164 
Transactions Texas Academy of Science. 
Hill^ Egbert T. 
Mexican region : The eastward division of the coastward incline ; The Moun- 
tain systems; iKeninantal plains of the Tlano Estacado type; The plateau 
region; The basin plains of the Great Basin and Mexican Plateau region. 
III. Artesian 'Conditions and strueture of the eastern division of the coast- 
w-ard incline: The coastal prairie; The Washington or Fayette prairies; 
The East Texas forest region; The plateau gravel; The river terraces; The 
'Gretaceous prairies, including the cross-timber regions; The Main Black 
Prairie region; The northern division; The Austin-Dallas chalk. The Eagle 
Ford prairies, the Lower Gross Timbers, Geological substructure of the 
Black Prairies. The Grand Prairie region, including the Upper Gross 
Timbers— general outline and comparison with the Black Prairies: The 
Indian Territory division ; The Gentral or Fort Worth division ; The South- 
ern or Edwards Plateau division; The Stockton division; The altitudes of 
the Grand Prairie. Geological Structure of the Gretaceous Grand Prai- 
rie: 'Tile Trinity division; The Trinity or Upper Gross Timber sands; 
The Glen Pose or Alternating beds ; The Paluxy sands. The Gomanche 
Peak division or impervious beds; The Gryphaea ro'ck and Walnut clays; 
The iGomanche Peak chalk; The Gap'rina limestone; The Washita division. 
Topographic Expression of the Gomanche series : Water conditions of the 
Black and Grand prairies; The rivers .of the Grand Prairie; The Mammoth 
Springs of the San Antonio system, or natural .artesian 'wells; .The artesian 
waters .of the Black and Grand prairies; Availability of the water sheets 
of the Black and Grand Prairies; The water-bearing strata; The availabil- 
ity of the water-bearing sheets; The DailasPottsboTO Group or wells of 
the Lower Gross Timber flow; Extent and limitations of the area. Wells 
of the d^'ort Worth- Waco system: The shallower wells of the Paluxy flow; 
The deeper wells of the Trinity flow (Fort Worth-Waco) ; Bevelopment 
at Fort W'Ortli and Waco; The wells of the Glen Pose Group; Five hun- 
dred-foot wells of the Morgan Group; One thousand-foot wells of the Fort 
Worth-MoG-regor Group; Deep wells of the Waeo-Dallas Group; Artesian 
failures in Grand and Black Prairie regions; Gonelusions, etc., of artesian 
conditions in Grand and Black Prairie Pegions; Artesian conditions . south 
.of the .Golorado. IV. Water .conditions of the Pio Grande embayment. 
V. The Wiater conditions .of the central denuded region. VI. The Ped 
Beds or Goncho- Abilene country: Extent and conditions of the Ped Beds 
country; The Texas-Oklahoma division; The Pecos-Ganadian division. 
VIT. Water conditions of the Llano Estacado region: Extent and struct- 
ure; The great water-bearing cap-sheet, or Llano Forniation; Artesia.n 
possibilities of the Llano Estacado. VIII. Water conditions of the Trans- 
Pecos Basin region. IX.. Water coiiditions of the mountain region: The 
Baton-Las Vegas or plateau region; The Malpais .or volcanic regions of New 
Mexico. X. Water conditions, .of Indian Territory, including Oklahoma: 
Water conditions .of the hard limestone regions and other exceptional areas; 
SjDrings .of the Washita and Arbuckle .hlountains. 
“The region covered is so vast and embraces so. many diverse conditions 
influencing the water supply that I .have been able only to treat it most 
briefly. I feel, however, that in the .accompanying pages I have at least 
outlined the underlying principles of the water supply and pointed out their 
availability. 
“The region assigned the writer for investigation comprised Indian Ter- 
