TY - RPRT TI - Structure at the Upper Cretaceous Clay Spur bentonite bed, Powder River basin, Wyoming and Montana AU - J. E. Fox AU - Debra K. Higley PY - 1987 DO - 10.3133/ofr87340x UR - https://pubs.usgs.gov/publication/ofr87340X ID - ofr87340X ER -