LESQUEKEUx.] EVIDENCE OF AGE OF LIGNITIC GROUP. Zbld 



tance; and, indeed, the Vancouver flora may show, in its details, marked 

 points of dissimilarity to that of the Mississippi. But, one of the prom- 

 inent characters of the Lower Liguitic is the predominance of Palms, 

 and we find it manifest in all the localities named above. Indeed, 1 have 

 found remains of Palm, especially of Sabal, whenever I have seen Lower 

 Lig'uite beds; and, as it has been remarked formerly, /S'a&a? Grayana has 

 been observed on specimens from Vancouver, Point of Eocks, Golden, the 

 Mississippi, &c. With this there are, in all these floras, a predominance 

 of subtropical forms, and the absence of northern types, rendering more 

 evident their correlation in time. Suiflcient details have been given on 

 the species of the group, and on their distribution, in Dr. Hayden's 

 former report (1873), p. 378 to 390. 



The group of plants of the Evanston division has, as yet, no remains 

 of palm -leaves, but fruits doubtfully referable to the Palm family; 

 with this it has some of its species of leaves represented at Golden, 

 others at Carbon. The general character of its flora does not indicate 

 as high an average degree of temperature as that of the Lower Lignitic. 

 The group has been separated, as an intermediate one whose relation is 

 not positively fixed now. According to Professor Cope's description, 

 bones of Eocene vertebrate animals have been found in connection with 

 it. Its true horizon may be rendered more definite by further discoveries. 

 But in the group of Carbon the general character of the flora is evident, 

 and its relation to the Miocene of Europe and of Greenland is exposed, 

 not only by this general kind of related facies, but also by a number of 

 species, like Platanus aceroides and Guillelmm,* Acer, Populus arctica, 

 Taxodium duMum, Ahius Kefersteinii Betula, Quercus, Corylus, indicating, 

 together with the total absence of Palms, a marked cliiference in the 

 climatic circumstances governing the flora and that of the Lower 

 Lignitic group. This difference, also, is not remarked at Carbon only. 

 It is reproduced in the same degree, by general affinity and identity of 

 species, in the flora of Coral-Hollow, San Joachin County, and of Con- 

 tra Costa, south of Mount Diablo, California ; of Bridge Creek, John 

 Day Valley, and of Blue Mountain, Oregon ; of Bellingham Bay, of 

 Alaska, as established by Heer's flora of that country, and therefore fol- 

 lowed northward from Carbon to Greenland. Some of its types are so 

 definite that a single specimen of a species of Acer or Platanus would 

 suffice to positively identify this group as Miocene, just as a few spec- 

 imens of Quercus fitrcinervispvoyed the Eocene age of the Cascade Mount- 

 ains of Oregon, whose formations were at first supposed to be Post- 

 Tertiary or of recent origin. 



A few words more will be sufiicient to answer the other objections 

 recorded at the beginning of this paper against the value of vegetable 

 paleontology in its application to geology for the determination of the 

 age of the formations. We know now well enough that remains of 

 fossil plants are abundantly found in the land deposits of this continent. 

 The result obtained from the onset of American researches in vegetable 

 paleontology let us surmise what an immense amount of documentary 

 data the after-coming geologist shall be able to gather in the same 

 field. The authority of animal-remains shall continue undoubted as far 

 ■as it refers to marine formations. But when land formations are to be 

 considered, the authority should, when evident, be accepted as decisive. 



* The fragment of leaf found in connection with the bones of the Saurian at Black 

 Butte, and considered, from the character of nervation of the middle of the leaf, the only part 

 preserved, as doubtfully referable to P. Guillelma ? Vfas identified from better specimens, 

 showing the outlines of whole leaves, as a new species of Viburnum, described in this paper as 

 Viburnun platanoides. 



