156 PROCEEDINGS OF THE ACADEMY OF [1895. 



and iu a comparatively short period the chief drainage outlets such 

 as the Sabine, Sulphur, Neches and the other smaller rivers had out- 

 lined their main channels and drainage areas. The Brazos and 

 Trinity rivers being already formed, enlarged their scope of opera- 

 tions, and here, we have also to consider the influences of the Red 

 River and Mississippi drainage systems on the coast. Fresh water 

 gradually spread over the greater portion of the regions and by the 

 deposition of the loads of mud brought down by the different streams 

 covered the flat, sandy country with a soft clayey soil. Irregularities 

 of deposition, accentuated by the irregularities of erosion and the 

 eternally changing conditions of the sand bars in the rivers and the 

 periodical flooding and low water changes in the rivers led to the 

 formation of irregular ridges of sand and the lenticular deposits of 

 clay we now find throughout the whole area. 



The damming of broad valleys of erosion by the sand bars at 

 their mouths formed wide tracts of marshy lands or lagoons and 

 these gradually acquiring a vegetation fitted for such localities 

 became the birth places of our extensive lignite beds. 



This condition went on year after year, periodical floods brought 

 into the marshes additional supplies of fresh water. There is no 

 reason to suppose there was a greater absence of the straining influ- 

 ences of the plants along the outer edges then, than now, and every 

 one can see this operation being carried on in marshy regions at the 

 present day. The presence of small trees occasionally found in the 

 lignite beds may be accounted for by the fact that during the course 

 of time these marshes acquired a suface soil of sufficient density to 

 support a growth of such swamp loving trees as cypress, gum, etc. 

 These grew, flourished and eventually dying, their trunks fell and 

 were buried in the soft vegetation of' the marsh. Some of them 

 appear to have left their stumps standing where they grew. 



During the course of time iu which these marshes and swamps 

 were growing it is reasonable to suppose that many of the uplands 

 and ridges between them acquired a vegetation. Marshy plants and 

 bushes fringed the pools and shed their leaves and branches into 

 them. Stronger trees grew on the higher grounds and the whole 

 country presented a forest clad appearance. Such a condition is seen 

 to-day along many of the rivers. Sloughs, ponds and "cut offs ' 

 are common along the Sulphur and other streams in the northeastern 

 portions. 



