TRIASSIC PERIOD. 409 



very large pith, abounding in starch, surrounded by one or more rings 

 •of wood, each the result of several years growth. 



Characteristic Species. 



Conifers. — The genus Voltzia contained cypress-like trees, having lax leaves, the 

 terminal often longer than the others ; and the f ruit-branchlet consisted of broad and 

 short leaves or scales. A species near V. heterqphylla Schimp. (Fig. 737) has been found 

 in the American rocks, at the Little Falls of the Passaic, in New Jersey. Several Fir 

 cones, six inches long, have been found at Phcenixville, Pa. ; and a small one from the 

 Massachusetts beds has been figured by Hitchcock. 



Cycads. — PterophyUum longifolium Braun, from North Carolina and Pennsylvania, 

 •characteristic of the Upper Trias in Europe, resembles much Fig. 739; P. graminioides 

 Emmons, Fig. 706, from North Carolina. Fig. 705, Podozamites lanceolatus Emmons, 

 from the same locality. 



Acroyens. — Fig. 707, Clathroptei-is rectiuscula Hk., from Easthampton, Mass., near 

 the middle of the Sandstone formation: in one specimen there were seventeen such 

 fronds radiating from one stem. Fig. 708, Pecopteris (Lepidopteris) Stuttgartensis 

 Brngt., a fern with the fruit, from the Richmond Coal-beds, found also in the Trias 

 of Europe. Fig. 709, Neuropteris (f) linnceifolia Bunbury, from Richmond. Other ferns 

 are the Acrostichites oblonyus Gopp., and Laccopteris falcata Emmons, both from North 

 Carolina. Equisetum Rogersii Schimp. occurs at Richmond, Va., and in Pennsylvania. 

 One or two Catamites have been found in North Carolina. 



The vegetation of the beds is' decidedly Triassic in character. Pecopteris Stuttgart- 

 ensis and PterophyUum longifolium are Upper Triassic in Europe ; Laccopteris falcata 

 closely resembles L. germinans Gopp., an Upper Triassic species; Neuropteris linncei- 

 folia is near N. pachyrachis Schimp., also Upper Triassic ; Clathroptcris and Voltzia are 

 Triassic or Jurassic. The prevalence of Cycads is decidedly Mesozoic, and not Per- 

 mian. Catamites and species of Neuropteris occur in the European Trias, as well as in 

 the Permian and Carboniferous. 



2. Animals. 



On the Atlantic Border, the Triassic rocks have afforded no traces 

 of Radiates, and but few of Mollusks. This singular fact is partly 

 accounted for through another, already stated, — that the beds are 

 either fresh-water or brackish-water deposits. 



On the Pacific Border, in California and Nevada, the beds have 

 afforded many marine fossils. Among them are species of the Paleo- 

 zoic genera Spirifer, Orthoceras, and Goniatites ; besides others that 

 are as strikingly Mesozoic, such as Lamellibranchs of the genera 

 Monotis, Myophoria, etc., and Ammonites of the genus Ceratites, etc. 

 (Figs. 710 A-D), and others. 



A foreign species of Triassic Myophoria is represented on page 426. 



The Devonian Goniatites were the earliest known representatives 

 of the Ammonite group of Cephalopods, the prominent characteristics 

 of the shells of which are that the siphuncle is dorsal, and the trans- 

 verse partitions are flexed at the margin so as to make there a series 

 of pocket-shaped cavities opening upward. Figs. 710 A, B are dif- 



