Vlll CONTENTS. 



ACCOMPANYING PAPERS. 



PRELIMINARY REPORT ON THE GEOLOGY OF THE GULF TERTIARY OF TEXAS, BT R. A. F. 



PENROSE, JR. 



Introduction 5 



Descriptive Geology — 



Geography and Topography 7 



Stratigraphy 13 



Basal, or Wills Point clays^ 19 



Soils of the Basal clay region 21 



The Timber Belt, or Sabine River beds 22 



Brazos River section . . 25 



Colorado River section 28 



Houston County 34 



Marion and Cass counties 34 



Henderson County 36 



Timber Belt soils . 36 



Rio Grande section 38 



The Fayette beds 41 



Colorado River section 52 



Brazos River section ... 54 



Rio Grande section 56 



Soils of the Fayette beds 58 



Post-Tertiary deposits 58 



Upland gravel 59 



River silt... 60 



Coast clays ' 63 



Coast clay soils 64 



Economic Geology — 



Iron ores of East Texas 65 



Brown laminated ores 66 



Origin of brown laminated ores , 12 



Nodular or geode ores 76 



Origin of the nodular or geode ores 79 



Conglomerate ores * 81 



Analyses of ores 83 



Benches 84 



Building stones 86 



Sandstones and claystones 86 



Limestones 89 



Clays 89 



Glass sands 90 



time 90 



Marls 90 



Analyses . 94 



Lignites 94 



San Tomas coal mine 96 



Uses of lignite 97 



Analyses of lignite 98 



Mineral springs 98 



Oils 100 



Salt 101 



A BRIEF DESCRIPTION OF THE CRETACEOUS ROCKS OF TEXAS AND THEIR ECONOMIC USES, BY 



ROBT. T. HILL. 



Synopsis . 105 



Introduction 105 



Upper, or Black Prairie series 107 



Geologic structure of the Black Prairie region 109 



Lower Cross Timber sands 110 



Eagle Ford clay shales . . Ill 



White Rock, or Austin-Dallas chalk 112 



Exogyra Ponderosa marls 114 



Upper arenaceous, or glauconitic series 116 



