TRIASSIC PERIOD. 417 



3. Vertebrates. — (a.) Fishes. —Fig. 718, Catopterus gracilis Redfield (reduced 

 one half), from Middlefield, Ct.; also found in North Carolina and at Phoenixville, 

 Pa. ; 718 a, scale of same, natural size. There are also other species of Catopterus ; 

 also species of Ischypterus and of Turseodus Leidy (related to Belonostomus or Eu- 

 gnathus). In the last, the tail is not at all vertebrated. Radiolepis speciosus Emmons 

 is another Ganoid, from North Carolina and Pennsylvania. 



The best localities of fossil fishes are Sunderland, Mass. ; Middlefield Falls and 

 Southbury, Ct. ; Richmond Coal-beds, Va. ; Phoenixville, Pa. 



Amphibians. — Fig. 723, Anisopus gracilis Hk., reduced one third. Fig. 722, Anisopus 

 Deiceyaiius Hk., half natural size. Fig. 719, Macroptema divaricans Hk. (reduced to 

 one sixth). Portions of the skeleton of Amphibians have been detected by Leidy among 

 the fossils of Gwynned, Pa., twenty miles north of Philadelphia, find also among those 

 found at Phoenixville ; and Emmons has figured a portion of the head of a tine species 

 from North Carolina. 



(c.) Dinosaurs. — Figs. 721, 721 cp, tracks of fore and hind feet of Anomoepus scambus 

 Hk.; 729, tooth, reduced one-half, of Bathygnathus borealis Leidy, from a jaw found in 

 the rocks of Prince Edward's Island, referred to the Amphibians by Leidy, to the The- 

 codonts by Owen, and to the Dinosaurs by Cope. Fig. 724, Olozoum Moodii Hk., one 

 eighteenth natural size. Fig. 727, tooth, natural size, of the Clepsysaurus PennsyU 

 vanicus Lea, the edge sharp-denticulate, from North Carolina, and Phoenixville, Pa. 



(d.) Crocod'dians. — 726, one of the back set of teeth of Belodon priscus Leidy, from 

 North Carolina; 726 a, section of same; 728, one of the front set of teeth of B. Caro- 

 linensis Cope, from North Carolina, and Phoenixville, Pa.; B. Leaii Cope, from North 

 Carolina ; B. lepturus Cope, from Phoenixville. Also the Rhynchosaur (according to 

 Cope), Rhabdopelix longispinis Cope, from Phoenixville, formerly regarded as a Ptero- 

 saur. 



Coprolites are abundant in the shales of Phoenixville. 



(e.) Birds {?). — Fig. 725, Brontozoum giganteum Hk., reduced to one-sixth natural 

 size. Fig. 730, part of a slab of sandstone figured by Hitchcock, one-thirtieth natural 

 size: a, b, c, three kinds of bird-like tracks; a and c, of the genus Brontozoum Hk.; a, 

 a, same as b, but drawn larger, to show the articulations of the toes. Figs, d, e, two 

 kinds of Reptilian tracks, of the genus Anisopus Hk., d, Anisopus Deweyanus Hk. 

 Natural length of a, 4 inches; of b, 8 to 9 inches; of c, 3| inches; of d and e, 1 to 1| 

 inches. The best localities of tracks of birds and other animals are at Greenfield and 

 Turner's Falls, Mass. ; Portland, Conn. 



(f. ) Mammals. — Fig. 731, Dromatherium sylvestre Emmons, from North Carolina. 

 Owen says of the species that "this Triassic or Liassic Mammal would appear to find 

 its nearest living analogue in Myrmecobius, Fig. 732, p. 416; for each ramus of the 

 lower jaw contained ten small molars in a continuous series, one canine and three 

 conical incisors, — the latter being divided by short intervals." 



m. Disturbances. — Igneous action. — Trap rocks. 



Trap ridges and dikes accompany this formation on the Atlantic 

 border. The rocks constituting them are of igneous origin, and were 

 ejected in a melted state, through fissures in the earth's crust. It is 

 remarkable that these fractures should have taken place in great num- 

 bers just where the Triassic beds exist, and only sparingly east or west 

 of them ; and also that the igneous rock should be essentially the same 

 throughout the thousand miles from Nova Scotia to North Carolina. 

 The igneous and aqueous rocks are so associated that they necessarily 

 come into the same history. Mount Tom and Mount Holyoke, of 

 Massachusetts, are examples of these trap ridges ; also East Rock and 



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