34 



LAKAMIE FLORA OF THE DENVER BASIN. 



formation was classod as "Cretaceous or Ter- 

 tiary." 



In May, 1911, I published a short paper" 

 entitled "Further data on the stratigraphic 

 position of the Lance formation {' Cera tops 

 beds')," which gave the results of the work of 

 the two field seasons that had intervened since 

 the publication of my first paper on this sub- 

 ject. What was then thought to be the most 

 important result recorded was the finding in 

 t\irl)on County. Wyo., of the remains of Tri- 

 ceratops in the so-called "Upper Tiaramie" of 

 Veatch, above the supposed profound uncon- 

 formity as described and mapped by him. 

 After describing this occurrence I made the 

 following statement: 



since, w-ith the exception of their occurrence in the 

 post-Laramie deposits of the Denver Basin, the remains 

 of Triceratops have never been found outside the Lance 

 formation, the finding of Triceratops at this point is of 

 far-reaching importance. It shows that not only are the 

 beds containing them above more than 6,000 feet of 

 ''Laramie" rocks (the basal portion of ■which is almost 

 certainly of Fox Hills age), but also that they are separated 

 from the "Laramie" ["Lower Laramie"] by an uncon. 

 formity, which, according to Veatch, is profound and has 

 involved the removal of perhaps as much as 20,000 feet 

 of sediments. This would seem effectively to dispose of 

 the contention that the Lance formation [" Ceratops beds"] 

 is the equivalent of the Laramie. 



Another part of this paper was an important 

 contribution of several pages by W. R. Calvert, 

 on the stratigraphic relations in the old Stand- 

 ing Rock and Cheyenne Indian Reservation, in 

 South and Xorth Dakota, as observed by him 

 and by the parties under his charge. In this 

 contribution particular attention was devoted 

 to the Fox Hills and the overlying Lance 

 formation. Calvert said: "As a result of field 

 study by Pishel, Barnett, and the writer, it 

 seams certain that the line between the Fox 

 U\\h sandstone and the Lance formation is 

 marked by an luiconformity." Calvert pointed 

 out that the Fox Hills has a maximum thick- 

 ness of 200 feet in this region, but it was found 

 to vary greatly, and in some places it was 

 entirely absent, the Lance formation resting on 

 the Pierre. Angular as well as erosionnl dis- 

 cordances between the two were noted. 



Calvert was of the opinion that the reported 

 occurrence of Fo.x Hills invertebrates in the 

 lower part of the Lance 



>< Jour. Geology, vol. 19, pp. 358-376, 1911. 



may be looked at from two divergent points of view. Be 

 cause Fox Hills fossils occur in the lignitic shales at the 

 base of the "somber beds" and mingled mth the brackish- 

 water types of the Lance formation is not necessarily proof 

 positive that the various faunas lived at the same time, for 

 if the deposition of the Fox Hills was followed by a definite 

 erosion interval, what is more probable than that in the 

 deposition of succeeding strata fossil shells would be 

 eroded from the marine beds and carried into the channels, 

 there to mingle with the then living brackish-water fauna 

 of the Lance formation? 



The conclusions reached in this paper were in 

 part as follows: 



It has now been demonstrated that the Lance formation 

 is everywhere followed conformably by the acknowledged 

 Fort Union — that is to say, sedimentation from one to the 

 other was continuous and uninterrupted. 



The unconformable relations between the 

 Lance formation and underlying formations 

 having been demonstrated at so many points, 

 it could only be concluded that this 

 unconformity is undoubtedly one of importance, and this 

 would seem to dispose of the contention that the Lance, 

 Arapahoe, and Denver formations may be mere "phases 

 of Laramie." * * * This point becomes more clearly 

 than ever the logical point at which to draw the line be- 

 tween Cretaceous and Tertian,-. 



Later in 1911 I published a short note'' 

 under the caption "Where are the Laramie 

 dinosaurs?" In this note the facts regarding 

 the relations between the Laramie and liance 

 formations, as recorded in previous papers, 

 were briefly set forth, and I concluded with the 

 following paragraph : 



The vertebrate paleontologists continue to refer to the 

 "Ceratops beds" as the "Laramie," the 'Laramie Creta- 

 ceous," etc., as though nothing had been ascertained re- 

 garding their position since they were named 25 years ago. 

 If there is valid evidence to show that the Lance formation 

 {"Ceratops beds") is the equivalent to the Laramie in 

 whole or in any part, it would be welcome. If there is a 

 known locality where dir.osaurs (Ceratopsidae I occur in the 

 true Laramie, information concerning it should not longer 

 be withheld. 



The report on the work of the United States 

 Geological Survey on mineral ftieis for the 

 year 1910, published in 1912,'" contains many 

 short papers and preliminary reports relating 

 to Rocky Mountain areas, here under consider- 

 ation. In these papers, by Pishel," Calvert," 



■5 Sden?e, new ser., vol. 34, p. 320, I91I. 



i« T;. S. Geol. Survey Bull. 471, 1912. 



>' I'Lshel, .M. .\., Lignite in the Fort Berthold Indian Reservation, N. 

 Dak.: Idem, p. 170. 



"Calvert, W. R., Geology of certaui lignite fields in eastern Mon- 

 tana: Idem, p. 187. 



