410 FLORA OF Tin: LARAMIE GROUP. 



idea tliat it could be Jurassic had now been wholly given up by the 

 authors, who had come to regard it as the lower- part of the Fort Union 

 group. This note is as follows: "At the time we published these facts, 

 we were led by the discovery here of fresh-water shells in such a posi- 

 tion to think that some estuary dei)osits of doubtful age near the 

 mouth of the Judith lliver on the Missouri, from which Dr. Leidy had 

 described some saurian remains resembling Wealdeu types, might be 

 older than Tertiary. Later examinations, however, have demonstrated 

 that the Judith beds contain an entirely different group of fossils from 

 those found in the rock under consideration, and that they are really 

 of Tertiary age, and hold a position at the base of the Great Lignite 

 series of the Northwest." 



In discussing this same section in the First Annual Eeport of the Geo- 

 logical Survey of the Territories, 1867, Dr. Haydeu distinctly classes 

 the Judith River basin with the Fort Union group, and says : " This 

 basin is one of much interest, as it marks the dawn of the Tertiary pe- 

 riod in the West by means of the transition from brackish to strictly 

 fresh-water types. It is also remarkable for containing the remains of 

 some curious reptiles and animals, reminding the paleontologist of those 

 of the Wealden of England." 



By this time the more southern extension of the coal-bearing beds 

 had begun to receive the attention of geologists, and they had been 

 traced into Wyoming and Colorado and as far south as Eaton Pass 

 in New Mexico. Fossil plants had been found at nearly all points, and 

 their testimony was considered the most unanswerable for the Tertiary 

 age of the entire group. Indeed, down to ]S(J8, with the single excep- 

 tion of the alleged Wealden facies of the Judith vertebrates, there was 

 substantial harmony upon this point. The array of names of those 

 who had C(»nimitted themselves to tliis view after thorough study of 

 the diti'erent kiuds of fossils is truly formidable, and there can be no 

 wonder that when their position was at length challenged and the Cre- 

 taceous age of this great series asserted the conflict of opinion resulting 

 was sharp and the resistance stubborn. Messrs. Meek, Hayden, Les- 

 quereux, and, as Dr. Hayden states,' Leidy, all conceded this. Capt. E. 

 L. Berthoud had studied the formation in Colorado and inclined to take 

 the same view.- He says: "Everything that I have so far seen jjoints 

 out that the coal is either Cretaceous or Tertiary, but I believe it to be 

 Tertiary, or of the same age as the coal near Cologne, on the Rhine." 

 In an article contributed by Dr. Hayden to the American Journal of 

 Science for March, 1868 (Vol. XLV, p. 198), he reiterates his views in a 

 form that indicates that thus far they had met with no serious opposition. 



The first dissenting voice to this general current of belief seems to 

 have been raised by Dr. John L. LeConte, who had investigated the 



' Annual Report United States Geological and Geographical Survey of the Terri- 

 tories, 1874, p. ai. 

 ■^First Annual Kei)ort United States Geological and Geographical Survey, 1807, p. 57. 



