LIGNITE WITH FOSSIL PLANTS. 83 
the strata were so imperfect, that I was able to obtain only a very fragmentary and imperfect 
series of specimens. Such as they are, however, they give a very appetizing glimpse of the 
interesting flora there buried. It is to be hoped that before long some one will visit this locality, 
with ample time and means to make a complete collection of all the species it includes. 
The descriptions of the plants procured from this deposit are given in detail in the chapter 
on paleontology. It will be seen that the species represented are all considered new, but are 
closely allied to some of those most characteristic of the Jura and upper Trias of Europe. 
With the amount of material we have as yet procured from this locality, we are hardly pre- 
pared to discuss the question whether this bed of lignite belongs to one or other of these forma- 
tions. The plants of both are very similar, so much so that they are included in one flora 
by Brongnart-—‘‘ the flora of the Jurassic epoch.’’* 
While there is so much difficulty in separating the plants of the Keuper from those of the 
Lias in Europe, the effort to do so here, where they are all specifically different, is nearly hope- 
less. It is almost certain, also, that when we have collected all the species contained in these 
strata we shall still be unable to draw this European line clearly and sharply through them. 
In determining the parallelism of strata in different parts of our own continent it is probable 
these plants will be of great value, as they enable us to fix the lower limits of the Cretaceous 
series, and give us paleontological data for detecting the presence of the American Jurassic 
wherever developed. 
Calling this florula Jurassic, as Brongnart would do, the practical bearing of its discovery on 
the mooted questions of the existence and extent of Jurassic rocks in New Mexico is less 
important than might have been anticipated, from the fact that they are restricted, as far as at 
present observed, to an exceedingly unimportant member of the geological series. It seems 
scarcely possible, however, that this coal seam can be the only representative of a great forma- 
tion; and there is every reason to believe that we shall ultimately find evidence which will lead 
to the union with it of some of the associated strata. 
The sandstones, shales, and limestones lying above also include many beds of lignite closely 
resembling this, and on lithological grounds would be appropriately grouped with it. In fact, 
they have been considered Jurassic, and the only Jurassic rocks in this region, by the geologist 
who claims to have discovered the representatives of this formation in New Mexico. Unfortu- 
nately, however, for that classification, immediately over the thin stratum of yellow sandstone 
which overlies the coal are beds of clay shale with bands of limestone, in which are unmistak- 
able Cretaceous fossils. It is, therefore, quite evident that the Jurassic formation cannot be 
extended in this direction, and there is no alternative left but to consider the coal seam, if 
Jurassic, the sole representative of the Jurassic series, or to combine with it some portion of 
the underlying variegated marls, which for this purpose must be abstracted from the Trias of 
Mr. Marcou. 
Perhaps future explorations will furnish the means for defining the limits of the formations 
which fill the interval between the Carboniferous and Cretaceous rock, but it has seemed to me 
doubtful whether an effort to identify the strata composing the geological series of this far off 
region, in another hemisphere, with all the subdivisions of the formations found in Europe, 
would be crowned with entire success. We have everywhere evidence that the diversity of 
fauna and flora exhibited by the different portions of the earth’s surface at the present time, as 
well as the variety in the physical characters of all mineral deposits now forming, were fore- 
shadowed by similar phenomena during the different geological ages. 
MOQUI COUNTRY. 
Cretaceous rocks.—At the Moqui villages a mesa rises abruptly from the surface of the varie- 
gated marls, presenting a striking contrast, both in physical aspect and geological structure, to 
®Tab. des Gen. des Veget., Foss., Dict. de Hist. Nat., vol. XII, p. 151. 
