Recoed of Geology of Texas, 1887-1896. 
163 
Hill^ Robert T. 
Tertiary Basin of the Lower 'Bio (Grande. The Age of the Strata at Marble 
Falls and Shinbone Ridge. Aeolian Deposits of Eddy county, New Mexico. 
Possible Uses of Lignite. 
Part III of the Final Reports of the Artesian and IJnderflow 
“It lis impossible, owing to (the softness and lack of good exposures, to 
measure by surface sections the thickness of the Upper Gretaceous beds in 
Central Texas. An artesian well at Thorndale, however, penetrated 2000 
feet of the Glauconitic beds and Exogyra ponderosa marls.’^ 
The existence of Carboniferous rocks at (Shinbone ridge, as previously 
announced, is verified by the determination of fossils such as Zaprentis, 
Productus and other typical Carboniferous species. 
234. 
Preliminary Notes on the Topography and Geology of Northern 
Mexico and Sonthwest Texas, and New Mexico. 
Amer. Geologist, Vol. YIII, pp. 133-141; 2 cuts. Minneapo- 
lis, Sept., 1891. 
Contents : Geograiphic Extent of the Basin Region. The Mountains. 
The Plain. The Lomas. The Conglomerate Terrace. Geologic Structure 
of the Region. The Main Mass of Mountain or Sierra Grande. The Sierra 
Chiquita or Hog Backs. The Lomitos or Foot Hills. The Formation of 
the Plain. The Valley Conglomerate or Terraces. The Basaltic or Vol- 
canic Mesas. 
“The topographic and geologic features of northern Mexico, and the 
Trans-Pecos region of Texas and New Mexico have been for several years 
a subject of profound initeresit to the writer, who, notwithstanding much 
study, involving thousands of miles of travel, still feels that he can con- 
tribute only a few data concerning this vast region, and that the main 
facts and details of its structure are still unraveled, especially those 
relating to 'orographic and igneous geology, and he presents the aceompany- 
ing description of a small but typical portion of the area, with the hope 
that it may be of some assistance to those who are more conipetent to dis- 
cuss as a whole the grander orographic features of our continent.” P.- 
133. 
235. 
On the Occurrence of Artesian and other Underground Waters 
in Texas, Eastern New Mexico, and Indian Territory, west of the 
Ninety-seventh Meridian. 
Investigations', pp. 41-166, with nnmerons maps and illustrations. 
Senate Ex. Document 41, Pt. 3, 52d Cong., Ist Sess. Washing- 
ton, May, 1892. 
Contents. — Introduction : Letter to Chief Geologist. I. The Occur- 
rence and availability of underground water: Influence of Topography 
upoji 'distribLition of underground water; Water conditions most favor- 
able in later (newer rock sheets). II. General Outline of the Texas-New 
