Physical Geography of the Texas Region.
In this paper the author has endeavored to pre sent a scientific outline of the physiographic fea tures of the Texas region, as shown on a new map herewith (Sheet XI), and to define its salient generic natural subdivisions, as a basis for more detailed discussion and differentiation of the vari ous phenomena in the future. The limits and plan of the paper forbid extended discussion or description of specific local features.
Data on which map is based. —The map, on a scale of 25 miles to the inch, is intended to show, so far as can be shown on that scale, all that is known concerning the physical geography of the region. Many of the minor details of culture have been intentionally omitted, in order that the physiographic features may stand forth more clearly; only the political boundaries, the railroads, and the names of States, counties, and county seats are given, except a few important towns here and there, which are conspicuous landmarks. In com piling the map the author has drawn, for data, from every possible source, including all known surveys and reconnaissances. The data may be classified under six distinct heads:
1. Detailed topographic surveys by the United States Geological Survey and the special land survey of the Indian Territory.
2. The survey of the coast of the Gulf of Mexico and triangulation of the lower Rio Grande border by the United States Coast and Geodetic Survey. 3. The surveys of the various boundary com missions.
4. The drainage of the eastern half of Texas as given on Pressler and Langermann's map of Texas, compiled from the Texas land surveys, 1877, and the United States Land Office maps of Indian Territory and New Mexico.
5. Reconnaissance surveys made by various United States exploring and railway expeditions.
6. The individual reconnaissances and observa tions of the writer.
Future work will no doubt supply details for many of the unsurveyed parts of the region, espe cially those embracing the unsurve} Ted portion of eastern New Mexico and the portion of Texas included in the great bend of the Rio Grande. The author feels confident, however, that the map presents as close an approximation to a correct representation of the geography of the region as it is possible to attain with our present incom plete knowledge.
The portions of the map covered by the above data are shown in fig. 12, Sheet I, Special Illustra tions.
Greater Texas Region.
The American pioneers of the original Republic of Texas defined its limits as that country lying between the Rio Grande and the Arkansas to their headwaters, extending east to the one hundredth meridian, as laid down on Mellish's map, north of Red River, and east to the Sabine south of the latter stream. The boundaries of the Republic of Texas as specified in an act of the Texas Con gress approved by President Houston December 19, 1886, were as follows:
Beginning at the mouth of the Sabine River and running west along the Gulf of Mexico, three leagues from land, to the mouth of the Rio Grande, thence up the principal stream of said river to its source, thence due north to the forty-second degree of north latitude, thence along the boundary line as defined in the treaty between the United States and Spain, to the beginning.
The northern and eastern boundaries of the Republic of Texas above mentioned, as defined in the treaty betAveen the United States and Spain, were as follows:
The boundary line between the two countries, west of the Mississippi, shall begin on the Gulph of Mexico, at the mouth of the river Sabine, in the sea, continuing north, along the Avestern bank of that river, to the thirty-second degree of latitude; thence by a line due north to the degree of latitude where it strikes the Rio Roxo of Nachitoches or Red River; then following the course of the Rio Roxo to the degree of longitude 100° west from London, or about 23° west of Wash ington; then crossing the said Rio Roxo and running thence, by a line due north, to the River Arkansas; thence, following the course of the southern bank of the Arkansas, to its source in latitude 42° north.
There was then little accurate knowledge of the sources of the rivers mentioned in these treaties or of the geography of the country with which they dealt. The boundaries of the Republic of Texas included a large section of our country — Texas, southern Kansas, Oklahoma, eastern New Mexico, and a portion of Indian Territory — which, by reason of its natural relations, may be appropri ately termed the Greater Texas region. The political boundaries have since been restricted to the present limits of the State, and it is this restricted area which will chiefly be considered in this paper, although it will often be necessary to extend descriptions of natural features into adja cent and related regions.
The Greater Texas region includes practically all the country east of the Rio Grande south of the northern boundary of New Mexico. The great Mesa de Maya, which extends eastward alono- the Colorado-New Mexico boundary from the one hundred and fifth meridian near Trinidad nearly to the northwest corner of Texas, forms a natural physiographic banier dividing the Avestern part of the Great Plains into northern and south ern portions. From the eastern limit of this mesa eastward the Purgatory and the Arkansas below the mouth of the Purgatory make the northern boundary as far east as the one hundredth merid ian. Thence the northern boundary is made by the Breaks of the Plains, running eastward and northeastward in southern and eastern Kansas, until they intercept the southern border of the glaciated plains in northeast Kansas.
The eastern border of the Greater Texas region is irregular and may be considered as the western border of the Ozark Plateau of eastern Missouri and northeastern Indian Territory as far south as Arkansas River, where the Ouachita Mountains are encountered. The latter form a lon^tongutv like projection which stretches westward^^^^^H into the Greater Texas region. Suuf.liß of the Ouachita Mountains there are n<>l physiographic features to mark the <\-isl -M crn border of the area, the Coastal Plui nl continuing east indefinitely. For I hcH line of limitation we assume the westemß boundaries of Arkansas and Louisi.-m.-i.H On the south the Gulf of Mexico and (11< I Rio Grande are the natural boundaries.^^^^^B
The Greater Texas region thus defined is not a physical unit, but rather an area which includes a peculiar group of physi ographic 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 extensions of these features 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 indi vidual physiographic features of the Greater Texas region are described the area, relations, and subdivisions of the State will be noticed.
The State of Texas.
Area and Relations.
The area of the State of Texas is 265,780 square miles, or about one-tAvelfth 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, Mary land, and the District of Columbia, the areas of Ohio and Kentucky must be added to equal it. Its extent is about that of France. Its length and breadth are nearly the same. The former is 760 miles, and the latter, along the thirty-second parallel, is about 740 miles. By rail these distances are 900 miles, or the same as from New York to Savannah, Atlanta, Chattanooga, Evansville (Indiana), Chicago, or Labrador. Its length is one-half that of our country from north to south. Its width is more than one-half the southern border of the United States between the
Atlantic and the Pacific. Tins width is equal to one-third the distance across the widest portion of the country, from Cape Hatteras to Cape Mendo cino.
In respect to location and natural conditions Texas does not fit exactly into any one of the ordinary classifications of States. It is south ern — Florida excepted, the most southern of all the States in geographic position. It is central, for it is one of the great tier that exactly forms the central strip of the Union. It is a Gulf State, and has one-fourth the shore line of the Gulf of Mexico. It is a western State, large areas of both the Great Plains and the Cordilleran regions being included in it, while its far western corner is nearer the Pacific than the Atlantic and has the climatic features of the former rather than of the latter. Not only do its parts present the geo graphic features of the larger divisions of the United States already mentioned, but there are areas typical of the adjacent Republic of Mexico, such as the northern end of the Tierra Caliente at the mouth of the Rio Grande. Hence it may be said that Texas is both southern, central, and western in relative position and interests.
Subdivisions of the State.
Neither the State of Texas nor the adjacent territories within the Greater Texas region have well-defined or officially recognized subdivisions. In Texas vague subdivisional terms have grown into popular use, but these have not been recorded or defined. Personal observation of this local usa^e shows that it includes two classes of terms: first, terms of direction, vaguely applied without definite reference to natural subdivisions; second, names based on specific natural features and applied to local districts colloquially called " countries."
Fig. I.—Provinces and minor subdivisions of the Greater Texas region
The directional names in common use in Texas are as follows: East Texas, South Avest Texas, Cen tral Texas, Northwest Texas, North Texas, and West Texas. The bounds of the areas which these terms are intended to designate have never been defined, and it is doubtful whether they are well formulated in the public mind. They were not originally used with reference to the geographic center of the State, but were and still are employed with reference to the early American centers of population in the extreme eastern part. Thus all the areas to which these names are applied lie east of the central meridian of the State. Southwest Texas, for instance, according to this older nomen clature, embraces the country between the Bal cones scarp line, the Rio Grande, and the coast. This region, relative to the geographic center of the State, is really southern Texas, as it will be called in this folio. Central Texas was the region traversed by the Houston and Texas Central Rail way, and included a country (the east half of the East-Central Province of nomenclature) more than 100 miles east of the true Central Province as defined in this paper. North Texas was the tier
of black-land counties adjacent to Red River, and included only the eastern third of the northern border. Northwest Texas was almost the exact geographic center of the State. The term West Texas was applied to the region immediately beyond the westwardly migrating line of frontier settlement.
No set of directional terms coincides exactly with the natural subdivisions of the State; never theless, such terms are convenient and often unavoidable in description. The use made of them in this folio, how Tever, is quite different from that noticed in the last paragraph, and results from a new classification of the region into provinces, based on physical characters and relations.
The parts of the Greater Texas region which, by reason of natural features — characteristics of soil, climate, geologic structure, drainage, under ground water conditions, and environment for human culture — constitute geographic units for discussion, or provinces, are six in number (see fig. 1). These provinces may be briefly outlined as follows:
1. The -Eastern Province. —This consists of the northern half of the Texas Coastal Plain, and includes the forest country east of the Black Prai rie and north of the thirtieth parallel, which corresponds approximately to the latitude of Austin. It represents the continuation into Texas from Arkansas and Louisiana of the Atlantic timber belt of the interior portion of the southern Coastal Plain. In Texas it embraces 33,000 square miles.
2. The Southern Province. —This is the southern half of the Coastal Plain in Texas and the modi fied southern extension of the Eastern Province. It includes the area between the thirtieth parallel on the north, the Balcones scarp line on the west,
and the Uio Grande on the south as far west as Del Kio. It contains a diverse group of countries, such as the Coast Prairie, the Fayette Prairie, the Carrizo country (an attenuated southwestern extension of the Atlantic timber belt), the Coraal country (the southern con tinuation of the Black Prairie), and the liio Grande embayment. Its area aggre gates 52,000 square miles.
3. The East-Centred Province. —This includes the portion of Texas north of the Colorado between the Eastern Prov ince and the Central Province proper, and the portion of southern Indian Ter ritory south of the Ouachita Mountains and east of the ninety-seventh meridian. It includes the Black and Grand prairies and the two belts of timber known as the Western and Eastern Cross Timbers. Its area is about 31,000 square miles.
4. Hie Central Province. —This is a vast area of diversified prairie plains in
southern Kansas, Oklahoma, Indian Territory, and Texas, lying between the Plateau of the Plains and the western border of the Ozark Plateau and the East-Central Province. It is the Central De nuded region of the writer's previous papers, and consists of a number of diverse prairie features occurring in more or less regular north-south belts succeeding one another to the west, including those established upon the Red Beds, the Carboniferous, and the older Paleozoic rocks, each of which will be described under its appropriate head. The area of its southern portion which lies in Texas is 37,000 square miles.
5. The Great Plains Province. —This includes the Great Plains proper, which extend eastward from the Rocky Mountain front to the prairie plains of the Central Province and southward to the Southern Province.
sa. The Plateau Subprovince of the Great Plains. —This is the modified southern extension of the Great Plains region of the United States. In Texas it is an extensive oblong plateau south of Canadian River, comprising the Llano Estacado and the Edwards Plateau — 60,000 square miles. The Stockton Plateau, between the Pecos and the