Note: For the undergraduates embarking on learning more about geology, some of the below references are fairly technical. Do not let that dissuade you. You can still get a lot out of reading them.
Collins, S. F., & Knode, R. H., GEOLOGY AND DISCOVERY OF THE CROW BUTTE URANIUM DEPOSIT, DAWES COUNTY, NEBRASKA http://www.wma-minelife.com/uranium/papers/crwbtt01.htm. This describes the geology of a Uranium deposit within the basal Tertiary unit, just some 15 mils to the south. Figure 15 is particularly interesting. Other works relate the timing of U mineralization and the chalcedony veining seen in the area.
Diffendal, R., 2002, Joints, faults, angular unconformities: Harlan County Lake, Nebraska; GSA Abstracts w Program, v. 34, # 6, p. 79. This describes the array of normal faults seen at Harlan County.
LaGarry, H., Geology of the Montrose, Orella, Wolf Butte, Roundtop and Horn 7.5' USGS quads, UNL Ph.D. dissertation. This has a lot of detailed description of the stratigraphy, but also discusses and maps some of the major faults.
Lander, R. H. & Hay, R. L., 1993, Hydrogeologic control on zeolitic diagenesis of the White River sequence: Geol. Soc. of America Bulletin, v. 105, p. 361-376. This is a detailed interesting paper that is relevant because it discusses the diagensis that may have contributed to vein and fault minerlization.
Lester, J., 2002, Cenozoic Tectonics of the Black Hills, South Dakota: Deformation of a unique White River Group (Orellan) Lake deposit and other regional evidence; GSA Abstracts w Programs, v. 34, # 1.
Moak, W., Tegels, J., & Maher, H. D., Jr., 2004, Faults and veins in White River Group Strata of Toadstool Geologic Park, Northwest Nebraska; GSA Abstracts w Programs, vol. 36, #3, p.41. This is an abstract summarizing some of the early work done on this project.
Townend, J. & Zoback, M. D., 2000, How faulting keeps the crust strong; Geology, 28, p. 399-402. This is a conceptual piece that could help explain more distributed intraplate strain patterns.
Warner, L. A., 1978, The Colorado Lineament: A middle Precambrian wrench fault system: Geological Society of America Bulletin, v. 89, p. 161-171. This notes the existance of a NE-SW trending zone of structures that is 100 km or so wide, which the Toadstool fault could be considered a continuation of.