6 AGKICULTURAL AXD MECHANICAL COLLEGE OF TEXAS. 



analog} 7 , and the wear and tear of time have scarred and disfigured the 

 relief. In general, the physical characteristics, or relief, are intimately 

 related to the geological formations. The composition and arrangement 

 of the various underlying rock sheets are responsible, not only for the 

 relief, but in a large measure also for variations and peculiarities in 

 soil and drainage, the vegetation and forests, and the agricultural and 

 industrial development of the State. (See Map 2.) 



Geographically, Texas may be divided into four large units or prov- 

 inces: the Central Basin or Denuded Area, the Trans-Pecos Province, 

 the Plateau Province, and the Coastal Plain. These are vast sub- 



Map 2 Geological Map of Texas. 



1-3 Older formations (chiefly granites in Central Mineral region) ; 4 Carbon- 

 iferous ; 5 Permian red beds ; 6 Jurassic (local in Trans-Pecos) ; 7 Lower 

 Cretaceous ; 8 Upper Cretaceous ; 9 Staked Plains or Llano Estacado ; 

 10 Lignitic belt: 11 Later coastal deposits (Fayette Prairie and 

 Coast Prairie) ; 12 Later Igneous outcrops. 



divisions and each is capable of division into several, important, smaller 

 units. 



The great Central Basin includes the Central Mineral region, of older 

 rock formations, the Carboniferous region, which lies to the north of it 

 along the eastern horder, and the Permian Eed Beds, which form the 

 western half of the Central Basin. 



The Trans-Pecos Province includes that portion of Texas west of the 

 Pecos Kiver. It is a complex region, there being involved in its struc- 

 ture rock strata belonging to almost every geological period. It may 

 be divided into several sub-provinces, two of which are the Stockton 



