From the Cretaceous of Kansas he has obtained the first American Pterodactyles, including a new order (Pteranodontia), a new sub-class of birds with teeth (Odontornithes), including two new orders, the Odontolcæ and Odontotormæ and many new Mosasauroid reptiles. In the anatomy of the latter group he has made a number of interesting discoveries which have been of great value in determining its relationship. From the Eocene Tertiary of the Rocky Mountains, he has brought to light the first monkeys, bats, and marsupials, found in this country; two new orders of mammals, the Tillodontia, which seem to be related to the Carnivores, Ungulates, and Rodents; and the Dinocerata, which were huge Ungulates, elephantine in bulk, bearing on their skulls two or more pairs of horn cores. From the same Eocene come the two earliest equines, Eohippus and Orohippus, and a host of other strange forms, all of them widely different from anything now living.
In the Miocene lake-basins of the West, Prof. Marsh has found numerous other forms, many of them apparently descendants of their predecessors in the Eocene, while others seem to stand alone. In the Miocene of the Plains occur the huge Brontotheridæ, a new family of Ungulates, first defined by Prof. Marsh. In size they equaled the Dinocerata of the Eocene, and like them their skulls were armed with horns. The same formation has also yielded to this explorer the first Miocene monkey found in America, while from the Oregon lake of this age he has described the oldest known Edentates. The new fossils obtained from the Pliocene lake-basins of the Plains and of Oregon are not less numerous than those from the earlier ones, but they are of less interest to the general reader. The remains of these ancient creatures, preserved in the Museum of Yale College, present a series which, for its interest and value to the biologist, is not surpassed by any collection in the world. Not less than four hundred new species of fossil animals have been collected by Prof. Marsh, and their remains are all at present in New Haven.
Prof. Marsh is President of the American Association for the Advancement of Science, and will preside at the St. Louis meeting this year; and, as retiring president, will deliver his address in 1879. At the meeting of the National Academy of Sciences in Washington, in April last, he was elected vice-president of that body, and, by the death of Prof. Henry, he has become its presiding officer. He is a member of several scientific societies in Europe, and has recently received from the Geological Society of London the Bigsby medal for his important discoveries in paleontology.
Prof. Marsh is a nephew of the late George Peabody, Esq., of London, and the most important gifts to science by this philanthropist are due to his influence. The Peabody Museum of Natural History, at New Haven, the Peabody Museum of Archæology and Ethnology, at Cambridge, as well as the Peabody Academy of Science, in Salem, Massachusetts, are largely the results of his advice and carefully-considered