek other veins are exposed. Crossing the New Idria section of the coast range, which here rises to the height of about 4,000 feet above sea level, the watershed of San Benito creek is reached.

On the western slope of the mountains, about three miles northeast of the creek, a large vein of coal is exposed. This vein was uncovered by a landslide, which occurred during wet weather in 1885. It is on the northern side of a ravine in the western slope of the New Idria section of the coast range. The vein of about six feet in thickness is exposed along its strike for a distance of 100 feet, and dips to the north at an angle of about forty degrees. The hanging-wall is a brownish shale, eighteen inches thick, containing gypsum. Above this wall are about eight inches of sandstone, stained with yellow ocherous impregnations, which is overlaid by a stratum of hard, ferruginous sandstone, a foot or more in thickness; and from that to the top of the bluff, probably 200 feet, the formation is a gray, friable sandstone, interstratified with pebbles, sometimes increasing to the size of small boulders and strata of hard, iron-stained sandstone a few inches in thickness. The coal appears to be of good quality, and resembles that in the Vallecitos. These croppings are partly on Government land and partly on land belonging to the Southern Pacific Railway Company. There is no doubt that a careful investigation will discover similar formations in other spurs and hills on the western slope of the same mountain.

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This section is excerpted from A Memorial and Biographical History of the Coast Counties of Central California by Henry D. Barrows and Luther A. Ingersoll, and published by The Lewis Publishing Company in 1893.