PREFATORY NOTE 



DR. LEIDY was one of the earliest writers on paljeontological subjects 

 in the United States, and for forty years his contributions to vertebrate 

 palaeontology were both numerous and important. At the time of his death, in 

 1 891, he was engaged in the preparation of a memoir describing the vertebrate 

 fossils collected, for the most part, near Archer, Florida, by Mr. J. B. Hatcher 

 and Dr. J. C. Neal, and this paper was placed in mj^ hands for completion by 

 Major J. W. Powell, Director of the U. S. Geological Survey. The work was 

 unfortunately greatly delayed by various causes, especially by work in con- 

 nection with the World's Columbian Exposition, and has only recently been 

 finished. The memoir was offered to the Wagner Free Institute of Science 

 for publication, not only because Dr. Leidy had been president of the faculty 

 of that institution, but for the reason that its transactions had been very largely 

 devoted to papers relating to the paljeontology of Florida, Dr. Leidy having 

 written one of the volumes. An examination of the manuscript showed that 

 although Dr. Leidy had finished the study of the specimens, he had by no 

 means completed their description ; while it seemed probable, as pointed out 

 by Professor Cope,* that some of the species named by Dr. Leidy had already 

 been described under other names from the Western States. This suspicion 

 was verified by careful comparison of the Florida fossils with the types of the 

 species to which it was surmised they belonged, and while it is to be regretted 

 that it should have been necessary to treat some of Dr. Leidy's names as 

 .synonymes, it is hoped that this may throw some additional light on the rela- 

 tions between the Loup Fork formation of the West and the Alachua clays of 

 Florida. 



The changes in nomenclature, for which the present writer assumes all 

 responsibility, and the conclusions in regard to species may be briefly summed 

 up as follows : 



Rhinoceros preterits Leidy is Aphelops fossigcr (Cope) and Rhinoceros 

 longipcs Leidy is Aphelops malacorliintis (Cope). 



*Bull. U. S. Geol. Survey, No. 84. Correlation Papers — Neocene, p. 130. 



