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Contents.
Page.
Letter of transmittal 9
Introduction 11
I. —Eagle Pass and Eocene Coal Fields of the Middle Rio Grande Region.
Definition of area 13
General physical features 13
Descriptive geology 15
Cretaceous 15
Rio Grande section 15
Lower Cretaceous (Comanche series) 16
Edwards limestone 16
Fort Worth limestone 16
Del Rio clays 17
Buda limestone 18
Upper Cretaceous 18
Dakota division (absent) 18
Eagle Ford formation 18
Austin chalk 19
Upson clays 20
Eagle Pass formation 21
San Miguel beds 21
Coal series 22
Escondido beds 26
Resum6 of characters and thickness of the Eagle Pass for-
mation 28
Reconnaissance from Cline, Uvalde County, to Eagle Pass 28
Reconnaissance from Eagle Pass to Carrizo Springs 30
Studies along Turkey Creek and the Nueces River, the Frio and Sabinal "rivers, Brackett and Uvalde quadrangles (eastern Kinney County and Uvalde County) 31
Anacacho formation 31
Eagle Pass formation in Brackett and Uvalde quadrangles 33
Variations in character of the formations in the different sections 34
Anacacho formation and Upson clays 34
Eagle Pass formation 35
Relation of the Cretaceous to the Eocene 35
Rio Grande section 35
Between Eagle Pass and Carrizo Springs 35
Along the Nueces River 36
Along the Frio River 36
Tertiary 37
Eocene 37
Rio Grande section 37
Reconnaissance between Eagle Pass and Carrizo Springs and southwest of Carrizo Springs 46
