46 



LARAMIE FLORA OF THE DENVER BASIN. 



Judging from their respective invertebrate faunae, it 

 would seem impracticable to separate the "Belly River 

 series" from the Laramie and more especially from the 

 ' ' Judith River group' ' on purely paleontological evidence. 



Dawson published several papers on the 

 flora of the "Laramie." In a paper on the 

 Cretaceous and Tertiary floras of British 

 Columbia and the Northwest Territory 52 he 

 gave lists of "Laramie" plants from several 

 localities. He considered the so-called Laramie 

 as equivalent to the Fort Union, and the plants 

 mentioned undoubtedly bear- this out. In 

 1885, in his paper on the Mesozoic floras of the 

 Rocky Mountain region of Canada, 53 he dis- 

 cussed the Belly River and so-called Laramie 

 series, which he then failed to differentiate. He 

 divided the "Laramie" into three "groups" — 

 the "Lower Laramie," which embraced the 

 St. Mary River series of George M. Dawson; 

 the "Middle Laramie," or Willow Creek series 

 of Dawson; and the "Upper Laramie," or 

 Porcupine Hill series of Dawson. To judge 

 from the lists of plants given, it would seem 

 that there had been some mixture of horizons 

 when the collections were made. 



Dawson's third paper, on the fossil plants of 

 the Laramie formation of Canada, 54 introduced 

 still another set of terms. He stated that the 

 "Laramie" of Canada occurs in two large 

 areas west of the 100th meridian and separated 

 from each other by a tract of' older Cretaceous 

 rocks. The eastern of these areas extends for 

 some distance along the United. States bound- 

 ary between the 102d and 109th meridians 

 and northward nearly to the parallel of 51°. 

 Here, he said, the lowest beds of the "Laramie " 

 rest on Fox Hills and are overlain by Miocene. 

 He continued: . ' 



They are undoubtedly continuous with the Fort Union 

 group of the United States geologists on the other side of 

 the international boundary, and they contain similar 

 fossil plants. They are divisible into two groups — a 

 lower, mostly argillaceous, and to which the name of 

 "Bad Lands beds," may be given from the "badlands" 

 of Wood Mountain, where tkey are well exposed, and an 

 upper, partly arenaceous member, which may be named 

 the Souris River or Porcupine Creek division. In the 

 lower division are found reptilian remains of Upper 

 Cretaceous type, with some fish remains more nearly akin 

 to those of the Eocene. 



The western area is of still larger dimensions 

 and extends along the eastern base of the Rocky 



a! Eoy. Soc. Canada Trans., vol. 1, sec. 4, pp. 15-34, 1883. 

 » Idem, vol. 3, sec. 4, pp. 1-22, 1885. 

 M Idem, vol. 4, sec. 4, pp. 19-34, 1887. 



Mountains from the United States boundary 

 to about the 58th parallel of latitude and thence 

 eastward to the 111th meridian. In this area 

 three divisions of the beds are made : 



(1) The Lower Laramie, or St. Mary River series, 

 corresponding in its character and fossils to the Lower or 

 Bad Lands division of the other area; (2) a middle divi- 

 sion, the Willow Creek beds, not recognized in the other 

 area; (3) the Upper Laramie or Porcupine Hills division, 

 corresponding in fossils and to some extent in mineral 

 character to the Souris River beds of the eastern area. 



The paper enumerated 51 forms of plants, 

 of which 10 were found in the "Lower Laramie" 

 and the remainder in the "Upper Laramie," 

 with about 8 in common. It is essentially a 

 Fort Union flora. 



Several years later Dawson 55 published 

 another short paper dealing mainly with plants 

 from Mackenzie River, which he showed are 

 to be identified with the Fort Union. 



In 1893 Whiteaves 58 delivered a presidential 

 address before the Royal Society of Canada, 

 on "The Cretaceous system of Canada," 

 which was mainly an enumeration of the fossil 

 forms that had been recorded from the several 

 members of the Cretaceous. Although he did 

 not specifically so state, it is evident that he 

 included in the "Laramie" both the "Lower 

 Laramie" and "Upper Laramie" of previous 

 writers, and of (jourse it was all regarded as 

 Cretaceous. 



In 19,08 D. P. Penhallow 57 presented an 

 elaborate "Report on Tertiary plants of British 

 Columbia," which was based primarily on 

 collections made by L. M. Lambe in 1906 but 

 which was made to include all previous work 

 by Dawson and others within this area. If 

 Penhallow had taken occasion to revise the 

 earlier work, this could have been made a very 

 valuable contribution, but unfortunately he 

 made no attempt at revision and the lists were 

 compiled without change. The "Laramie" 

 here was said to include only the "Upper 

 Laramie" (Paskapoo of Tyrrell), which was 

 made synonymous with Fort Union, lower 

 Eocene, and "Lignite Tertiary." The conclu- 

 sion of Sir William Dawson that the "Upper 

 Laramie" is undoubtedly of Tertiary age was 

 confirmed. 



65 Dawson, William, On fossil plants from the Mackenzie and Bow 

 rivers: Eoy. Soc. Canada Trans., vol. 7, sec. 4, pp. 69-74, 1889. 



M Whiteaves, J. F., Roy. Soc. Canada Trans., vol. 9, sec. 4, pp. 1-19, 

 1893. 



» Canada Geol. Survey Mem-. 1013, pp. 1-167; 1908. 



