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• <br />gas exploration (d). An unpublished report by the U.S. Geological <br />survey reportedly describes a few domestic wells tapping the Trinidad <br />Sandstone near the Arkansas River, approximately 9 miles north of the <br />Permit Area (e). These wells have yields ranging from to 20 to 100 <br />gallons per minute and are less than 200 feet In depth. No further well <br />data is available, but the proximity to the Arkansas River aiiwlum <br />would Derhaps explain the unusually high yields. No mention of artesian <br />pressure head was made In the report, and not water quality sampling was <br />reported. <br />The Trinidad Sarxlstone was deposited during a northeastward <br />regression of a late Cretaceous sea Cd). This resulted in a northwest - <br />southeast linear orientation of the strandline sands within the <br />formation, and probably a higher aquifer transmisslvlty In the direction <br />parallel to the ancient shoreline. No pulp test data Is available, and <br />• the top of the Trinidad, is expected to be 300 to 400 feet below the area <br />to be mined Ca). <br />VermeJo Formation - The VermeJo Formation Is the primary <br />coal-bearing unit in the basin, and is 400 feet thick near the center of <br />the Permit Area. It varies from a coarse-grained cross-bedded sandstone <br />with a clay matrix to a fine-grained Indurated mid or siltstone (a). <br />Eleven identifiable coal seams are present In the general area, many of <br />which are nay being mined or have seen mining activity during the last <br />75 years. Total thickness of the Verme)o Formation in the synclinal <br />basin varies from approximately 900 feet near the axis to zero at the <br />Trinidad Sandstone outcrops surrandirg the basin. <br />Sandstones and shales separating the coat units are highly <br />lenticular, making it difficult to Identify a potential mini-aquifer in <br />the event one was present. The Hydrology Map, sheet 3 shays drill logs <br />and a section through the Permit Area which Illustrates the variable <br />• nature of the Intermediate sandstones and shales within the VenneJo <br />Formation. The Rockvale Sandstone Mertber, mentioned by Scott (b) as <br />being an unmapped marine sandstone tongue of the Trinidad sandstone and <br />located 150 feet above the base of the VermeJo Fortretion, was not <br />10 <br />