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• precipitation. Less than average annual precipitation may produce <br />a lowering of the local piezometric surface. Wells in the Trinidad <br />produce from near the bottom of the sand and low yields are reported. <br />There are no data on the artesian or non-artesian nature of the <br />Trinidad aquifer beneath the permit area. It can be estimated that <br />the potentiometric surface will increase towards the east permit <br />boundary where over burden thickness is greater. <br />In the Trinidad, Colorado area the quality of water is poor <br />to fair.l Use is primarily for livestock. <br />Vermejo Formation <br />Conformably overlaying the Trinidad sandstone is the Vermejo <br />Formation. This unit consists of interbedded carbonaceous shales, <br />thin lenticular sandstones and as many as twenty individual coal <br />beds. The coal varies from a few inches to greater than 10 feet <br />• in thickness. Sands within the Vermejo are coarser grained than <br />the Trinidad sands and are cemented with silica. Localized lenses <br />of ironstone (iron carbonate) occur throughout the formation. <br />Because of this, weathered outcrops are often limonite stained. <br />Formation thickness averages 200 feet in this area, and dips at <br />less than one degree to the west. <br />In some areas fractures associated with dikes cause channels <br />for introduction of water into the coal seams and sands. Minor <br />faulting is also known in the area, as observed in the mines. <br />Although the coal beds and associated sands transmit water, no <br />known dewatering problems have occurred in mines of this~area.2 <br />1Communication with Mr. R.L. Watson, Soil Conservation Service, <br />U.S. Dept. of Agriculture, Trinidad, Colorado. <br />2Communication with Mr. Haske, Colorado Division of Mines, Denver, <br />Colorado. <br /> <br />FISHER, HARDEN 8 FISHER <br />121 <br />