SURVEY OF COLORADO AND NEW MEXICO. 97 



T UPPER EXD OF PURGATORY CANON, DR. LECONTE. 



1. Bliamnus dbovatus, sp. nov. All tlie specimens are from the same place, and all con- 

 tain fragments of the same species, and none of any other. This species is pecnliar by 

 the form of the leaves; it has the character of a Bliamnus bnt the secondary nerves are 

 closer and more numerous than in any other species of the genus, even more so than in 

 a Bercheniia. I do not know of any fossil plant comparable to this. 



From this short report on your fossil plants examined till now, it is easy to draw 

 some general conclusions. 



From Rock Creek we have only six species. Two are identical with species from the 

 miocene of Europe, and one of them, Plataniis aceroides, is not distinguishable from our 

 P. occidentalis. Two other species are closely allied to European tertiary species. And 

 of the two others, one is an American type related to Querctts 2)n)ioides, still in our flora, 

 the other a peculiar and lost type. The appearance of this florula is quite modern. 

 This may be the result of geogTaphical circumstances. Poplars and buttonwoods live 

 together in the bottoms of rivers, and therefore I may mistake in believing this Rock 

 Creek formation more recent than that of Marshall's. In any case it is certainly tertiary 

 and has no plants of an older formation. 



In Marshall's (coal beds) we fiud only ten species of fossil plants, two Quercus and one 

 EcMtonium apparently identical Avitli miocene species of Europe, one Bhamnus , closely 

 related to a living species of ours, and at the same time to a fossil species of the lignite of 

 Mississippi, one Cormis, one Jiiglans, and one Cinnamomum, all related to miocene species, 

 and the last one also closely allied to a species of the Mississippi tertiary; undetermin- 

 able leaves of maple, seeds of the same genus, a Lygodiumand an undeterminable Phi/l- 

 lites complete the list. These plants have, therefore, all of them, the character of ter- 

 tiary plants. The general asi^ect of the Marshall coal flora is that of the Mississippi 

 lignite, which I consider as either lowest miocene or eocene. In this I am much pleased 

 to fiud my views so well agreeing with yours. 



The materials obtained from the strata of Golden City, Raton Pass, and Purgatory ' 

 Canon, are too scanty to permit considerations in regard to the geological positions of the 

 strata which have furnished them. No Ahies has yet been described from tertiary strata, 

 but with these broken remains of a conifer of uncertain genus, the shale of Raton Pass 

 has a Berchemia, which is a tertiary plant, and a leaf of EcMtonium, and one of Cinna- 

 momum identical with specimens found at Marshall's. 



In conclusion, I beg leave to say, that wliile I have the most ijrofound 

 respect for the labors of my fellow g-eologists in the same field, I differ 

 with them somewhat, simply because the evidence, to my mind, points in 

 a different direction. In various portions of the Laramie Plains, Col- 

 orado, Eaton Hills, &c., I have observed between the well-defined cre- 

 taceous and tertiary beds a gToup of strata composed of thin layers of 

 clay, with yellow and gray sands and sandstones, which I have called 

 transition or beds of passage. If in these beds I were to find some purely 

 marine remains, oven inoceramus or baculites, I should then call them 

 transition beds, in accordance with the evidence of the continuous un- 

 interrupted growth of the continent from the cretaceous through the 

 tertiary period. There is no proof, so far as I have observed, in all the 

 western country of true non-conformity between the cretaceous and lower 

 tertiary beds, and no evidence of any chang-e in sediments or any catas- 

 trophe sufficient to account for the sudden and apparently complete de- 

 struction of organic life at the close of the cretaceous period. In all 

 my examinations of the coal formations over so vast an area, I have never 

 yet seen a trace of a cretaceous fossil in any strata above the coal. One 

 of the most important practical questions for solution in the west is, 

 whether these coals can be rendered useful for smelting ores. To aid in 

 the solution of this question, I have appended the following analyses of 

 the coals from various portions of the West. 



Mr. J. P. Carson, my assistant on the United States geological sur- 

 vey, 1888, made the following analysis of a fair specimen of the coal 

 from the Carbon mines, Kortheru Pacific railroad. 



Moisture at lOQo F 11.60 



Volatile combustible matter 27.68 



Fixed carbon 51.67 



7 a s 



