342 T. W. STANTON CRETACEOUS-TERTIARY BOUNDARY 



surface. There is evidently here a considerable gap in the geological 

 record." Remembering that there is also a very remarkable faunal break 

 here, it is evident from this description tliat the boundary between Cre- 

 taceous and Tertiary as originally established complied with all the de- 

 mands of the most advanced modern school of stratigraphy in which 

 diastrophism theoretically holds the highest place. The old-time paleon- 

 tologists were also equally well pleased with the boundary because the 

 marine invertebrate faunas on either side of it are in very sharp contrast. 

 Not only is there an abrupt change in the species, but many genera, 

 families, and even orders which flourished in the Cretaceous do not pass 

 beyond its upper limits, while many new types are introduced in the suc- 

 ceeding Eocene. 



Where such conditions exist, as they do in many parts of Europe, there 

 is no difficulty in fixing the limits between Cretaceous and Tertiary ; but 

 in Denmark, in Belgium, in the middle of the Paris basin, and in some 

 other parts of Europe there are deposits, in part marine and in part con- 

 tinental, which seem to belong between the highest Cretaceous and the 

 lowest Eocene represented in England. These intermediate deposits have 

 been called Danian, Montian, and other more local names, and have been 

 assigned by some geologists to the Cretaceous, by others to the Tertiary, 

 and by still others part to the Cretaceous and part to the Tertiary. The 

 limits that have been given to Danian and Montian and the various senses 

 in which these names have been used by different geologists show almost 

 as great variety in usage as our own much abused term Laramie has re- 

 ceived. It is interesting to note that the latest European dinosaurs come 

 from formations concerning whose classification perfect agreement has 

 not yet been reached. 



All will agree, I think, that when two contiguous systems as originally 

 defined are separated by an unconformity or there is other evidence of a 

 break in sedimentation, it is probable that intermediate deposits will be 

 found in some part of the world, and that when found, if they are sub- 

 ordinate in character, they should be assigned in each case to the system 

 to which they are most closely related. The practical difficulty lies in 

 demonstrating tlie close relationship, and that difficulty is not removed 

 by applying new criteria and new principles of classification or by rede- 

 fining a system to make it fit local conditions in a restricted distant area 

 without consideration of the type section. 



Contact between mahtne Crktaceous anp marine Eocene in 

 N'oRTH America 



In America, as in England, wherever marine Cretaceous is directly 

 overlain by marine Eocene there is no difficulty in recognizing the bound- 



