TOPOGRAPHY. 21 



derivation, such as the Sabine and Neches. In the northern portion of the 

 area the main rivers flow a little south of east; further south their courses 

 are more nearly south. In the first case they belong to the drainage system 

 of Red River and its adjacent lake system, while in the latter case the drain- 

 age is towards the Gulf. 



"The Red River rises in the eastern slopes of the Staked Plains, in North- 

 ern Texas, passes through the Red (gypsiferous) Beds, the Paleozoic rocks, 

 and the great Cretaceous area of Central Texas, and finally deposits in East 

 Texas a sediment composed of materials from these regions, in the form of 

 a highly calcareous red silt. The Trinity rises in the Carboniferous rocks of 

 Northern Texas, but far east of the Staked Plains, and passing down through 

 the Cretaceous prairies becomes charged with calcareous matter. Hence its 

 sediments, though often calcareous, do not have the red color of Red River. 

 The Sabine rises still east of the Trinity, while the smaller rivers, such as 

 the Neches and Angelina, rise in the timber region, and the character of the 

 sediment of them all varies with the region they rise in and flow through. 



"Though traces of gravel and river silt are found along the rivers, and 

 sometimes reach down to the water's edge, yet all of them may be said to 

 flow in channels cat in the older sediments, as such strata crop out at very 

 frequent intervals along their courses. In this respect they resemble the 

 Mississippi, in connection with which a similar statement has been made by 

 Humphreys and Abbot.* 



"All of the Texas rivers are navigable to a greater or less extent, and until 

 the introduction of railroads an extensive shipping business was carried on in 

 transporting the cotton production of the region. Of course the amount of 

 freight that could be carried depended on the high or low condition of the 

 water. Now, however, boats rarely go up them for any considerable distance, 

 as the journey takes a long time on account of the currents in the rivers, and, 

 consequently, competition with railroads is impossible. The Sabine was for- 

 merly navigated for three hundred miles from its mouth, while cotton boats 

 capable of carrying one thousand bales made regular trips up the Trinity to 

 Green's Landing, in the northwestern part of Anderson County." 



The rainfall is very considerable throughout the district, being greatest dur- 

 ing the winter and spring, and the erosion is proportionally extensive. The 

 soft, unindurated character of much of the material composing the geological 

 formations of this region are very favorable to the percolation of water, and 

 springs are very abundant in every portion of the district. This soft condition 

 of the materials also renders the work of erosion the more easy and rapid. 



These agencies are steadily continuing the work which has already sculp- 



* "Report on the Physics and Hydraulics of the Mississippi River," by Capt. A. A. Hum- 

 phreys and Lieut. H. L. Abbot. 1861, 



