Field and Laboratory

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Location.-The Lancaster Quadrangle is in southwestern Dallas County and northwestern Ellis County. It is bounded on the north by parallel 32 ° 37' 30"; and on the south by parallel 32 ° 30' 00"; on the west and east by meridians 96° 52' 30" and 96° 45' 00", respectively. Methods of Study.-The field work was done during the summer and fall months of 1956. A state highway map of Dallas and Ellis counties was used as the base map for this study. The geology was plotted on aerial photographs and later transferred to the base map with the aid of a vertical sketchmaster. Contacts between various stratigraphic units exposed in the area were designated on the basis of the following criteria. Difference and abundance of vegetation, though unreliable alone, was used for distinguishing different types of lithology when used in conjunction with other factors. In some cases, soil color played a minor role as the distinguishing factor. In some instances relative resistance to erosion provides a tentative criterion for correlation in the Austin Chalk. Seven stratigraphic sections were measured in detail by the author and Thomas E. Williams, along a line approximately normal to the regional strike of the beds. These sections were measured with a steel tape, and each recognizable lithic unit was sampled. Samples later were crushed and one hundred grams of each were treated with dilute HCl until all carbonates were digested. The insoluble residue was filtered and washed to remove the calcium chloride, and then dried and weighed. Accessibility.-The Lancaster Quadrangle is accessible from north and south by U.S. Highway 77 and State Highway 342, and from the east by Farm Road 1381. The quadrangle is also transected by a series of hard-surfaced, gravel and dirt roads; but only that part of the quadrangle in Dallas County has all-weather roads.

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This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

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