Up to 1868 Leidy alone was engaged in research in the West, but that year saw the simultaneous entrance of Marsh and Cope into this new field of research, and their exploration and descriptions of similar regions and forms soon led to a rivalry which in turn developed into a most unfortunate series of controversies, mainly over the subject of priority. This resulted in a permanent rupture of friendship and the division of American workers into two opposing camps to the detriment of the progress of our science. This breach has now been happily healed, and for a number of years the degree of mutual good will and aid on the part of our workers has been of the highest sort. The extent of the western fossil area, and particularly the explorations of three of Cope’s aids, Wortman in the Big Horn and Wasatch basins, Baldwin in the Puerco of New Mexico, and Cummins in the Permian of Texas, gave him so fruitful a field of endeavor that the occasion for jealous rivalry was largely removed. The most manifest result of Cope’s western work was the publication in 1883 of his Vertebrata of the Tertiary Formations of the West, which formed volume =3= of the quarto publications of the Hayden Survey. This huge book contains more than 1000 pages and 80 plates and has been facetiously called “Cope’s Bible.” Cope’s philosophical contributions, which covered the domains of evolution, psychology, ethics, and metaphysics, began in 1868 with his paper on The Origin of Genera. In evolution he was a follower of Lamarck, and as such, with Hyatt, Ryder, and Packard, was one of the founders of the so-called Neo-Lamarckian School in America. Cope’s principal contribution, set forth in his Factors of Organic Evolution, is the idea of kinetogenesis or mechanical genesis, the principle that all structures are the direct outcome of the stresses and strains to which the organism is subjected. Weismann’s forcible attack on the transmission theory did not shake Cope’s faith in these doctrines, for he claimed that the paleontological evidence for the inheritance of such characters as are apparently the result of _individual_ modification was too strong to be refuted. Cope was more like Lamarck than any other naturalist in his mental make-up as well as his ideas. He was also, like Haeckel, given to working out the phylogeny of whatever type lay before him, and in many instances arrived marvellously near the truth as we now see it. Associated for a while with A. S. Packard, Cope soon became chief editor and proprietor of the American Naturalist, which was for many years his main means of publication and thus served our science in a way comparable to the Journal. As Osborn says by way of summation: