4. Topographical Map of Linton, Ohio, Region 16 5. Fossil Tree Trunk in Position 21 6. Generalized Amphibian Skull 23 7. Alimentary Canal of a Carboniferous Salamander 26 8. Vertebræ and Ribs of Coal Measures Amphibia 28 9. Ventral Scutellæ of Micrerpeton 30 10. Horny Armor of Hylonomus 31 11. The Skulls of two Microsaurians: A, Eoserpeton tenuicorne; B, Ceraterpeton galvani 33 12. Devonian Footprint 37 13. Restoration of Micrerpeton 53 14. Mazon Creek Amphibia: A, Eumicrerpeton parvum; B, Amphibamus thoracatus 59 14_a_. Skeleton of Mazonerpeton longicaudatum 62 14_b_. Skeleton of Mazonerpeton costatum 64 15. A. Impression of Erierpeton branchialis 65 B. Eumicrerpeton parvum 65 C. Larger Specimen of Eumicrerpeton parvum 65 D. Skeleton of Erpetobrachium mazonensis 65 E. Rib of Mazonerpeton costatum 65 15_a_. Type Material of Sparodus 66 16. Obverse of Cocytinus gyrinoides 68 16_a_. Nearly Complete Specimen of Cocytinus gyrinoides 69 17. Pelion lyelli, supposed ancestral Salientian 74 18. Skeletal Elements of Smilerpeton aciedentatum 82 19. Skull and Skeleton of Tuditanus punctulatus 87 20. Skull and Skeleton of Tuditanus longipes 90 21. Skeleton of Tuditanus walcotti: A, Body; B, Leg 94