WARD] THE VIRGINIA AREA. 261 
One of the most important purposes subserved by this work is that 
of correcting the determination of the forms that had previously been 
described. Professor Fontaine undertook, in the preparation of this 
work, to make careful comparisons of all the forms in his collection 
with the figures that had already been published, and he went to great 
pains to indicate those species occurring in beds of similar age in 
Europe and other parts of the world which were capable of being com- 
pared with those of Virginia. This was possible in a considerable 
number of cases, and we are, therefore, placed in a position to consider 
the age of this formation from the point of view of. vegetable paleon- 
tology in its relation to older and better-established deposits. In view 
of its importance, Professor Fontaine’s work must, therefore, serve as 
the basis, or general starting point, from which not only this discus- 
sion but the general discussion of the Triassic plants of North America 
will proceed: 
Professor Fontaine did not restrict his investigations and compari- 
sons to the Oolite of Yorkshire, as Rogers and Bunbury had done, but 
availed himself of all the extant literature upon the subject relating to 
the fossil plants of all the formations of Europe and other parts of 
the world whose geological position is not far removed from that to 
which the American beds had already been referred. The important 
researches of August Schenk upon the fossil flora of the Mesozoic of 
Bavaria, especially of Franconia, in the vicinity of Baireuth, pre- 
viously known to him only imperfectly through Count von Minster’s 
Beitriige and two papers by D. Brauns, had opened up a new and 
important field and furnished a very much broader basis for the study 
of the analogous floras the world over. Nathorst had also contributed 
in an important way to the study of the Rhetic flora of southern 
Sweden. Heer had investigated the Oolitic floras of the Arctic regions 
and Siberia, and Feistmantel had published his exhaustive works on 
the Gondwana system of India. All these, and other important works, 
were consulted by Professor Fontaine, so that he was in position to 
revise and correct the works of Rogers, Bunbury, Emmons, and 
Hitchcock upon the fossil flora of the American Mesozoic. 
It was thus found that the Virginia Mesozoic flora did not corre- 
spond with anything like the same completeness as had been supposed 
to the Oolite of Yorkshire. Many of the most important species 
which had been depended upon to establish its Oolitic age were dis- 
covered to have been wrongly named and to belong to different genera 
from those to which they had been assigned. 
This revision operated in two directions, viz: primarily, in showing 
that those who had regarded the Richmond coal field as Carboniferous 
or Permian, or had supported their views upon the supposed discov- 
eries in these fields of such Carboniferous plants as Calamites, Sigil-— 
laria, and Lepidodendron, were mistaken in these determinations, and 
