38G GEOLOGICAL SURVEY OF THE TERRITOEIES. 



REMARKS ON THE SPECIES OE THE SECOND GROUP. 



The flora of group No. 2 seems to be composed of species in pait 

 identical with or closely allied to those of group No. 1, or with those of 

 group No. 3. The species of Spring CaSon have, besides those which are 

 represented in the whole Tertiary, Gymnogramma Haydenii, Abietites 

 dubius, Salisburia polymorpha, Gaulinites Spargafiioides, Ficus auriciilata, 

 or five species considered as Eocene, type of the first group. The same 

 locality has, however, of species represented in the third group, and 

 which are truly Miocene, iSalix angusta, Alnus Kefersteinii, Quercus 

 platania, Corylus 3IcQuarryi, Platanus aceroides, and Juglcms denticulata, 

 or seven species. The flora of Evaustou is mixed in the same way, for it 

 has, in common with the first section, fruits of palms, (no leaves, however, 

 have been found there as yet,) Magnolia Hilgardiana, Bhamnus obovatus, 

 Juglans appressa, J. rhanmoides, or five species; and, with the third group, 

 Fopulus arctica, Betula Stevensoni, Fagus Deucalionis, Platanus aceroides, 

 Acer trilobatum. This intermixture of types might be explained in sup- 

 posing that the specimens of Spring Caiion were obtained from different 

 localities ; but, as we have the sama fades at Evanston, this supposition 

 is groundless. Evanston has an enormous thickness of lignite deposits, 

 separated in a number of beds of pure coal by clay partings, or thin 

 intermediate layers of shale and sandstone. Four beds of lignite, meas- 

 uring altogether 43 feet, are reported in a section of 99 feet*, the middle 

 one, 32 feet thick, being cut by four clay partings. It seems, therefore, 

 that there was at this locality, and perhaps also at Spring Caiion, a pro- 

 tracted formation of lignite beds, continuing, nearly without interrup- 

 tion, fi^om the Lower to the Upper Eocene. 1 am inclined to consider 

 this group No. 2 as Upper Eocene on account of tlie conglomerate beds 

 by which it is overlaid. Its flora has, however, a marked character of 

 its own by a number of species which as yet have not been seen out of 

 it: Salioc Fvanstoniana, Myrica ambigua, Quercus negundoides, Q.FlUsi- 

 ana, Q. Fealei, Ficus Gaudini, Mortis affinis, Platanus dubius, Laurtis ses- 

 silijlorus, Galycites hexapliylla, Carpolithes aracMoides, &c. All the Euro- 

 pean sj)ecies recognized in this group are Miocene. A number of its 

 types, too, mostly found also in the third group, are northern types, 

 arctic or Alaskanian: Phragmites Alaslcana, Fopulus arctica, P. Zad- 

 dachi, Salix Groenlandica, Quercus platania, Gorylus McQuarryi, Fagus 

 antipji, Fraxinus denticulata, Vitis olriM. Taking all together, one-half 

 of this flora is a compound of arctic or of European Miocene species. 



LIST OF THE SPECIES OF THE THIRD GROUP. 



[Abbreviations for names of localities: C, Carbon; W. G., Wahsatch or Wasliakie 

 group; M. B., Medicine Bow; R. C, Rock Creek; P. of R; Point of Rocks; Mo., 

 Miocene ; Gr., Group.] 



Sclerotium pustuliferum, Heer. — C. (*?) 



Halymenites major, Lesqx. — C, (Gr. 1 nnd 2.) 



Taxodium, dubium, Heer. — C. — Mo., (Gr. 4.) 



Sequoia Heerii, Lesqx. — 0. 



Equisetum Haydenii, Lesqx. — 0., (Gr. 4.) 



Phragmites CEningensis, A. Br. — M. B. — Mo., (Gr. 1, 2, 4.) 



Cyperites, species. — P. of R. 



Smilax grandifolia, U. — 0. — Mo., (Gr. 1.) 



Acorus brachystachys, Heer. — W. G., C. — Mo. 



Oanlinites Sparganioides, Lesqx. — C, (Gr. 1, 2.) 



* Dr. A. C. Peale in Hayden's Report, 1871, pp. 194, 195. 



