Lull and Triassic Dinosaurs, 1915
Most of the dinosaurs that were discovered in the United States at the end of the nineteenth century were from the Cretaceous period (Tyrannosaurus and Triceratops) or the Jurassic period (Diplodocus and Stegosaurus). However, there was one area that yielded Triassic dinosaur remains, and that was the Connecticut River Valley.
Oddly, the fossil evidence there was mostly in the form of footprints, the very footprints that Hitchcock had seen as bird tracks, with actual fossils being rather scarce. Still, in the period since Hitchcock a few skeletons had been discovered, most notably Anchisaurus, which was restored by Marsh in 1893.
Richard Swann Lull was professor of Vertebrate Paleontology at Yale University, and Marsh's successor. In this survey article he sought to reconstruct the Connecticut Valley of Triassic times, using all known evidence, footprints and bones.
To aid in this visual exercise, he made models of Triassic dinosaurs in the round, which was, he claimed, "an old idea but newly applied in prehistoric restorations." Actually, it wasn't all that new--as we have seen, Charles Knight was already in the habit of doing three-dimensional restorations-- but Lull did add a novel twist. When he sculpted his Anchisaurus, he gave one side the appearance of skin and muscle, while he cut the other side away to reveal the internal skeleton.
Lull's study is still the classic monograph on the Connecticut Triassic, and has proved so indispensable that it was reprinted in 1953.
Anchisaurus, Triassic Dinosaur, 1893
Marsh is usually associated with the Jurassic dinosaur beds of Wyoming, but he taught at Yale University in New Haven, in the Connecticut River Valley, just south of where Hitchcock had discovered bird-like tracks in Triassic rocks a half-century earlier. Between 1889 and 1893 Marsh announced the discovery of five carnivorous dinosaurs in the Connecticut sandstone, of which the best represented was Anchisaurus. In his restoration, Marsh portrayed the dinosaur as bipedal, but he pointed out that the large fore limbs allowed for the possibility that it moved on all four feet. Marsh concluded by re-iterating that it was now evident that the supposed “bird tracks” of the Connecticut valley were made by dinosaurs like Anchisaurus.