GEOLOGICAL SURVEY OF THE TERRITORIES. 383 



With these, in specimens of Dr. Hayden and Dr. Leconte : 

 Lastrcea (?) dentata, Lesqx., Golden City, Colorado. 

 Magnolia tenuinervis, Lesqx., Golden City, Colorado. 



And from Dr. Hayden's specimens : 

 Platanus aceroides, Heer, Bock Creek, Wyoming. 

 Populus attenuata, Al. Br., Rock Creek, Wyoming. 

 Populus subrolundus, Lesqx., Rock Creek, Wyoming. 

 Populus cequalis, Lesqx., Rock Creek, Wyoming. 

 Quercus acrodon, Lesqx., Rock Creek, Wyoming. 

 Quercus Haydenii, Lesqx., Rock Creek, Wyoming. 

 And fragments of Acer and Populus, species undeterminable. 



The group of plants from Mississippi has a more recent facies than 

 the cretaceous leaves of Nebraska. Except the beautiful pinnate palm, 

 (Calamopsis,) distantly related to species now living in equatorial re- 

 gions, and a remarkable Salisburia, which does not in the least resemble 

 the only remaining species now living in China, most of its genera are 

 represented here at our time, and a number of its species are allied to 

 living ones. Some others, like Quercus Lyellii, Q. clilorophylla, Banksia 

 Helvetica, Sapindus undulatus, are considered as identical with species 

 of the miocene of Europe, and this all, therefore, indicates with the 

 miocenic age a nearer relation than that marked by the characters of 

 the cretaceous flora of Nebraska and Kansas. This, however, is not a 

 positive evidence of contemporaneity, and it is probably right that the 

 strata where these fossil plants were obtained should be considered as 

 pertaining to the eocene, or even to the upper cretaceous. Indeed, Dr. 

 Leconte's species from Raton Pass are not less miocenic in aspect, for, 

 except the numerous fragments of an Abietites, analogous to remains of 

 the same kind from the European cretaceous, all the genera are repre- 

 sented at our time. From the animal remains, however, found in con- 

 nection with the coal-bearing strata of Raton Pass, Dr. Leconte consid- 

 ered them as cretaceous.* If it is right, from what we have seen of its 

 fossil flora, the Marshall's Coal should be admitted also as of cretaceous 

 age, as the specimens from both localities have plants apparently iden- 

 tical — Ginnamomum affine, Echitonium 8opliia3, Juglans Leconteana. 

 These specimens are indeed very incomplete — mere fragments repre- 

 senting vegetables whose identification is difficult and not absolutely 

 reliable; nevertheless, the flora bears, evidently, the same character 

 at both localities, as its facies also is related to that of the Mississippi 

 flora. The character is far different from that of our true miocenic 

 flora, as it is indicated by the small group of plants obtained by Dr. 

 Hayden at Rock Creek, Nebraska; for hereon six species only there 

 are two identical with miocenic species of Europe, and five are closely 

 allied to species of our Eastern North American forests. One only, the 

 beautiful Quercus Haydenii, is related to species of our Western coast. 

 The specimens of Rock Creek are mostly perfect remains of plants easily 

 studied, and their characters undoubtedly ascertained. 



No less miocenic in their characters, though of different family rela- 

 tions, are the remains of fossil plants obtained by Dr. F. V. Hayden in 

 his last exploration, and just now received for examination/ These 

 specimens merely belong to two strata ; those labelled Henry's Fork. 

 Muddy Creek, and Black Fork being on a kind of hard, silicified lime- 

 stone, with remains of the same species of plants, and therefore indi- 



* Notes on the Geology, &c, from Smoky-Hill River, Kansas, to the Rio Grande, by 

 J. L. Leconte, 1868. Columbus, 7th January, 1871. 



