378 GEOLOGICAL SURVEY OF THE TERRITOEIES. 



The absence of these types is as remarkable in the Lignitic flora 

 as in the Eocene of Mount Bolca. While the ui^per group of our 

 Tertiary abounds with conifers, AMetmece, 11 species in 81, the 

 Lower Lignitic has only two, one as yet of uncertain affinity, 

 AMetites dubius, and two species of Salisburia, in nearly 200 species ; 

 of the SalicinecB it has only three species, two of which, Salix tahellaris 

 and S. densmervis, both described froui the Mississippi Eocene, are un- 

 certain, the last, perhaps, an Acacia. It has also no species of Acer, 

 none of Betula, Alnus, Catjnmis, Cori/lus, &g, ; no species of Ulmus, 

 except one doubtful, with entire borders ; for it is, indeed, the absence 

 of leaves with dentate or serrate borders which is the more remarkable 

 character of this group as well as of the Cretaceous ; Querciis furci- 

 nervis and Q. saffordi, (perhaps a Myrica,) make with the Viburnum 

 maginatum and it's related species an exception, which is also remarked 

 in the Cretaceous types Q. primordialis and some peculiar leaves with 

 equal teeth turned outside and separated by obtuse sinuses, just of the 

 same form as in this yiburnum of the Eocene. It is not to be denied, 

 as seen in the comparative table, that a number of species of our Lower 

 Lignitic are found in the two following groups of Evanston, Carbon, and 

 even a few in the Green Eiver group. But we have seen the same in 

 the Eocene, even the Lower Eocene flora of Europe, and cannot from this 

 reason admit that our Lower Lignitic flora is not Eocene, because some of 

 its types have passed up to the other groups of the Tertiary. 



§ 2.— DISTEIBUTIOF OF THE FOSSIL PLAI^TTS IN THE DIFFEE- 

 ENT GROUPS OF THE TEETIAEY. 



The succession of the strata of the Lower Lignitic in relation to the dis- 

 tribution of the coal strata and to that of the fossil plants which character- 

 ize the formation is not positively known. The section at the Eaton 

 Mountains near Trinidad records an alternation of sandstone, shale, clay- 

 beds, &c., 300 feet thick, with five beds of lignite, measuring altogether 

 11 feet 6 inches. Here the fossil plants are found in sandy shale at the 

 base of No. 6 or in the upper part of No. 7 (Eeport for 1872, p. 319) in 

 the middle of the section. At Canon City, as indicated by Mr. Clark's 

 section, {loc. cit., p. 323,) the main coal 2 feet 2 inches is overlaid by 

 shale, clay or thin coal, and a sandstone, over which, in No. 15, are found 

 leaves of Sabal and of Platanus Haydenii, about 70 feet above the coal. 

 At Gehrung's coal, near Colorado City, a shale bearing an abundance of 

 Sabal leaves, Ficus, Platanus Haydenii, and Wiamnus, is also from 60 to 

 75 feet above the coal opened near by at the base of a compact sandstone. 

 From Marshall a detailed section has been published by Dr. Hay den 

 in his Eeport for 1869, (second edition, p. 129.) placing the strata bearing 

 fossil plants at No. 22, about in the middle of the section, 200 feet higher 

 than the lower main coal, and about 260 feet from the top. As far as 

 I know, and from the explorations of others, as well as from my own, no 

 other strata bearing identifiable plants have been remarked in this sec- 

 tion. 



At Erie, the coal 8 to 9 feet is worked near the surface ; its soft sandy 

 shale is profusely mixed with remains of plants, which, to my regret, could 

 not be examined sufficiently. They represent a few species of the Lower Lig- 

 nitic of Golden, and also some remarkable vegetable fragments represent- 

 ing species not found elsewhere. As the underlying strata are not known, 

 the position ofthis coal in the Lower Tertiary measures could not be ascer- 

 tained. At Black Butte, the main coal, overlaid by soft shaly sandstone, 

 with fossil plants in abundance, a stratum which, as remarked before, 

 is the equivalent of the Saurian bed, is here apparently at the upper i)art 



