30 



LARAMIE FLORA OF THE DENVER BASIN. 



One of the first of these so-called coal reports 

 \yas made by A. 0. Veatch ^ for a large area in 

 southwestern Wyoming, though the coal report 

 was expanded into a complete consideration 

 of the geologj' and resources of the region 

 co\ered. (See p. 67.) In 1906 this work was 

 systematized and prosecuted in all the Rocky 

 Mountain States, though the results were not 

 published until 1907. 



In the present connection the report by 

 A. G. Leonard " on the coal fields of ports of 

 Dawson, Rosebud, and Custer counties, Mont., 

 is of interest. This was really hardly more 

 than a reconnaissance report on a large area 

 lying mainly between Missouri and Yellow- 

 stone rivers and extending from Hell Creek 

 eastward to the State line. Four geologic 

 formations were recognized in this field — 

 Pierre, Fox Hills, "dinosaur-bearing beds" 

 not otherwise named, and Fort Union. In 

 some places, as at Glendive, the Fox Hills 

 was supposed to be absent and the overlying 

 dinosaur-bearing beds rested directly on tb.e 

 Pierre. The dinosaur-bearing beds were de- 

 scribed by Leonard as folk)Ws: 



Heretofore all the beds above the marine Pierre shale 

 have been regarded as belonging to a single formation 

 which carries the lignite and subbituminous coal beds of 

 this field. These rocks have been called at various times 

 '•Laramie" and "Fort Union," on the supposition that 

 they compose, but a single formation. The work of the 

 last year, however, has shown that at Glendive the rocks 

 above the Pierre shale app.irentl)' comprise two forma- 

 tions. * * * The beds are strikingly similar to the 

 dinosaur- bearing beds [ = "'Hell Creek beds" of Brown] 

 on Hell Creek, and presumably they are identical. 



The Fort Union was everywhere conform- 

 ably above the ''dinosaur-bearing beds" and 

 was described as " readily distinguished by the 

 light-gray and buff color of its beds." 



The economic coal investigations, which have 

 a more or less direct bearing on the present 

 problem, were continued in 1907, and the re- 

 sults were published in 1909.' A. G. Leonard 

 and Carl D. Smith reported on the Sentinel 

 Butte lignite field, in Nortli Dakota and Mon- 

 tana, where they found only the Fort Union 

 formation. Arthur J. Collier and Carl D. 

 Smith reported on the Miles City coal field, in 

 Montana, where also only the Fort Union was 

 recognized, though the lower 500 feet of beds 



* Geography and geology of a portion of southwestern Wyoming, with 

 special reference to coal and oil: U. S. Gool. Survey Prof. Paper 56, 1907. 

 » U. S. Geol. Survey Bull. 316, p. 194, 1907. 

 ' U. S. Geol. Survey Bull. 341, 1909. 



[the equivalent of the "dinosaur-bearing beds" 

 of the Glendive section] was described as show- 

 ing a marked lithologic difference. In the main 

 only the Fort Union was described by L. H. 

 Woolsey in his account of the Bull Mountain 

 coal field, in Montana, though he mentioned 

 briefly certain beds on Dean Creek and an olive- 

 green shale which he regarded as being beneath 

 the Fort Union. In the report on coal near 

 the Crazy Mountains, Mont., R. W. Stone rec- 

 ognized the marine Cretaceous section as de- 

 fined by Stanton and Hatcher for the Judith 

 River area (see p. 77), and above this, in as- 

 cending order, the Laramie, Livingston, and 

 Fort Union formations. In his report on the 

 Red Lodge coal field, Mont., E. G. Woodruff 

 referred the whole visible section of S.OOO 

 feet to the Fort L'nion, as did J. A. Taff the 

 coal-bearing section in the Sheridan coal field, 

 Wyo. On the southwest side of the Big 

 Horn Basin of Wyoming Woodruff identified as 

 Laramie ( ?) a series of sandstones and shales 

 overlying the Montana group. This series was 

 said to contain invertebrates belonging to a 

 fauna characteristic of the " Ceratops beds." 

 Woodruff said : 



As the stratigraphic position of these beds ["Ceratops 

 beds"] is not definitely determined, the name Laramie is 

 applied because the Laramie formation occupies a position 

 in the geologic column between the Montana and Fort 

 Union. * * * The name, however, should not be con- 

 sidered as indicative of a positive correlation with beds 

 of Laramie age to the south. 



The Laramie was also tentatively recognized 

 by C. W. Washburne on the northeast side of 

 the Big Horn Basin, though the evidence aside 

 from position was not very clearly stated. 



Up to 1909 there had been no formal, pub- 

 lished protest against the reference of the 

 ''Ceratops beds" to the Cretaceous, although 

 several writers had indicated that in certain 

 areas the stratigraphic relations of the dinosaur- 

 bearing beds were such that they were at vari- 

 ance with the original definition of the Laramie. 

 In this year I published a paper ' under the 

 title "The stratigraphic relations and paleon- 

 tology of the 'Hell Creek beds.' 'Ceratops beds,' 

 and ecjuivalents, and their reference to the 

 Fort Union formation," in which the following 

 was given as the thesis: 



The present paper deals with the extensive series of 

 fresh-water deposits of the Northwest, comprising what is 



' Knowlton, F. H., Washington Acad. Sci. Proc., vol. 2, pp. 179-23S. 

 1909. 



