Cordaites borassifolia, Brongt.
On the whole, this small flora is markedly distinct from that of the Millstone Grit and true coal-formation, from which it is separated by the great length of time required for the deposition of the marine limestones and their associated beds, in which no land-plants have been found; nor is this gap filled up by the conglomerates and coarse arenaceous beds which, as I have explained in “Acadian Geology,” in some localities take the place of the limestones, as they do also in the Appalachian region farther south.
The palæobotanical and stratigraphical equivalents of this series abroad would seem to be the following:
1. The Vespertine group of Rogers in Pennsylvania.
2. The Kinderhook group of Worthen in Illinois.
3. The Marshall group of Winchell in Michigan.
4. The Waverley sandstone (in part) of Ohio.
5. The Lower or False Coal-measures of Virginia.
6. The Calciferous sandstones of McLaren, or Tweedian group of Tate in Scotland.
7. The Lower Carboniferous slate and Coomhala grits of Jukes in Ireland.