20 A. G. LEONARD 



River formation, the lower or Titanotherium beds, the middle or 

 Oreodon beds, and the upper or Protoceras beds. 



It is probably this area, in what was then Dakota Territory, 

 which was visited by E. D. Cope in 1883, and from it he collected 

 twenty species of vertebrates, including Trionyx, Galecynus gregari- 

 ous, Aceratherium, Elotherium ramosum. Oreodon, and Leptomeryx. 



The beds of the White Butte locality have been described in 

 considerable detail by Earl Douglass,^ and in the middle member, 

 or Oreodon beds, he found the following vertebrate fossils: Ictops, 

 Ischyromys, Palaeolagus, Merycoidodon culhertsoni, Leptomeryx 

 evansi, Mesohippus, Hyracodon, Gymnoptychus, Eumys, and Acera- 

 therium. Another White River area was discovered by Douglass 

 about 30 miles northeast of White Butte, in western Stark County. 

 All three members of the White River formation are here present 

 and contain mammalian bones. 



The 40 feet of calcareous clay and compact, siliceous, thin- 

 bedded limestone occupying a few acres on top of Sentinel Butte, in 

 Golden Valley County, is referred to the White River formation. 

 Seventy miles east of White Butte, in Grant County, the White 

 River formation occurs on the tops of three high buttes. The 

 deposits are briefly described by E. R. Lloyd^ as consisting of about 

 50 feet of calcareous sandstone overlying a marly limestone, both 

 being referred to this formation "on faunal and lithologic evidence." 



Far to the north of the above-mentioned areas, in the Killdeer 

 Mountains of northwestern Dunn County, there are 400 feet of 

 strata which are so wholly unlike the underlying Fort Union, on 

 which they rest unconformably, that they have been referred to 

 the White River formation. This area has recently been described 

 by T. T. Quirke.^ The deposits here consist of green or pink non- 

 plastic clays, green friable calcareous sandstones, limestones, and 

 chalklike arenaceous marl. The rocks are similar in character to 

 those of the White River formation found elsewhere in the region, 

 and they undoubtedly belong to that formation. 



^Annals of the Carnegie Museum, V, Nos. 2 and 3 (1909), 281-88. 



2 E. R. Lloyd, "The Cannonball River Lignite Field, North Dakota," U.S. Geol. 

 Survey, Bull. No. 541, 1914, p. 251. 



3 T. T. Quirke, "The Geology of the Killdeer Mountains, North Dakota," Jour. 

 Geol, XXVI (1918), 255-71. 



