TRIASSIC PERIOD. 417 



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

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

 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 speciusus 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. 



(b.) Reptiles. — (1.) Amphibians. — Fig. 723, Ariisopus gracilis Hk., reduced one 

 third. Fig. 722, Anisopus Deiueyanus Hk., half natural size. Fig. 719, Macropterna 

 divaricans Hk. (reduced to one sixth). Fig. 724, Otozoum Moodii Hk., one eighteenth 

 natural size. Portions of the skeleton of Labyrinlhodont Amphibians have been de- 

 tected by Leidy among the fossils of Gwynned, Pa., twenty miles north of Philadel- 

 phia, and also among those found at Phoenixville ; and Emmons has figured a portion 

 of the head of a fine species from North Carolina. 



(c.) Dinosaurs. — Figs. 721, 721 a, tracks of fore and hind feet of Anomaepus scam- 

 bus Hk. ; 725, 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 

 Thecodonts by Owen, and to the Dinosaurs by Cope. 



(d.) Lacertians. — Fig. 727, tooth, natural size, of the Clepsysaurus Pennsylvanicus 

 Lea., the edge sharp-denticulate, from North Carolina, and Phoenixville, Pa. ; 726, one of 

 the back set of teeth of Belodon priscus Leidy, from North Carolina ; 726 «, section 

 of same ; 728, one of the front set of teeth of B. Carolinensis Cope, from North Caro- 

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

 from Phoenixville. Also the Rhynchosaur (according to Cope), Rhabdopelix longispinis 

 Cope, from Phoenixville, formerly regarded as a Pterosaur. 



Coprolites are abundant in the shales of Phoenixville. 



(e.) Birds (?). — Fig. 729, 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 1J 

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

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



(_/*. ) 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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