The Butte Valley and Layton Well Thrusts are major structural features in two adjacent mountain ranges west of southern Death Valley. The Butte Valley Thrust in the southern Panamint Range underlies most of the range and emplaces Proterozoic rocks over strate as young as Jurassic(?) in age. The Layton Well Thrust to the southwest in the Slate Range has been interpreted to have Proterozoic rocks juxtaposed on rocks as young as Jurassic, suggesting that that the Butte Balley Thrust and the Layton Well Thrust might be correlative. New information indicates that the allochthonous rocks of the Layton Well Thrust are Mesozoic in age and are not likely part of the same allochthon as that above the Butte Valley Thrust. In addition, the Butte Valley Thrust cuts sharply downward to the north and west across lower Paleozoic strata, suggesting that the fault roots beneath the Layton Well Thrust. The Layton Well Thrust probably belongs to the East Sierran thrust system and thus would be in the upper plate of the Butte Valley Thrust. ¿ American Geophysical Union 1995.