Fig. 1.—Protannularia Harknessii (Nicholson), a probable Rhizocarp of the Ordovician period.
If we ascend into the Upper Silurian, or Silurian proper, the evidences of land vegetation somewhat increase. In 1859 I described, in “The Journal of the Geological Society” of London, a remarkable tree from the Lower Erian of Gaspé, under the name Prototaxites, but for which I now prefer the name Nematophyton. When in London, in 1870, I obtained permission to examine certain specimens of spore-cases or seeds from the Upper Ludlow (Silurian) formation of England, and which had been described by Sir Joseph Hooker under the name Pachytheca. In the same slabs with these I found fragments of fossil wood identical with those of the Gaspé plant. Still later I recognised similar fragments associated also with Pachytheca in the Silurian of Cape Bon Ami, New Brunswick. Lastly, Dr. Hicks has discovered similar wood, and also similar fruits, in the Denbighshire grits, at the base of the Silurian.[K]
[K] “Journal of the Geological Society,” August, 1881.
Fig. 2.—Nematophyton Logani (magnified). Vertical section.
Fig. 3.—Nematophyton Logani (magnified). Horizontal section, showing part of one of the radial spaces, with tubes passing into it.