ILLUSTRATIONS 
Page. 
Plate I. Map of the region of the Eagle Pass and Eocene coal fields of the 
Middle Rio Grande in Texas 13 
II. The Rio Grande, from Mexican side of the river opposite Eagle Pass. 26 
III. A, Cretaceous-Eocene contact on the Frio River, 2 miles below 
Engelmann's ranch, southern Uvalde County; B, Basal Eocene 
bluff on the Frio River 50 
IV. A, Lower Eocene sandstone on the Frio River; B, Artesian well, 
Dinman's jilace, near Carrizo Springs 52 
V. Bluff of Rio Grande at Eagle Pass, showing the upper plain (Uvalde 
formation level) and the wide silt terrace (Columbia formation 
level) 54 
VI. Map showing the topographic features of the San Carlos region and 
the localities described in this report 74 
VII. View of the Vieja Mountains looking south from Chispa 76 
VIII. View of the Vieja Mountains looking east from San Carlos 78 
IX. View of Gettysburg Peak from San Carlos 80 
X. Bracks Canyon, entrance to eastern end, San Carlos 82 
XI. Columnar sections 84 
Fio. 1. Map showing the general position of the Rio Grande coal fields 14 
, 2. Section of hill on east side of Elm Creek, 1 mile above bridge, at the 
crossing of the Del Rio and Eagle Pass road 23 
3. Section of the Eagle Pass artesian well 25 
4. Section of the Anacacho Mountains, Kinney County 32 
5. Weathering of the Carrizo sandstone at Chupadero ranch 53 
6. Sandstone and clays above coal horizon (Santo Tomas seam) at Santo 
Tomas 54 
7. Section of bluffs and terraces at Palafox 55 
8. Generalized diagram of Rio Grande terraces 55 
9. Sketch map showing coal mines and prospects near Eagle Pass 56 
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