152 Odden — Castile Gypsum and Rustler Formation. 



indicate that the Castile Gypsum is not Permian, and show 

 that the Castile Gypsum is not a stratigraphic unit, but contains 

 considerable amounts of marly clay in separate beds. 



In the latter half of 1914 the Troxel Oil Company made a 

 test hole for oil near the center of the south line of Survey 24, 

 Block 110, on the Public School Lands in Culberson County. 

 This (is about one mile east of Rustler Springs. Mr. C. Pt. 

 Troxell has furnished the writer a set of cuttings from this 

 exploration. A description of these cuttings is as follows : 



Description of Samples of Cuttings from Troxel Well No. 1, located near the 



south line of Survey No. 24, Block 110, Public School Lands, 



Culberson County, Texas. 



Depth in feet 

 below surface. 

 From To 



White gypsum. Slight effervescence with acid 4 8 



Dolomite, gray and yellow, of a fine, uniformly 

 sized crystalline texture. In thin section it 

 shows scattered porosities and minute yellow 

 streaks or blotches believed to be bituminous. 

 The sample contains some black, some gray, 

 and some white quartz. Pyrite and gypsum 

 are present 42 58 



Mostly yellow and in part dolomitic limestone. In 

 thin section this is seen to contain fine sand 

 and some other clear, transparent particles. 

 Some is porous and contains black specks of 

 pyrite. Pyrite and gypsum, some fibrous, are 

 present. Some fragments of red and yellow 

 sandy gypsum noted 74 90 



Gypsum, mostly coarse-grained, at 105 



Red shale, with some gypsum, fragments of lime- 

 stone and some dark quartz pebbles 115 123 



Gray marly material, with many fragments of dark 

 dolomite, some fine sandstone having a calca- 

 reous cement, a yellow sandy limestone, g} r p- 

 sum, pyrite and quartz sand. The dark dolo- 

 mite contains transparent angular quartz grains 

 and some scattered needle-like crystals, also 

 traces of fossils, and has faint reddish bitumi- 

 nous (?) streaky blotches. The crystals in the 

 dolomite are from 0'005 to 0-01 mm. in diame- 

 ter. Among the finer fragments of the sample 

 were found several foraminifera which are unlike 

 Paleozoic forms, and resemble Textularia glob- 

 idosa Ehrenberg, Globigerina bulloides d'Or- 

 bignjr, Bulimina pupoides d'Orbigny, Anoma- 

 lina ammonoides Reuss, Nodosaria sp 141 145 



