158 



SHORTER CONTRIBtTTIONS TO GENERAL GEOLOGY. li>21. 



Miigothv, as a great many upper Raritau spe- 

 cies survived into Magothv time. There are 

 nine species common to the Woodbine and 

 Bhick Creek formations, but six of these are 

 widespread and king-lived forms without espe- 

 ciid significance. Five of the Woodbine species 

 are common to the Eutaw flora, and one ex- 

 tentls Its liigh as the Riidey formation of the 

 eivstern Gulf area. 



RELATION TO THE FLORA OF THE DAKOTA 

 SANDSTONE. 



The llora of the Dakota sandstone is very 

 large, embracing over 400 described species. 

 It is also very obviously not ail of the same age, 

 but outside of certain areas in Kansas and Ne- 

 braska no data are available for determining 

 what part of Dakota flora came from beds that 

 merit that term and what part came from beds 

 sine* discovered or suspected to be different. 



Of the 4.3 Woodbine plants .30 arc species of 

 the Dakota sandstone flora. The community 

 of facics is thus very great, and it is significant 

 that of these 30 common species all but 10 arc 

 forms which their range in other formations 

 proves to represent what for want of a better 

 term might be termed the true Dakota flora, 

 and tiiree of these 10 are only doubtfully deter- 

 mined from the Morrison formation in Colo- 

 rado " and these three occur definitely in the 

 Tuscaloosa, Raritan, and Magothy formations, 

 so that really 2-3 of the Woodbine plants are true 

 Dakota forms. I regard ttie Woodl)in(> as syn- 

 chronous with this undelimited Dakota sand- 

 stone, which I regard as bearing the same rela- 

 tion to the Benton as the Woodbine does to the 

 Eajrle Ford and the Tuscaloosa docs to the 

 Eutaw. 



RELATION TO THE FLORA OF THE CHEYENNE 

 SANDSTONE. 



The relations ix-tween the Woodbine flora 

 and that of the Mentor formation of central 

 Kansas are unknown anrl will remain so imtil 

 the Mentor flora is carefully collected and 

 studied. The Cheyenne sandstone of soul linn 

 Kansas contains a considerable flora, re<<'ntly 

 ^ studied by me, but there is not a single species 

 common to the Woodbine and Cheyenne. Al- 

 though both floras consist largely of so-called 

 Dakota forms, some of these in the Cheyenne 



" KnowUcin, K. H., Am. Jour. Hcl., Itbscr., vol. «, pp. 189-lM, 1020. 



sandstone are forms that may have come origi- 

 nally from the imrecognized Cheyenne sand- 

 stone or the supposed <'quivalcnt Mentor forma- 

 tion, and not from the true Dakota sandstone. 

 The majority lack an outside distribution. 



The Woodbine plants, on the other hand, as 

 shown by the comparisons in the preceding 

 sections, are nearly all well-known species of 

 formations of known age of the Coastal Plain. 

 There can not be the slightest doubt that the 

 Woodbine sand is younger than the Chej-enne 

 sandstone and synchronous with the true 

 Dakota sandstone of the Western Interior. 

 The Woodbine is also certainly younger than 

 those beds in the West formerly confused with 

 the Dakota and now Iviiown as the Purgatoiro 

 formation. 



RELATION OF THE WOODBINE FLORA TO 

 FLORAS OF OTHER AREAS. 



None of the Woodl)ine species have been 

 identified in the formations of the Montana 

 group. Eight of the Woodbine species are 

 fountl in the Atane beds and six in the Patoot 

 beds of western Greenland. 



The similarities of the flora to European 

 Upper Cretaceous floras are reasonably close, 

 but these similarities naturally seldom extend 

 to the identical species, and where they do the 

 particular forms are wide-ranging and long- 

 lived species of slight value in precise correla- 

 tion, as might be expected. The Woodbine 

 contains five species common to European beds 

 referred In (he Cenomanian and three addi- 

 tional that are tentatively recognized at this 

 European horizon. .Similarly two species are 

 identical with forms that occur in the European 

 Turonian. None of the species are known in 

 ihv Emscherian of I']uroj)e, although I)fir(il(/iie(i 

 ijisu/niformis of the Woodi>ine is, as its name 

 indicates, very close to the European .Senonian 

 species Dewalquen iiisif/nift Debey. 



The intrinsic character of the Woodiiine 

 flora necessitates considering it as either Ceno- 

 manian or Turonian wlicn judged according In 

 Euro[)ean standards. From its relationshij) 

 with other more extensivi^ fonnations of the 

 Coastal Plain such as the Tuscaloosa and Ma- 

 gothy, in which the evidenc(> is clearer, I Wdiiid 

 be incliiM'd to considi-r (lie Woodbine flora as of 

 Turonian age 



