556 MANUAL OF NATURAL HISTORY. 



Nerita, are the most abundant of the carboniferous 

 gasteropods. Polypi/era of the genera Cyathophyl- 

 lum, Lithodendron, Syringopora, and Catenipora, 

 are numerous in the limestones. 



The remains of ancient plants are numerous in 

 this formation; the gigantic Tree Ferns, now confined 

 to warm regions, constituted nearly two-thirds of 

 the whole known fossil flora, and seem, at that pe- 

 riod, as in New Zealand at the present day, to have 

 replaced the graminaceous tribes, and to have co- 

 vered extensive tracts with their delicate fronds 

 and arborescent forms. Besides, however, the vast 

 abundance of Ferns, large Coniferous trees related 

 to species of warm climates, gigantic Lycopodiacece, 

 and tribes related to the Cactacece and Ricinacece, 

 were prevalent. Palms, and other monocotyledons, 

 also Catamites, referred by some to the Horsetails, 

 are also noticed. 



Among the Filices may be discovered the round- 

 leaved Cyclopteris ; twenty-four species of Nerve- 

 leaved fern, Neuropteris ; the elegant Tooth-leaved 

 fern, Odontopteris ; sixty species of Embroidered 

 fern, Pecopteris, with beautiful tripinnate leaves ; 

 the Spear-leaved feYn,Lonchopteris, and the Fissured 

 fern, 8chizopteris. Among the Club-mosses we find 

 the Lycopodites with pinnate branches, the Sala- 

 yinites, with dichotomous stems, and the Lepido- 

 dendron and Ulodendron, with the branches co- 

 vered with scale-like leaves. Besides these, the 

 Lepidostrombus, forming ovate cones of imbricate 

 scales round a woody axis j heart-shaped fruits or 



