350 T. ^V. STANTON CRETACEOUS-TERTIARY BOUNDARY 



scribed^« by W. E. Calvert, A. L. Beekly, M. A. Pishel, and V. H. Bar- 

 nett, and other separate parts of the area are treated by E. Kussell Lloyd, 

 D. E. Winchester, E. M. Parks, and C. J. Hares. The marine member 

 of the Lance formation and its stratigraphic relations will be especially 

 described and discussed in the current volume of the Journal of Geology 

 in a paper by Messrs. Lloyd and Hares, who first discovered it and liave 

 collected most of the data concerning it. This marine member has such 

 an important bearing on the topic of the present discussion — the bound- 

 ary between Cretaceous and Eocene — that it must be briefly considered, 

 and in order to explain that bearing it is necessary to review some facts 

 in the history of investigation and discussion of the geology of the area 

 during the past four years. 



Lower memher and its relations with the Fox Hills. — The map- 

 ping of the Indian resen^ations by Calvert and his assistants and of 

 the Bismarck quadrangle by Leonard" developed the fact that the 

 Fox Hills sandstone, with its marine Cretaceous fauna, is exposed 

 for many miles along the Missouri TJiver, extending as far north as old 

 Fort Rice, about 20 miles below Mandan, and that it is also exposed for 

 considerable distances up the Cannonball, Grand, and Moreau rivers. 

 Throughout this area the Fox Hills sandstone is immediately overlain by 

 non-marine deposits, which in many localities weather into bad-lands 

 forms and have been referred to the Lance formation on the evidence of 

 the vertebrate fauna. Dinosaur bones are widely distributed through the 

 beds, and at a few places, as, for example, in section 12, towaiship 20 

 south, range 22 east, near Grand River, nearly south of Mcintosh, South 

 Dakota, the bones are abundant and well enough preserved to be identi- 

 fied as Triceratops, Trachodon, etcetera, clearly belonging to the Lance 

 fauna. At this place the dinosaurs are less than 50 feet above the base 

 of the formation. A considerable flora has been listed by Knowlton^- 

 from 10 localities in these same deposits, ranging in stratigraphic posi- 

 tion from 4 feet to 300 feet above the base of the formation. Knowlton 

 says of it : "The plant collections obtained from the Lance formation by 

 Mr. Calvert and the members of the several parties under his charge 

 show conclusively that the relation of this flora is unmistakably with the 

 Fort Union. In fact, with the information at hand regarding distribut- 

 tion, it is practically impossible without stratigraphic data to distinguish 



"Geology of the Standing Rock and Cheyenne River Indian Reservations. North and 

 South Dakota. Bull. 575, U. S. Geol. Survey. 



"A. G. Leonard: Bismarck folio (No. 181). Geol. Atlas V. S. V. S. Geol. Survey, 

 1912. 



"Further data on the stratigraphic position of the Lauco formation C'Ceratops 

 Beds"). Journal of Geology, vol. 19. 1911, pp. 358-376. 



