This included evidence that birds had evolved from reptiles, including the discovery of Archaeopteryx in Europe, and a number of fossils of primitive birds with teeth found in North America.
Entre elas estaban as probas de que as aves evolucionaran dos réptiles, incluíndo o descubrimento do Archaeopteryx en Europa, e varios fósiles de aves primitivas con dentes atopados en Norteamérica.