Petroleum accumulation at the Sojourner field, Haskell County, Texas, was found in a lower Pennsylvanian sand pinch out. The prospect was first recognized as anomalous on a reconnaissance geochemical survey, leased, and then detailed by reflections, on the basis of which the discovery well was located. Since the field has been completely developed, the prediscovery predictions of the geochemical and reflection surveys can be compared with the subsurface known from well data. Pertinent maps are shown together with a discussion of the local geology and field development.