ANALYSIS OF THE DAKOTA GROUP FLOKA. 235 



Senonian, I have found nine species of Quercus, among tliem five of Diyo- 

 phylluiu, all more or less closely related to species of the Seuouiau of Belgium 

 and Westphalia; then Dawson describes Quercus Victoria, from Vancouver 

 Island, and I have recorded three species more from the specimens collected 

 by Dr. Evans in the same locality. This gives us forty species of Quercus 

 already known from the North American Cretaceous, without counting those 

 in Dr. Evans's collection, the descriptions of which have never been pub- 

 lished. We have besides two species of Fagus from the Dakota Group and 

 one from the Milk River series of Canada, described by Dawson. From 

 different stages of the Laramie Group, Prof Ward has four species of 

 Quercus and as many of Dryophyllum, while I have described from local- 

 ities referable to the Laramie Group ten species of Quercus, four of which 

 pertain also to the Miocene of Europe, and two of Dryophyllum. We have, 

 besides, from the Green River Group eight species of Quercus, one only 

 exclusively American, one of Fagus, and one of Castanea. Then from 

 Miocene formations of Alaska, Oregon, the auriferous gravel deposits or 

 chalk bluffs of California, four species of Fagus, three of Castanea, and 

 twenty-five species of Quercus are I'ecorded. 



On these described vegetable remains it will be remarked that the 

 affiliation of the divers types observable in the oaks of North America, is 

 recognized from the Cenomanian upwards, in a number of species. For 

 example, the Chestnut oaks in Q. primordialis and Q. latifolia of the Dakota 

 Group; Quercus Rinkiana Heer, Q. Warningiana Heer, Q. thulensis Heer, of 

 the schists of Atane, while the section of the Salicifolije of Schimper, to 

 which belong the willow and laurel oaks, is represented also in the Dakota 

 Group by Q. eUsworthiarm, the beautiful Q. Wardiana Lesq., with Q. salici- 

 folia Newb., all types reproduced by numerous species in the Upper Creta- 

 ceous of Patoot, of Wyoming, of Vancouver Island, and still more by abun- 

 dant forms in the Laramie flora and the different stages of the North American 

 Tertiary. The only types of our living oaks, the most generalh' repre- 

 sented now in the eastern slope of the United States, is not yet recognized in 

 the Dakota Group, and indeed has not been seen in the Cretaceous. It is 

 that of the white and water oaks with sinuate, lobate, or deeply cut lobate 

 leaves. Its first representatives are seen in the Laramie flora, in Q. hicornis 

 Ward, and Q. (mgustiloha Al. Br. This last species, which is found at 

 Golden, is also identified from the Miocene of Europe. In the Miocene of 

 North America the leaves, diversely and deeph- lobate, are still rare. The 

 fine Q. iiseadolyruta Lesq. has been figured in the flora of the auriferous 



