25

In a recent paper the author endeavored to present au outline of the physiographic features of the Texas region, as shown on a new map therewith, and to define its salient primary natural subdivisions, as a basis for more detailed discussion and differentiation of the various phenomena. The limits and plan of that paper forbade extended discussion or description of specific local features. The present paper will be devoted to a minute description of one of the provinces of the greater region as outlined in the paper mentioned. Before beginning this description, however, it will be well to give a brief résumé of the region as a whole.

The Greater Texas region includes practically all the country east of the Rio Grande south of the northern boundary of New Mexico. The region thus defined is not a physical unit, but rather an area which includes a peculiar group of physiographic units, composed of mountains and plains belonging to the four greater natural provinces of the United States, to wit: the Cordilleran region, the Great Plains region, the Appalachian region, and the Atlantic Coastal Plain. The characteristic features of these regions as they extend into the State present local modifications. There are also extensive stretches of country in the central portion of the State which have no counterpart elsewhere.

Before the individual physiographic features of the Greater Texas region are described the area, relations, and subdivisions of the State will be noticed.

The area of the State of Texas is 265,780 square miles, or about one-twelfth that of the entire United States. Its magnitude will be better appreciated when it is remembered that to the combined area of the New England States, New York, New Jersey, Pennsylvania, Delaware, Maryland, and the District of Columbia the areas of Ohio and Kentucky must be added to equal it. Its extent is about that of "

Physical geography of the Texas region: Topographic Atlas U. S., folio 3, U. S. Geol. Survey, 1900.