SOUTH DAKOTA SCHOOL OF MINES 25 



Sciences of Philadelphia his monumental work "The Extinct 

 Mammalian Fauna of Dakota and Nebraska.'' In this large 

 volume he brought together the accumulated information of 

 more than twenty years and in consummate manner estab- 

 lished the White Eiver badlands as one of the great fossil 

 vertebrate repositories of the world. 



A new epoch in the investigation followed. New men 

 entered the field and institutions not hitherto represented 

 began to send out exploratory and collecting expeditions. 

 Among the institutions were Yale University, University of 

 Princeton, United States Geological Survey, American 

 Museum of Natural History, University of Nebraska, Uni- 

 versity of South Dakota, Carnegie Museum, Amherst Col- 

 lege, Field Columbian Museum and the South Dakota State 

 School of Mines. 



The first Yale party, under direction of Professor O. C. 

 Marsh ( Plate 8 ) visited the region in 1870. Professor Marsh, 

 not satisfied with the crude methods of collecting with which 

 the earliest investigators had to content themselves, under- 

 took extensive quarrying for the fossils, and developed also 

 more refined methods of utilizing detached and broken 

 pieces. In this way a number of well-preserved, complete, 

 or nearly complete, skeletons were obtained where before the 

 material was weathered and fragmentary. Complete re- 

 storations of skeletons disclose structural features much 

 more readily than detached bones and imperfect fragments, 

 and Prof. Marsh first extensively developed this feature for 

 the fossil vertebrates of the White River and other western 

 badlands. He was thus able to emphasize more easily the 

 nature of these animals and to point out more clearly their 

 profoundly significant relation to present-day life. Prof. 

 Marsh continued field work for many years, the collecting 

 being done sometimes by expeditions directly from Yale, 

 some times by collectors hired for the purpose. Following 

 the first Yale expedition of 1870, other Yale expeditions were 

 in the region in 1871, '73, '74 and hired collectors in 1886, 

 '87, '88, '89, '90, '94, '95, '97, '98. The institution was repre- 

 sented in northwestern Nebraska also in 1908. 



In this connection it may be stated that during the 

 years 1886-'90, much of the field work directed by Professor 

 Marsh was done under the auspices of the United States 

 Geological Survey, the materials collected being later trans- 



