FORT UNION OF CRAZY MOUNTAIN FIELD, MONT. 9 



discoveries of 1902 and 1903 on and around Cayuse Butte, and he 

 found no mammals on his brief visit. His account of this trip (Doug- 

 lass, 1909) includes a resume of the geology of the area, involving also 

 bis observations in 1900 and 1901. 



In the meantime Silberling had continued prospecting the field and 

 had located the two richest known deposits, later developed as the 

 Silberhng and Gidley Quarries. He was for a tim^e associated with the 

 Carnegie Museum, to which Douglass had now also gone, and he sent 

 in to it a small but important collection, principally from the Silberling 

 Quarry. This was described by Douglass a few years later (Douglass, 

 1908) and was the basis of the first exact definition of mammals from 

 this field, including the types of Ptilodus montanus, Picrodus silber- 

 lingi, Coriphagus montanus, and Alegopterna minuta,^ as well as many 

 less exactly identifiable specimens. 



In 1907 (see Stone, 1909) R. W. Stone worked in the northern part 

 of this area for the United States Geological Survey, and in 1908 

 W. R. Calvert worked south of the area. They connected their ob- 

 servations west of the Crazy Mountains, and in 1909 also by recon- 

 naissance east of the mountains and later published an important 

 discussion of the Fort Union here and of its relations to the Livingston, 

 applying the name Lebo to the lower part of the Fort Union (Stone 

 and Calvert, 1910). 



In 1908 Dr. T. W. Stanton visited the field, where he was accom- 

 panied by Silberling, who had in the meantime left the Carnegie 

 Museum and started ranching in this area. They made detailed 

 observations, including a section of the Lebo which I give on a later 

 page, and Silberling was employed under Stanton's direction to collect 

 for the United States Geological Survey and National Museum 

 (Stanton, 1909). Ejiowlton had taken some interest in observations 

 here, principally in connection with his placing of the Hell Creek and 

 synchronous beds in the "Lower Fort Union" (see Knovvlton, 1909), 

 a view now universally abandoned and requiring no consideration 

 here. In 1909, Stanton, Stone, Calvert, Knowlton, and M. R. 

 Campbell briefly visited the area again to check certain critical 

 locaHties, the results of their observations being principally given by 

 Stone and Calvert (1910). Stanton (1914) and Knowlton (1914) 

 later returned to their argument regarding the Cretaceous-Tertiary 

 boundary, but with only incidental reference to this area. 



Silberling continued the collecting begun in 1908 and spent much 

 time in 1909, 1910, and 1911 collecting for the National Museum. 

 It was in these years that he obtained most of the specimens described 

 in this work. A few specimens collected in later years were also 

 acquired by the National Museum, and Silberling has continually 

 spent much time in the field, even when not commissioned by any 



9 Which is, however, invalid. 



