336 OLDER MESOZOIC FLORAS OF UNITED STATES. 
was supposed to be the oldest member of the Cretaceous system on this continent. 
The question in my mind has been: Are they Jurassic or Triassic? No Jurassic plants, 
unless these are such, have been found in America, and the Triassic flora of Abiquiu 
and Sonora is Keuper, so there is a possibility, not to say probability, that we here 
get our first glimpse of the flora which covered the land while the Jurassic lime- 
stones of the Black Hills and the Wasatch were accumulating in the sea, and the 
Atlantosaurus beds were filling up fresh-water lakes around which was land that sup- 
ported a luxuriant vegetation. This was so because the Jurassic fresh-water beds 
contain the remains of the largest herbivores known. Atlantosaurus was 100 feet or ~ 
more in length, stood 30 feet in height, and must have consumed several tons of vege- 
table tissue per day. This shows how much we have to learn in regard to the vege- 
tation of our continent in geological times. Knowing the herbivorous character of 
the great Jurassic Dinosaurs, I have been on the lookout to find traces of their food, 
but the Atlantosaurus beds, where I have examined them, contain no plants. 
Somewhere they will be found, however, and I envy the man who first gets a view 
of them. 
The localities where I have seen the fresh-water Jurassic strata are near Canyon 
City in Canyon Pintado, north of the Sierra Abajo and in South Canyon, near Glen- 
wood Springs. In none of the localities did I find any remains of plants, but I had 
very little time to look, and I beg you will make a note of these places, as well as that 
of the Moqui plants, as deserving of further search. 
The so-called Jurassic florula lies in No. 15 of the section on pages 84 and 85; all 
above that is unquestionably Cretaceous. No.14is Dakota, asis proven by its numer- 
ous dicotyledonous leaves and by its relation to the overlying shales, which repre- 
sent the Colorado group and contain its characteristic fossils. No. 12 of the section 
on page 85 contains numerous plant remains, some of which are represented on pl. iii, 
but they have nothing to do with the flora found in the clays and lignites (No. 15) 
which lie below all the strata of the Moqui table-lands.. Only the plants of which the 
figures are numbered 1, 2, 3, 4, 4a on pl. iii are from this horizon. None of the plants 
taken from this stratum have been found elsewhere, so I can not say to-day any more 
than when my Colorado report was written whether this florula is Jurassic or Triassic. 
I have never asserted that it was one or the other, and no one else is warranted in 
taking any other ground than I took in that report, viz, that further collections must 
be made from this deposit before the question can be decided. I hope you will keep 
the locality in mind and some time be able to send one of the employees of the Geolog- 
ical Survey there and gather more material. I shall be delighted if the flora of this 
deposit shall prove to be Jurassic, for as yet we have not obtained a glimpse of the 
great flora that must have prevailed on this continent during the Jurassic age and 
which afforded subsistence to the great herbivores, Atlantosaurus, Stegosaurus, etc. 
Soon after this I had some correspondence with Professor Fontaine 
relative to the probable affinities of the plants figured in the Ives re- 
port. He made a careful examination of the figures and the text, and 
wrote me as follows: 
I have examined carefully the figures of the fossil plants described by Dr. New- 
berry in the Ives report on the Colorado River of the West, which are given on 
pl. ili, figs. 1-4, and have read all that Newberry says about them. I should say 
decidedly that they are neither true Triassic nor Rhetic in age, but beyond this I can 
not speak with conviction. There is not enough material figured to fix the character 
of the flora, and the plants figured are not identical with any described species known 
1This prediction has now been fulfilled by the discovery of the cycads and fossil wood described 
in this paper, L. F. W. 
