Part IIT, Sect. i.§ 1.] | TRIASSIC, 761 
Acrostichites, Clathropteris, Crematopteris, Sagenopteris. The earliest 
undoubted horse-tail reeds occur in this system. Here they are 
represented by the two genera Hgwisetwm (Fig. 359) and Schizo- 
newra. ‘The latter genus died out in the Jurassic period, but the 
former is still represented by twenty-five living species. The conifers 
are represented by Voltzia, the cypress-like or spruce-like twigs of 
which are specially characteristic organisms of the Trias (Fig. 360), 
and by Albertia. But the most distinctive feature in the oie of 
the earlier Mesozoic ages was the great development of cycadaceous 
vegetation. ‘The most abundant genus is Pterophyllum ; others are 
Zamites, Pterozamites, Podozamites, Otozamites. So typical are these 

Fic. 360.—VoLTZIA HETEROPHYLLA (Brongn.), 
plants that the Mesozoic formations have been classed as belonging 
to the “Age of Cycads.” 
The fauna is exceedingly scanty in the red sandy and marly 
strata of the central European Trias, and comparatively poor in forms, 
though often abundant in individuals in the calcareous zones of the 
same region. From the Alpine development a much more varied 
suite of organisms has been disinterred. Some of the Alpine lime- 
stones are full of foraminifera. Corals abound in some localities in 
the same rocks, Hchinoderms are plentiful among the limestones, 
particularly ermoid-stems, of which these rocks are in some cases 
almost wholly composed. One of the most characteristic fossils of 
