320 



SCIENCE 



[N. S. Vol. XXXIV. No. 871 



tinct from the Laramie, and the contention is 

 here made that these beds, which include the 

 ' Hell Creek beds ' and so-called ' somber 

 beds ' of Montana, the ' Ceratops beds ' or 

 ' Lance Creek beds ' of Wyoming, and their 

 stratigraphic and paleontologic equivalents 

 elsewhere, are to be regarded as constituting 

 the lower member of the Fort Union forma- 

 tion and are Eocene in age." 



In that paper it was shown that the dino- 

 saur-bearing beds (" Ceratops beds ") rest, in 

 some cases unconformably, in others in. ap- 

 parent conformity, on Fox Hills or Pierre, 

 and the conclusion was reached that an 

 erosional interval is indicated during which 

 the Laramie — if ever present — and other Cre- 

 taceous and early Tertiary sediments were re- 

 moved. From this it follows that the beds 

 under consideration, being above an uncon- 

 formity, can no longer be considered as a part 

 of the " Conformable Cretaceous series," and 

 hence are not Laramie. It was also shovm 

 that these beds can not be separated on struc- 

 tural or lithologic grounds from the overly- 

 ing acknowledged " yellow "-bed Fort Union ; 

 in other words, that sedimentation was con- 

 tinuous and uninterrupted. 



The results of the work of two field seasons 

 in critical areas have just been published 

 (June, 1911),° showing that the results of the 

 first paper are confirmed in every particular. 

 For instance, on the North Platte River, 

 opposite the mouth of the Medicine Bow 

 Eiver, in Carbon County, Wyoming, remains 

 of Triceratops were found in beds (typical 

 " Ceratops beds ") alove 6,000 feet of un- 

 doubted Laramie, and from which they are 

 separated by an unconformity which, accord- 

 ing to Veatch, has involved the removal of 

 over 20,000 feet of strata. This would seem 

 forever to dispose of the contention that the 

 " Ceratops beds " are in any way the equiva- 

 lent of the Laramie. A short distance to the 

 northeast of this locality, in Converse County, 

 Wyo., the Laramie is entirely absent and the 

 dinosaur-bearing beds rest without observed 



= ' ' Further Data on the Stratigraphic Position 

 of the Lance Formation ('Ceratops Beds')," 

 Jour. Geol, Vol. 19, 1911, pp. 358-376. 



unconformity on Fox Hills. In adjacent 

 South Dakota and southeastern Montana 

 these same beds rest on Fox Hills of varying 

 thickness, often with obvious erosional un- 

 conformity, occasionally also with angular as 

 well as erosional discordance, and, in one in- 

 stance, apparently on Pierre, the whole of the 

 Fox Hills being cut out. 



In 1910 the U. S. Geological Survey for- 

 mally adopted the name Lance formation* in 

 place of " Lance Creek beds " or " Ceratops 

 beds." Wherever Lance formation is em- 

 ployed it is to be understood as including 

 " Lance Creek beds," " Ceratops beds," " HeU 

 Creek beds," " somber beds," " Lower Fort 

 Union " and dinosaur-bearing beds identified 

 as " Laramie " by many writers. 



At first the Lance formation was considered 

 to be of Cretaceous age, though obviously 

 above and distinct from the Laramie. Later, 

 however, when the facts became known as 

 above outlined, and when it became necessary 

 to place the Lance formation ofiicially" it has 

 been recorded as " Cretaceous or Tertiary." 

 This concession is regarded by the writer as 

 important, and one the value of which is not 

 to be overlooked. 



The vertebrate paleontologists" continue to 

 refer to the "Ceratops beds" as the "Lara- 

 mie," the "Laramie Cretaceous," etc., as 

 though nothing had been ascertained regard- 

 ing their position since they were named 

 twenty-five years ago ! If there is v^lid evi- 

 dence to show that the Lance formation 

 (" Ceratops beds ") is the equivalent of the 

 Laramie in whole or in any part it would be 

 welcome. If there is a knovm locality where 

 dinosaurs (Ceratopsids) occur in the true 

 Laramie, information concerning it should not 

 longer be withheld. 



F. H. Knowlton 



* See first use, Am. Jour. Sci., Vol. 30, Septem- 

 ber, 1910, p. 172. 



= Cf. Bull. U. S. Geol. Surv., No. 431 B, 1911, 

 p. 85, 



" Cf. Lull, Am. Jour. Sci., Vol. 29, 1910, pp. 1- 

 39; Brown, Bidl. Am. Mus. Nat. Hist., Vol. 28, 

 1910, pp. 267-274; Wieland, Am. Jour. Sci., Vol. 

 31, 1911, pp. 112-124. 



