26. First U.S. Dinosaur Mount, 1902
Charles Beecher in 1901 completed the first skeletal restoration of a dinosaur to be mounted in the United States. The specimen, called at the time Claosaurus annectens, was one of two nearly complete skeletons that had been found in 1891 by John Bell Hatcher. O. C. Marsh had published a restoration in 1892, but he had not reconstructed the specimen, so after Marsh's death, Beecher took on the project of mounting the skeleton. The restoration was the first large panel mount ever attempted. It took advantage of the fact that the bones of this specimen retained their natural position with respect to each other.
It will be noticed that the dinosaur is in a running position, with the tail off the ground. At the time, this was unprecedented for ornithopod restorations, which always had the tail dragging on the ground, as seen, for example, in Dollo's restoration of Iguanodon.
Beecher had a very practical justification for such a profound transformation; he explained that the left femur was shattered and could not be removed from the matrix, and since it was in a running position, the rest of the skeleton was mounted to conform to it.
The second illustration shows a detail of the pelvis and hind limbs as they appear on the slab after restoration. But if the pose was chosen for pragmatic reasons, Beecher did defend the high tail; he pointed out that Iguanodon trackways had never revealed the presence of tail dragging, so it seemed reasonable to suppose that the tails cleared the ground.
The name Claosaurus was one of many names this specimen has worn over the years. For a more complete story, see What's In a Name.
Source
Beecher, Charles E. "The reconstruction of a Cretaceous dinosaur, Claosaurus annectens Marsh," in: Transactions of the Connecticut Academy of Arts and Sciences, vol. 11 (1901-1902), pp. 311-324. This work was on display in the original exhibition as item 26.