390 Mr. L. F. Ward on Mesozoic Dicotyledons. 
hundred species of dicotyledonous plants ; and it is to be hoped 
that this paper may form a beginning, at least, of the much- 
needed work of acquainting vegetable paleontologists with the 
nature of this remarkable flora. 
The sixth volume of Heer’s ‘ Flora Fossilis Arctica’ ap- 
peared in 1882. In this the Cretaceous flora of Kome and 
Atane are reviewed with fresh materials. While unable to 
find any companions for the solitary Populus of Kome, he adds 
largely to the dicotyledonous flora of Atane. From 33 species. 
in 1874 this flora now rises to 95. In the seventh volume 
of the same work, which unfortunately must now be the last, 
a new Cretaceous flora is announced, that of Patoot, also in 
Greenland, which is regarded as extreme Upper Cretaceous. 
Dicotyledons here abound; and no less than 74 species are 
made known in Heer’s work. 
Within the past few months an important paper has been 
contributed to the Royal Society of Canada by Principal 
Dawson *, in which 30 species, mostly new, from two distinct 
horizons of the Cretaceous of British Columbia, are described 
and figured. 
Lastly, I am able to add to this enumeration one of the 
most important works that has ever been produced on vege- 
table paleontology, but which is still unpublished, though 
now ready for the press. I refer to Mr. Lesquereux’s ‘ Cre- 
taceous and Tertiary Floras,’ which is to form the eighth 
volume of the series of quartos of the U.S. Geological Survey 
of the Territories in charge of Dr. F. V. Hayden. In this 
work the author again exhaustively reviews the entire subject 
of the American Cretaceous flora, and we find the number of 
Dicotyledons thus far yielded by the Dakota Group to have 
reached 167. In his table of distribution he attempts to 
embrace the flora of the entire Cenomanian Formation, to 
which he doubtless rightly believes our Dakota Group to 
belong. The total number of Dicotyledons thus marshalled 
is 812. Large as these figures seem, there is much reason to 
believe that they fall in both cases considerably below the 
actual state of science at the present time, as will be seen by 
the tabular statement given below. 
If we now turn from this strictly chronological enumeration 
to a consideration of the stratigraphical position in which 
these plants have been found, as indicating their relative age, 
we shall find the results no less interesting than is the history 
of their discovery. 
The various countries of the globe where geology is studied 
* ‘Transactions, pp. 15-34, pls. 1.—viii. 
