348 T. W. STANTOX CRETACEOUS-TERTIARY BOUNDARY 



and that the erosion interval may have been long in the Denver basin, 

 there are still other questions to be considered before deciding that the 

 break marks the boundary between Cretaceous and Tertiaiy. How great 

 an area was affected by the movement? Can the break be identified with 

 the one which separates marine Cretaceous from marine Tertiar}' in 

 other areas? What is the testimony of paleoutolog}- in all its branches 

 concerning the relationships of the faunas and flora.? in the formations 

 immediately above the unconformity? . 



The answers to these questions are not all harmonious, but some prog- 

 ress has been made toward ascertainino: the facts, and this conference 

 ought to mark another step in advance. The presence of andesitic ma- 

 terial in sediments can not now be accepted an evidence that "the great 

 unconformity" is beneath it, nor can tlie occurrence of ceratopsian diHO- 

 saurs be taken as proof of general diastrnphism just before they came on 

 the scene. The unconformity beneath the Livingston has disappeared. 

 The unconformit}' described by ^'eatch in southern Wyoming between 

 "Lower Laramie" and "Upper Laramie" must await more detailed areal 

 and stratigraphic studies before it can be properly evaluated. It will 

 suffice for the present to state that in the only area where his 'HTpper 

 Laramie" which has yielded Triceratops or dinosaurs of any kind, the 

 "Lower Laramie" also contains ceratopsian remains, and that the tvvo 

 geologists (Beekly and Bowen) who have recently examined the area in 

 detail liave failed to find there any conclusive evidence of unconformity 

 Ijetween the Triceratops-bearing beds and the "Lower Laramie." The 

 post-Vermejo unconformity of northern Xew ^fexico has been correlated 

 by Lee and Knowlton with the post-Laramie unconformity of the Denver 

 basin on the evidence of fossil plants in the overlying Raton formation, 

 and this correlation may be correct. Xo other classes of fossils have been 

 found here to serve as a check on the plants. 



The Laxci: Formatiox 



djstribvtiox axd gexeral character 



It will be remembered that in ea,stern Wyoming, South Dakota, Xortli 

 Dakota, and some other areas north of the Denver basin it has not been 

 possible to agree on the prop«M- n-jo of the term Laramie, and therefore 

 the non-committal name Lanrr formation lias been adopted for the non- 

 marine dinosaur-bearing formation, formerly called "Ceratops beds" and 

 various other names, overlying the Fox Hills sandstone where that for- 

 mation as such is present. The Lance formation has a vertebrate fauna 

 which IP closely = related to- the fauna of the Denver formation and less 



