L. F. Ward—Mesozoic Dicotyledons. 301 
lowest, we shall see that in the Neocomian, or lowest member, 
no plant remains of the sub-class we have been studying have 
as yet ever been detected.® 
In the Urgonian, or next higher group, one species, Populus 
primeva Heer, has been collected at Pattorfik in Greenland. 
In volume vi of his Flora Fossilis Arctica, which appeared in 
1882, or eight years subsequent to the original description of 
this plant, Heer continued to adhere to this species as well as 
to its anomalous stratigraphical position. 
chiefly of living genera have been described. 
It was formerly supposed that the beds at Blankenburg occu- 
of Heer’s Quedlinburg Flora in his table of distribution of the 
Cenomanian. It is now quite certain, however, that the Creta- 
ceous of the Harz district is much higher, and authorities seem 
to agree in placing it in the lower Senonian. On the other 
hand the upper boundaries of the Cenomanian in France and 
sep- 
arated from each other by a considerable interval. In view of 
upposed Neocomian Dicotyledons of Russia (Eichwald, Lethsea rossica, 
st : (Fl. foss. arct. iii, Theil 2, S. 26) to come 
ding t rict. 
Spitzi rgen to the Gault (L c. = pe van 
i i in the Cretaceous of Haina 
nine new spacies of fossil plants in Lhegecy trap ee 
4 8 n 
(Mém, de lacad. Royale de Belgique, xxxvi, 1867) which 
*rritories, vol. viii. Washington, 1883. 
