208 The American Geologist. October, i896 
^'^Sequoia lamjsdorjii has been abundantly found in, but is not 
confined to, the Fort Union group, while Papains genatr/'x and 
Uhnus speciosa are typical Fort Union plants. While it is 
manifestly unsafe to place much dependence in sucli meager 
data all the species identifiable belong to or are found in the 
Fort Union group." 
"I have examined the plants from Sweet Grass creek, and 
am unable to identify a single species with entire satisfaction 
as belonging to the Fort Union flora. Four or five species 
appear to be represented as follows: Numerous specimens of 
a conifer that is probably Seqrioirt ffou/sdorfii, but the branch- 
lets are smaller than is usual, with spines, and the leaves are 
much shorter. There are about a dozen specimens of a fern 
that was at first supposed to be Onoclea sen s i.b iii.i< J'oss ills, hut 
more careful study seems to prove that it cannot be this. It 
is undoubtedly quite close to this species, but differs in de- 
tails of vernation. It will have to be described as a new 
species. Associated with this fern are two examples of what 
may be the fertile branches; but in absence of proof connect- 
ing them, it will probably be best to describe them as new 
also. 
•'There is also a very fine dicotyledonous leaf that must have 
been seven or eight inches in length and between four and 
five inches in width. It is broadly ovate in outline, with a 
broad heart-shaped base, and has five palniately arranged 
verns, all springing from the petiole. I am uncertain as to its 
affinities. A number of other dicotyledons are too fragmen- 
tary to admit of even generic determinations. 
"In a general way these resemble Fort Union plants, but 
none of them belong without-question to this flora." 
The strata to which the name of Fort Union was first given 
form the bluffs of the Missouri river in the vicinity of the 
mouth of the Yellowstone. The beds include two horizons, 
lithologically distinct. The locality was visited by the writer 
in company with Prof. C. D. Walcott in August, 1895. The 
bluffs north of the Missouri river near Willow station were 
carefully noted. The lower part consists of light colored 
gray sands with rusty lenses and concretions, forming caps 
that cause picturesque pillars and exposures. There are prob- 
ably 50 to 75 feet of this sandy series exposed, which is 
capped by the clay series and lignites. 
