HISTORICAL REVIEW OF THE LARAMIE PROBLEM. 



77 



that were formerly referred to the Laramie 

 apparently apply with equal force to the simi- 

 lar beds in adjacent Mexico. That is to say, 

 there is every reason to believe that the Eocene 

 beds immediately above the Cretaceous line, 

 which on the Texas side of the Rio Grande are 

 referred to the Midway, continue without much 

 if any change to the Lampazos region, in the 

 the State of Nuevo Leon. Similarly, the beds 

 in the coal-bearing area of northern Coahuila, 

 south of Eagle Pass, are presumably the same 

 as or similar to the coal-bearing series in the 

 Eagle Pass region along the Rio Grande. Ac- 

 cording to my knowledge and belief the Lara- 

 mie is not present in Mexico, or if there its 

 presence must be demonstrated according to 

 modern standards established for the recogni- 

 tion of this formation. 



JUDITH RIVER FORMATION. 



The Judith River beds, in the vicinity of the 

 mouth of Judith River, Mont., have been the 

 subject of prolonged discussion and difference 

 of opinion, and even at the present time there 

 are some geologists who do not consider the 

 question of age conclusively settled. As this 

 question comes only incidentally into the pres- 

 ent discission, it is not necessary to go freely 

 into the early history of opinion, especially as 

 this has been so thoroughly covered up to 1905 

 by Stanton and Hatcher. 76 



At first Leidy's studies of the vertebrates in- 

 clined him to refer these beds to the Jurassic 

 (Wealden). The invertebrates then known 

 (1856) proved very puzzling. At one time they 

 were considered by Meek and Hayden as possi- 

 bly lowest Cretaceous, though they were de- 

 scribed as Tertiary, and ultimately Meek con- 

 sidered it highly probable that they are Cre- 

 taceous. Marine beds immediately below the 

 Judith River beds were identified as Fox Hills, 

 and the beds immediately above as Fort 

 Union. Cope, in 1875, from his extensive 

 studies of the vertebrates, referred the beds to 

 the uppermost Cretaceous but stated that the 

 fauna has "some Tertiary affinities." By the 

 time the Laramie was established by King, it 

 had come to be generally accepted that the 

 Judith River beds were stratigraphically and 



? 5 Stanton, T. W., and Hatcher, J. B., Geology and paleontology of 

 the Judith River beds: U. S. Geol. Survey Bull. 257, 1905. 



85344—22 6 



paleontologically in the proper position de-. 

 manded by the definition of the Laramie, and 

 hence we find C. A. White 7e referring to them 

 as one of the subordinate groups or regional 

 divisions of this group, as it was then called. 

 He said (p. 865): 



The proof of the identity of these widely separated 

 portions of the Laramie group consists in the recognition 

 of various species of fossil mollusks in all of them that 

 are found in some one or more of the others, thus con- 

 necting the whole by faunal continuity. 



So far as the Judith River is concerned the. 

 above disposition was consistently held by 

 White in all his subsequent publications, and 

 the subject continued practically without essen- 

 tial change until 1905, when Stanton and 

 Hatcher published the paper above mentioned. 

 As the result of their studies in the original 

 Judith River area, as well as in adjacent areas 

 in northern Montana and along Milk River in 

 Canada", they reached the conclusion that the 

 Judith River formation is of Montana age and > 

 the equivalent of the Belly River beds of 

 Canada. Their stratigraphic results and cor- 

 relations are displayed graphically in the fol- 

 lowing section : 



The Fox Hills and Laramie formations were 

 not definitely identified by them in Montana. 



The above interpretation regarding the 

 Judith River was brought in question by A. C. 

 Peale " in a long article published in 1912, in 

 which he contended that there are two forma- 

 tions lithologically similar that have been con- 

 fused, one being in the position of the Belly 

 River and preferably to be called by that name, 

 and the other — the real Judith River — being 

 later than Fox Hills and probably to be re- 

 's TJ. S. Geol. and Geog. Survey Terr; Bull., vol. 4, p. 721, 1878. 

 " On the stratigraphic position and age of the Judith River formation : 

 Jour. Geology, vol. 20, pp. 530-549, 640-652, 738-757, 1912. 



