Having completed our Diplodocus scapulocoracoid, during Dino Day last Saturday we opened a new dinosaur jacket. This appears to be a somewhat crushed sauropod right femur (thigh bone). You’re looking at the posterior surface, with the proximal end at the left and the distal (knee) end at the right (the distal end is poorly preserved). The bulge near the middle is the fourth trochanter, a muscle attachment point. The large light-colored patches at each end are gypsum deposits, which need to be removed. Compare the shape to this Apatosaurus mount from the Sam Noble Oklahoma Museum of Natural History:
I’ll have more updates as the preparation progresses.