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aquiclude throughout most of the formation thickness and is the confining unit over the Fountain <br />Formation. The impermeable siltstone and claystone beds in the Morrison Formation form a tight <br />stratigraphic trap in which oil and gas shows are contained, and small quantities of poor quality <br />(saline) water. Both of these units form an aquiclude overlying the Fountain Formation. The <br />Fountain Formation itself contains beds of siltstone, conglomerate and micaceous shale (Howard, <br />1966, Gerhard, 1967) and is characterized by rapid lateral and vertical facies changes having <br />wide ranges of values of hydraulic conductivity. These units are low permeability facies within <br />the Fountain Formation that overlie beds of homogeneous sandstone that are saturated, forming <br />the producing zone at intervals 2675-2738 ft. and 2778-2797 ft. depth. <br />According to the driller's log of the Mutual Oil Development Co. Well (Park Center Well), small <br />quantities of poor quality water occur in thin permeable beds in the lower Morrison Formation at <br />about 500 ft. depth, and in the Fountain Formation at about 1250 ft. An oil show was found in <br />the Morrison at 245 ft. depth; oil and gas shows were found at several de.-p intervals in the <br />Fountain Formation down to about 2,000 feet depth. A high rate of water flow under artesian <br />pressure was found in the lower Fountain Formation at about 2680 feet depth. The potentiometric <br />surface (as indicated by the shut-in pressure) of the water in the Fountain Formation was at 358 <br />feet ahove land surface when the well was drilled. The artesian pressure has not declined <br />appreciably since the well was drilled in 1925. <br />(;round Water Flow S s~ tem <br />Ground water in the area of the Park Center Well occurs in two flow systems, a shallow system <br />and a deep system. The shallow flow system includes an unconfined aquifer in alluvial deposits <br />along Fourmile Creek, thin permeable beds within the uppermost part of the Morrison Formation <br />at depths of perhaps as much as 200 ft., and possibly some areas of the uppermost beds of the <br />Fountain Formation. The deep flow system consists of confined aquifers and includes a few thin <br />permeable beds in the lower part of the Morrison Formation and a relatively thick section of <br />sandstonelconglomerate in the lower part of the Fountain Formation. This is the zone in which <br />the Park Center well obtains its water; it is separate and isolated from the shallow flow system. <br />The confined aquifer system in the Fountain Formation receives its recharge from outcrops to the <br />north and on tilted beds along the east and west sides of the Chandler Syncline. <br />In the shallow flow system, the alluvial deposits along Fourmile Creek are locally saturated and <br />are in direct hydraulic connection with streamflow in Fourmile Creek. Streamflow in Fourmile <br />Creek may provide some limited recharge to shallow parts of the underlying Fountain Formation, <br />but this mechanism is not established and there are no streamflow measurements available from <br />which accurate quantification can be made of streamflow losses to the aquifer or gains in <br />streamflow from aquifer discharge to the stream. Because of the presence of low permeability <br />beds throughout most of the Fountain Formation, the amount of recharge to the deep aquifer <br />from streamflow would likely be small, if any exists at all. <br />Aquifers in the upper Morrison Formation are recharged by precipitation directly on the <br />Morrison Formation or on overlying strata such as Quaternary I andslide deposits as mapped by <br />4 <br />