A seismic reflection profile obtained by the Consortium for Continental Reflection Profiling [COCORP> has delineated the Wind River thrust fault which underlies the Wind River Mountains, Wyomig. This thrust fault dips at an average angle of 30¿--40¿ to a depth of 24 km and possibly to 36 km. In this paper we associate the approximately constant angle of dip with the Anderson theory of faulting. With an average dip angle of 35¿ the derived coefficient of fraction is 0.36. We consider that the Anderson theory of faulting predicts the angle of dip of activated fractures in a rock mass pervaded by fractures in random directions.