418 FLORA OF THE LARAMIE GROUP. 



present. Tlie formation described belongs to this lowest Tertiary, 

 beinj;, in l;u!t, an extension of Hayden's Fort Union group, and from 

 analogy may be called Eocene.'''' 



In a more formal paper' pnblished the same year, he also says: 

 "The formation is, however, nndonbtedly an extension of the Great 

 Lignite or I''ort Union gronp of strata of Ilayden, as develo])ed in the 

 Western States and Territories. * * * These strata immediately suc- 

 ceeding the (Jretaceons rocks are the lowest American rei)resentatives of 

 the Tertiary series and have been called for this reason Eocene, though 

 it is im])()S8ibIe to afBrm that their deposit was more than approxi- 

 mately synchronous with that of the Eocene as constituted in Europe" 

 (p. 20). ' 



Keturning to the same subject a year later in his final report of the 

 Northwest Boundary Commission,^ after familiarizing himself with the 

 discussions going on in the United States, the same author adheres to 

 his previous views and remarks: "There seems little doubt, however, 

 that the general tenor of the evidence of these beds, when considered 

 alone, favors tlieir Lower Eocene age. Their exact synchronism with thp 

 European Eocene is a question apart from the present inquiry" (p. 180). 



Early in 1875 Professor Cope, who had examined the vertebrate re- 

 mains sent him by Mr. Dawson from near Milk Eiver, ou the boundaiy 

 of the British possessions, published a note upon them,^ in which he 

 says: "The genus of tortoises Compsemys, Leidy, is peculiar to the 

 Fort Union epoch, while Plastomenvs, Cope, belongs to the Eocene. Its 

 presence in this fauna would constitute an important assimilation to the 

 Lower Tertiary, but the specimens are not complete in some points 

 necessary to a final reference. The species are in any case nearly allied 

 to that genus. There are, however, gar scales included in the collection 

 which closely resemble those of the genus Clastes of the lower Eocenes 

 of the IJocky Mountains. This is empirically another indication of near 

 connection with Tertiary time, but not conclusive, since allied genera have 

 a much earlier origin in Mesozoic time. * • * Nevertheless, the list of 

 species, short as it is, indicates the future discovery of a complete 

 transition from Cretaceous to Eocene life more clearly than any collec- 

 tion yet obtained marking this horizon in the West." 



' Report on tlie Tertiary Lignite Foniiation in the Vicinity of the forty-ninth parallel. 

 By George M. Dawson. Addressed to Capt. I >. R. Cameron, R. A., H. M. Boundary Com- 

 missioner. British North Aineriian Boumlary Commission. Cieologieal Report of 

 Progress for tlio year ISI'i [in ]iarl]. Montreal, 1874. 



•British North Aineriiau Boundary Commission. Report on the Geology and Re- 

 sources of the Region in the Vieinity of the forty-ninth parallel, from the Lake of the 

 Woods to the Rocky Mountains, with lists of plants and animals collected, and notes 

 on the fossils. By George Mercer Dawson, geologist and hotani.st to the Commission. 

 Addressed to Maj. D. R. Cameron, R. A., H. M. Boundary Commissioner. Montreal, 

 1875. 



^Proceedings of the Academy of Natural Sciences, Philadelphia, Jan. Ti, 187.'j, Vol. 

 XXVII, pp. 9,10. 



