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 fruit-branchlet consisted of broad and 

 short leaves or scales. A species near V. heterophylla 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 Phoenixville, Pa.; and a small one from the 

 Massachusetts beds has been figured by Hitchcock. 



Cycads. — Pterophyllum longifollum 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. 



Acrogens. — Fig. 707, Clathropteris 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 bullata? (Fontaine), from the 

 Richmond Coal-beds. Fig. 709, Neuropteris linnazifolia Banbury, from Richmond; 

 Macrotceniopteris grandifulia, abundant, ibid. Other ferns are the Acrostichites oblongus 

 Gopp., and Laccopteris falcata Emmons, both from North Carolina. Equisetum Rog- 

 ersii Schimp, occurs at Richmond, Va., and in Pennsylvania. One or two Catamites 

 have been found in North Carolina. 



The vegetation of the Richmond beds is, according to Rogers (and also Fontaine), 

 more Jurassic than Triassic; while that of the more eastern Petersburg area is referred 

 b} r Fontaine to the Wealden. These include Conifers near Araucarites curvifulius Ett., 

 and the Cycad Pterophyllum Buchianum Ett., in great abundance, both Wealden species 

 in Europe. Pterophyllum longifollum is Upper Triassic in Europe; Neuropteris linncei- 

 folia is near N.pachyrachls Schimp., also Upper Triassic; Clathropteris and Voltzia are 

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



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 

 MonotiSy 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- 



