Gaudry was one of the first scientists to invent a phylogenetic tree for fossil forms in 1866.

Gaudry was an advocate of theistic evolution.
In his book Essai de paléontologie philosophique (1896) he considered evolution to be a divine plan guided by God.

Charles Darwin cited Gaudry's palaeontological research from his excavations at Pikermi in the second edition of On Origin of Species, 1872 and The Descent of Man, 1871.
His research was also positively cited by Alfred Russel Wallace.
Gaudry discovered and reconstructed several new mammal species that he considered were intermediates, he believed these were evidence for evolution but differed from Darwin in believing they were the result of a plan by God.

Because of his spiritual beliefs, he rejected the idea of natural selection and struggle for existence.
Paleontologist Éric Buffetaut has written that "Gaudry's strong religious feelings made it difficult for him to accept Darwin's mechanistic vision of an evolution based on chance and natural selection.
Evolution was acceptable to him because it revealed a unity in the organic world which was the mark of divine works."
Gaudry was one of the first scientists to invent a phylogenetic tree for fossil forms in 1866.
Gaudry was an advocate of theistic evolution. In his book Essai de paléontologie philosophique (1896) he considered evolution to be a divine plan guided by God.
Charles Darwin cited Gaudry's palaeontological research from his excavations at Pikermi in the second edition of On Origin of Species, 1872 and The Descent of Man, 1871. His research was also positively cited by Alfred Russel Wallace. Gaudry discovered and reconstructed several new mammal species that he considered were intermediates, he believed these were evidence for evolution but differed from Darwin in believing they were the result of a plan by God.
Because of his spiritual beliefs, he rejected the idea of natural selection and struggle for existence. Paleontologist Éric Buffetaut has written that "Gaudry's strong religious feelings made it difficult for him to accept Darwin's mechanistic vision of an evolution based on chance and natural selection. Evolution was acceptable to him because it revealed a unity in the organic world which was the mark of divine works."
Jean Albert Gaudry