Original: He also found early horses, flying reptiles, the Cretaceous and Jurassic dinosaurs; Apatosaurus and Allosaurus, and described the toothed birds of the Cretaceous; Ichthyornis and Hesperornis.
Simplified: He also found early horses, the Cretaceous and Jurassic dinosaurs Apatosaurus and Allosaurus, and described the toothed birds of the Cretaceous; Ichthyornis and Hesperornis.