394. Mr. L. F. Ward on Mesozoic Dicotyledons. 
includes the species of Heer’s Quedlinburg flora in his table 
of distribution of the Cenomanian. It is now quite certain, 
however, that the Cretaceous 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 elsewhere are somewhat imper- 
fectly established. For this and other reasons I have felt 
justified in relegating the few species that have been classed as 
Turonian to the Cenomanian, of which great group they seem 
to be but straggling outliers. 
In the Senonian, both in Europe and in British Columbia, 
two quite distinct horizons for fossil plants seem to occur, 
separated from each other by a considerable interval. In 
view of this I have attempted to divide this group into two 
horizons, and am thus able to show the Lower and Upper 
Senonian separately. From the Lower Senonian we have 
about eighty species and from the Upper about one hundred 
and eighty. 
The following Table exhibits the number of dicotyledo- 
nous species thus far recognized in each of the groups of the 
Cretaceous for the four principal geographical areas within 
which they have been collected :— 
Cretaceous Dicotyledons. 
SS 
F -: 5 E 
Geological Position. A FI < 2) 
ay | a 3 ; 
z 3 = = 3 
5 = cee Ss 
ss & ea 5 a 
Upper Senonian .... 81 74. 24 179 
Lower Senonian .... 67 14 81 
AORN Gono boo aos 5 pd Ee ie 
Cenomanian ati 53 114 ae 
Dakota Group : & 184 = 
(alice ee ero eres fe in or a ae 
Wivanran® 6. 645.4 65 eh 1 Ag i: 1 
INeocomisn, ....)..6.6. bb 6 
Mota 201 189 38 184 612 
As all the plants with which we are here concerned are 
found in the Cretaceous, some may be surprised that this 
paper should have been entitled Jesozoic rather than Creta- 
