VIII. A GEOLOGICAL RECONNAISSANCE IN NORTH DA- 

 KOTA, MONTANA, AND IDAHO; WITH NOTES 

 ON MESOZOIC AND CENOZOIC GEOLOGY. 



By Earl Douglass. 



In July, 1905, Dr. Percy E. Raymond and Earl Douglass were 

 sent by the Director of the Carnegie Museum, Dr. Wm. J. Holland, 

 to collect both vertebrate and invertebrate fossils in Minnesota, North 

 Dakota, Montana, and Idaho, and to obtain data for the settlement 

 of certain geological problems, which arise in the study of the various 

 extinct faunas of that region. 



Previous to starting for the field, Mr. Douglass submitted to the 

 Director an outline of the work, which it was hoped might be accom- 

 plished, provided that the discovery of large numbers of fossils of 

 unusual interest did not shorten the work of exploration. This plan, 

 which in substance is given below, was approved by Dr. Holland. 



1. It was proposed that collections of fossils be made from the 

 Ordovician rocks near St. Paul and from Straight River between Fari- 

 bault and Owatonna in Minnesota. 



2. The bad-lands of the Little Missouri River in North Dakota, 

 especially the section near Medora on the Northern Pacific Railroad, 

 had been very graphically described by geologists and other observers, 

 but the geological age of the beds of which they are composed re- 

 mained doubtful. They had been referred to the Laramie, but not, 

 so far as the author was aware, on account of the discovery in them 

 of characteristic Laramie fossils. It was hoped that data might be 

 obtained which would promote a settlement of the question. The 

 region appeared to be favorable for the discovery of vertebrate fossils. 



3. In the vicinity of Glendive, on the Yellowstone River in the 

 eastern part of Montana, are bad-lands which differ in color and gen- 

 eral aspect from those of the Little Missouri River. These, while 

 sombre and desolate in appearance as seen from car-windows, are very 

 alluring to the fossil -hunter, and the present writer had never seen 

 them on his trips to and from the west without a desire to explore 

 them. Professor Lester F. Ward had made collections of plants from 



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