CONTENTS. xv 



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Future of this Industry in the Eastern United States, 390. Fauna of the Car- 

 boniferous Age, 390 ; Invertebrates, 391 ; Insects, 397 ; Vertebrates (Fishes), 398 ; 

 Reptiles — Amphibians, 400: 1. Reptilian Footprints, 400; 2. Dendrerpeton, 

 401 ; 3. Archegosaurus, 402 ; 4. Eosaurus, 403 ; Some General Observations on 

 the Earliest Reptiles, 404. Some General Observations on the whole Palaeozoic, 

 405 ; Physical Changes, 405 ; Chemical Changes, 405 ; Progressive Change in 

 Organisms, 406 : General Comparison of the Fauna of Palaeozoic with that of 

 Neozoic Times, 407. General Picture of Pakcozoic Times, 407 ; Transition from 

 the Palaeozoic to the Mesozoic — Permian Period, 409 ; The Permian a Transition 

 Period, 409 ; Area in the United States, 413 ; General Character of Permian 

 Organisms, 413. 



CHAPTER IV. 

 Mesozoic Eka.— Age of Reptiles 414-497 



General Characteristics, 414 ; Subdivisions, 414. 



Section 1. Triassic Period, 415 ; Subdivisions, 515 ; Flora, 416; Animals, 416; 

 Fishes, 416; Reptiles, 417; Affinities of Triassic Reptiles, 419; Birds, 421; 

 Mammals, 421. Origin of Rock-Salt, 421 ; Age of Rock-Salt, 421 ; Mode of Oc- 

 currence, 422 ; Theory of Accumulation, 422. 



Section 2. Jurassic Period, 424 ; Origin of Oolitic Limestone, 424 ; Jurassic Coal- 

 Measures, 425 ; Dirt-Beds — Fossil Forest-Grounds, 425. Plants, 426 ; Animals, 

 428 ; Corals, 428 ; Brachiopods, 428 ; Lamellibranchs, 428 ; Cephalopods, 428 ; 

 Ammonites, 430 ; Belemnites, 432 ; Crustacea, 434 ; Insects, 435 ; Fishes, 436; 

 Reptiles, 437 ; Birds, 444 ; Origin of Birds, 448 ; Mammals, 448 ; Affinities of 

 the First Mammals, 448 ; Origin of Mammals, 449. 



Section 3. Jura-Trias in America, 450; Distribution of Strata, 451. Life-System, 

 452 ; Connecticut River Valley Sandstone — The Strata, 452 ; Reptilian Tracks, 

 454 ; Supposed Bird-Tracks, 454 ; Richmond and North Carolina Coal-Ficlds,456 ; 

 Other Patches, 458 ; Interior Plains and Pacific Slope, 458 ; Recent Discoveries, 

 460; Atlantosaur Beds, 460; Dinosaurs, 460 ; Ichthyosaurs, 466; Birds, 466; 

 Mammals, 467 ; Physical Geography of the American Continent during the Jura- 

 Trias Period, 467 ; Disturbances which closed the Period, 468. 



Section 4. Cretaceous Period, 469 ; Rock-System — Area in America, 469 ; Physi- 

 cal Geography, 469; Rocks, 470; Chalk, 470; Origin of Chalk, 472; Extent of 

 Chalk Seas of Cretaceous Times in Europe, 473 ; Subdivisions of the Cretaceous, 

 474. Life-System : Plants, 474 ; Origin of Dicotyls, 477 ; Potomac Group, 477. 

 Animals, 477 ; Protozoa, 477; Echinoderms, 478 ; Mollusks, 478 ; Vertebrates 

 —Fishes, 482 ; Reptiles, 484 ; Birds, 488 ; Mammals, 492. Continuity of the 

 Chalk, 492 ; General Observations on, the Mesozoic, 494 ; Disturbance which 

 closed the Mesozoic, 494 ; Transition Period — Laramie, 495 ; How formed, 496 ; 

 Plants of, 497 ; Coal of, 498 ; Animals, 498 ; Reptiles, 499 ; Mammals, 500. 



CHAPTER V. 



Cenozoic Era. — Age of Mammals 497-586 



General Characteristics of the Cenozoic Era, 501 ; Divisions, 501. 

 Section 1. Tertiary Period. — Subdivisions, 502 ; Rock-System — Area in the 

 United States, 503 ; Physical Geography, 504 ; Character of the Rocks, 506 ; 

 Coal, 506; Life- System, 506; General Remarks, 506 ; Plants, 507; Diatoms, 

 510; Origin of Infusorial Earths, 511; Animals, 511; Nummulitic Limestone, 

 512; Insects, 514; Fishes, 518 ; Reptiles, 519; Birds, 520; Mammals — General 



B 



