GENERAL SURVEY OF TEXAS WOODLANDS. 7 



Plateau and the Cordilleran Mountains. The former occupies the south- 

 eastern portion and is separated from the Edwards Plateau only by the 

 canyon of the Pecos River. The Cordilleran Mountains are an exten- 

 sion into Texas of the Rocky Mountain system. 



The Plateau Province lies between the Central Basin and the Cor- 

 dilleran Mountains. Two divisions may be recognized, the Staked 

 Plains or Llano Estacado, and the Edwards Plateau. The Staked 

 Plains occupy the northern portion of the Plateau Province and are 

 level, treeless, grass covered plains. That portion lying north of the 

 Canadian River is commonly known as the Panhandle. The southern 

 part of the Plateau Province is represented by the Edwards Plateau, a 

 region which, with the Stockton Plateau, owes its existence to a fault 

 or crack and a bodily uplift from the surrounding country. 



The fourth of these arbitrary provinces is the Coastal Pla^n, or sea- 

 ward sloping area bordering the Gulf, which consists of overlapping 

 rock sheets deposited on the sea bottom in consecutive periods from 

 Cretaceous to Recent times. The Cretaceous formation consists of an 

 older or lower and a newer or upper series. The lower Cretaceous series 

 covers a vast area in Texas, including the Grand Prairie region and the 

 Edwards and Stockton Plateaus. The upper Cretaceous formation com- 

 prises the well known Black Prairie belt. The Black and Grand Prairies 

 are typical grass prairie country, possessing timber originally only on 

 the bottoms and breaks of streamways and escarpment bluffs. The pres- 

 ence of these features, however, together with the intrusions of two 

 tongues of sand bed country, known as the Cross Timbers, bring a con- 

 siderable amount of timber within this typically prairie region. The 

 intrusions of Cross Timbers may be considered geologically to be long, 

 narrow strips of sandy deposit extending north and south, the western 

 separating the lower Cretaceous from the Carboniferous area of the Cen- 

 tral Basin, and the eastern strip forming a line of division between the 

 upper and lower Cretaceous series. The latter is noticeable between Dallas 

 arid Fort Worth, while both become indistinct and disappear toward the 

 south. 



Formations, consisting chiefly of the Eocene or Lignitic belt and the 

 Fayette Prairie, are found to the coastward of the upper Cretaceous series, 

 and include in their southwestern extension the region known as the 

 Rio Grande Plain. Covering a region of heavy rainfall in the eastern 

 part of the State, these formations come within the continuation of 

 the Atlantic Forest Belt and are covered with a natural timber growth 

 of pine and hardwoods in East Texas, post oak, live oak, and other 

 hardwoods through the central portion, and characteristic chaparral 

 growth in the Rio Grande Plain section. From the Fayette Prairie to 

 the Coast, a narrow belt scarcely exceeding fifty miles in width, is known 

 as the Coast Prairie. Poorly drained and compact clays and silts alter- 

 nate with areas having a larger proportion of sand, which are more 

 porous and easily captured by forest growth. This one finds there 

 alternating areas of forest and open prairie. 



