NA TURE 



[August 4, 1904 



AMERICAIS 



EXTINCT VERTEBRATE 



ANIMALS.' 



SINCI-2 the foundation of a department of vertebrate 

 palaeontology in the American Museum of 

 Natural History in 1891, the curator, Prof. H. F. 

 Osborn, and his assistants have made some most 

 remarkable contributions to our knowledge of the 

 extinct vertebrate animals of North America. The 

 published work of the first six years was collected in 

 one volume at the end of 1897, and the still more 

 numerous papers contained in the museum Bulletin 

 during- the last six years have just been bound together 

 in a second volume, which is now Issued for sale or 

 exchange. Since 1897, fiv* large quarto memoirs on 

 ixtlnct Reptllla and Mammalia have also appeared 

 under the same auspices. All these publications are 

 Illustrated both by photographs and by excellent 

 drawings, which not only explain the technical points 

 of the descriptive letterpress, but are also in manv 

 cases beautiful works of art. 



The pioneer explorations of Leldy, Marsh, and Cope 

 in the arid regions of the west, where the rocks are 

 nut nh-iHin d liv \-. '"-el rili "m , icXi , ilid niorr or los-, in- 



.loration of Four-t,jijil lK,i,€ ( 

 Eocuieof Wyo 



complete evidence of the evolution of several groups 

 of land mammals. Their work is now ably continued 

 bv the American Museum in the more favourable 

 circumstances which result from the spread of 

 civilisation and railroads in the remote territories where 

 the fossils occur. Instead of making hurried forays 

 with an armed escort, the explorers are now able to 

 collect at leisure and make detailed observations of 

 the rocks. Photographs are taken of all the important 

 sections and diggings, and notes are made to deter- 

 mine the exact geological position and relative age 

 of all the skeletons collected. The succession of extinct 

 animals in western North America is thus being 

 gradually determined with certainty, and rests less on 

 inference than formerly. The fossiliferous deposits 

 themselves are also better understood, and some of 

 the earlier conclusions as to their origin have been 

 considerably modified by these later researches. For 

 instance, it appears from Dr. W. D. Matthew's work 

 in connection with the American Museum that many 

 of the famous bone-beds in the west are not contained 

 in the sediments of old lakes of immense extent, but 

 are largelv wind-borne, and have accumulated on 



1 " Fossil Vertebrates in the Anr^ri 

 Department of Verteljrate Paljeontolnqy, 

 the American Museum Biillelhis of the ■ 

 Henry Fairfield Oshorn, Curator. 



.9 



M 



Vol 



1 of Natural History 

 Articles collected from 

 898-1903. With a preface by 



plains where there were Yar3'ing swamps, pools, and 

 wandering streams. 



While adopting these careful methods of collecting, 

 the American Museum has recently, with the aid of a 

 generous donation from Mr. William C. Whitney, de- 

 voted special attention to the ancestry of the horses. 

 .Since 1899 expeditions have been sent out each year 

 into the various Tertiary regions to collect fossil 

 horses, and the result is that the volume now before 

 us contains some of the most important contributions 

 to this test-case of evolution that have hitherto been 

 published. It is curious that although remains of 

 horses were dug u|) and recognised in America so long 



ago as 1826, no complete fossil .skeleton had been 

 found until Mr. J. W. Gidley quite lately discovered that 

 of the Eqiius scotti in the Lower Pleistocene of Texas. 

 His collection now in the American Museum comprises 

 satisfactory remains of many individuals, and makes 

 it possible for the first time to realise the exact nature 

 of the true horses which were once so abundant on 

 the North American continent, and strangely became 

 extinct before the dawn of history. A complete 

 .skeleton of a three-toed horse (Neohipparion wbiineyi) 

 is also described by Mr. Gidlev from the Upper Miocene 

 of South Dakota, and another nearly similar complete 

 skeleton (Fig. 2) was discovered by Mr. Barnum 

 Brown in 1901 in the Middle Miocene of Colorado. 

 These remarkable fossils are mounted in the American 



NO. 



18 14, VOL. 70] 



