vaughan.] LITERATURE. 67 
special examination of particular localities. All that can be done is to 
indicate places and give such data as may be collected under the con- 
ditions of the work, as a guide for future detailed examinations. 
LITERATURE. 
The following annotated bibliography may be of assistance to those 
interested in the history of geologic investigation in this region: 
1857. Schott (Arthur). Substance of the sketch of the geology of the Lower Rio 
Bravo del Norte: Reports of the Mexican Boundary Survey, Vol. I, Pt. II, pp. 
28-48. 
This article is a preliminary reconnaissance and contains no detailed 
stratigraphic work. Schott's observations, taken in connection with 
the determination of the fossils by Conrad, showed the existence of 
large areas of Cretaceous rocks in the region covered by his reconnais- 
sance, i. e., from the mouth of the Pecos River to a point between 
Eagle Pass and Laredo. After personally studying the region, some 
of the beds in Schott's description will be recognized as those which 
have since been specifically named. Between the Pecos and Del Rio 
Schott observed the peculiar buttes formed from the Exogyra arietina 
(Del Rio) clays. He made observations on the coal-bearing beds in the 
vicinity of Eagle Pass, and noted outcrops of coal* near Palafox. 
1882. Adams (W. H.). Coals in Mexico, Santa Rosa district: Am. Inst. Mining 
Engineers, Vol. X, pp. 270-273. 
The paper of Mr. Adams is one of the first and best descriptions 
j of the Lower Rio Grande coal fields as a whole, although he made 
• erroneous deductions concerning their exact age. From lithological 
i characters he referred the Santa Rosa coal to the Trias, and for similar 
reasons he referred the Eagle Pass coal to the Permian. 
1884. Loughridge (R. H.) . Report on the cotton production ot the State of Texas: 
Tenth Census of the United States, Vol. V. 
This publication contains several notes on the general geology of the 
region of the Rio Grande Plain. 
1884. Cope (E. D.) . A note on the geology of the vicinity of Laredo: Proc. Am. 
Philos.Soc, Vol. XXI, p. 615. 
Cope considered the lignite-bearing beds (the Santo Tomas coals) 
above Laredo as Laramie, and stated that they arc immediately over- 
lain by the Claiborne. 
1885. McGee (W J). Geological map of the United States: Fifth Ann. Rept.U. S. 
Geol. Survey. 
McGee represents the northern boundary of the Eocene as reaching 
almost to the twenty-ninth parallel on the Rio Grande, and the southern 
boundary as crossing that river south of the twenty-eighth parallel and 
a little east of the ninety-ninth meridian. 
1886. Hitchcock (C. H.). Geological map of the United States: Trans. Am. Inst. 
Mining Engineers, Vol. XV. 
