G Gaptank formation: 35, 41 gastroliths: 14 Gastropoda: 56, 59 gastropods: 26, 27, 29, 30, 56, 59, 60 Cretaceous: 59, 62 morphology: 60 ornamentation: 59 Pennsylvanian: 61, 62 Tertiary: 59, 63, 64 generic name: 21-22 genus: 21-22 geologic— column: 33 history: 33 map, definition: 40 map of Texas: 38-39 time: 34 time scale: frontispiece, 33 geology of Texas: 37-43 Germany: 5, 100 _Gingko_: 47, 48 _Girtyocoelia_: 50 Glasscock County: 42 Glass Mountains: 11, 12, 35, 41, 42 glauconite: 11 _Globigerina_: 49 Glossary: 111-114 _Glycymeris_: 74 _Glyptodon_: 101, 102 glyptodont: 101, 102 goats: 106 goniatites: 75, 76 Grand Prairie: 36, 37 Graptolithina: 84, 86 graptolites: 27, 30, 40, 84, 86 of Marathon uplift: 40, 86 Graptozoa. _See_ graptolites. _graysonana, Gryphaea_: 69 Great Flood: 3 ground sloths: 7, 101, 102 _Gryphaea graysonana_: 69 _washitaensis_: 69 Guadalupe Mountains, Peak: 35 Gulf Coast: 32 Gulf Coastal Plain of Texas: 35, 36, 37, 42, 43, 106 Gulf of Mexico: 37 Gulf series of Cretaceous: 34. _See also_ Upper Cretaceous. _Gyrodes_: 62 H hagfish: 87 hammer, geologist’s: 17, 18 _Hamulus_: 78 hand lens: 17, 18 hard parts, animal—calcareous, chitinous, phosphatic, siliceous remains: 10 Hardin-Simmons University: 27 heart urchins: 82, 83 _Heliospongia_: 50 hematite: 11 _Hemiaster_: 85 Hemichordata: 84 Henderson County Junior College: 27 Herodotus: 3 _Heterostegina_: 32 _Heteralosia hystricula_: 12, 13 “het” zone: 32 Hexacoralla: 51 High Plains: 35, 36, 37, 42, 43, 89, 95, 106 hippopotamuses: 106 _Holaster_: 85 _Holectypus_: 85 Holothuroidea: 82 holothuroids: 84 sclerites: 83 _Homo sapiens_: 22 “horn corals”: 49, 51, 52 horses: 103, 104 teeth: 104 Howard County Junior College: 27 Hudspeth County: 35, 41, 42 Hueco Mountains: 41 Hughes, Jack T.: 1 hydroids: 49 Hydrozoa: 49, 84 _Hyracotherium_: 103, 104 _hystricula, Heteralosia_: 12, 13 I ichthyosaurs: 91, 93, 95 _Ichthyosaurus_: 91, 93 identification keys, fossil: 26-30 use of: 23-27 igneous rocks: 5, 19 Inarticulata: 54, 56 _Inoceramus_: 69 insects: 7, 78, 79 in amber: 7 iron, replacement by: 11 Italy: 3 J Jack County: 20 jellyfish: 5, 49 Jurassic— derivation and pronunciation: 34 fossils: 42 birds: 100 dinosaurs: 90, 91, 95, 97, 98, 99 _Gingko_: 48 of Hudspeth County and/or Malone Mountain: 41 _Juresania_: 58 K keys. _See_ identification keys. Kilgore College: 27 _Kingena wacoensis_: 56