564 



HISTORICAL GEOLOGY. 



beds are the Hercynian of Beyrich; and under this name are placed, by 

 Barrois, beds occurring at Erbray in the Lower Loire. They have been 

 identified also in Sardinia, India, China, Australia, New Zealand, and the 

 Argentine Republic. 



LIFE. 



The Wenlock and Ludlow beds abound in fossils, especially the former, 

 which represent nearly the American Niagara group. Evidence of British 

 land plants occurs in the Ludlow beds ; the earliest of British Fishes — 

 species of Fteraspis and Cephalaspis — in the Lower Ludlow; the earliest 

 of Scorpions, in the Upper Ludlow and the Upper Silurian of Gothland, 

 Sweden. 



826-831. 



Fig. 826, Omphyma turbinata; 827, Cystiphyllum Siluriense ; 828, Crotalocrinus rugosus ; 829, Pentamerus 

 Knightii; 830, Grammysia cingulata; 831, a, Pterygotus bUobus. 826, 827, from Edwards and Haime; 

 828, Murchison ; 829, Brown ; 830, Naumann ; 831, Salter. 



Land Plants. — The Pachytheca of Hooker is supposed to be the spores 

 or sporangia of a terrestrial plant (Q. J. G. Soc, xxxviii., 107, 1882). The 

 Denbighshire grits of the Wenlock of North Wales have afforded the Nema- 

 tophyton of Dawson, having loose tubular cells within, supposed to be from a 

 tree of large size, but now admitted to be a Seaweed. The earliest of well- 

 defined ferns has been described by Saporta for the schists of Angers, which 



