562 THE JOURNAL OF GEOLOGY. 



traced it over a large portion of the Plains, and while we have 

 no record of it on the top of the Cretaceous plateau between Big 

 Springs and the Nueces canyon, it may be there, and have been 

 overlooked owing to its close resemblance to Cretaceous mate- 

 rials. In the canyons, however, on the southern edge of the 

 plateau, its presence has been reported by Hill and Taff, and I 

 have traced its continuation southward from the line of the South- 

 ern Pacific railway to San Diego. While no direct connection of 

 these beds with those of the Llano Estacado has been observed, 

 their lithological identity and stratigraphical relations to the 

 Blanco beds below and the Equus beds above seem to warrant 

 the conclusion that a connection did exist either across or around 

 the Plateau. 



While erosion has removed the Reynosa from a large part of 

 the Guadalupe and Nueces valleys, it still caps the divides and 

 higher elevations and forms the surface of that plateau between 

 the Nueces and the Rio Grande which is in many respects the 

 homologue of the Llano Estacado, and may well be called the 

 Reynosa plateau. On this plateau it attains an elevation of over 

 eight hundred feet above sea level in an area which appears on 

 all topographic maps as lying below the 200 foot contour. 



In the Orange sand area the conditions are somewhat differ- 

 ent. The beds do not appear to have covered the entire area, as 

 did the Reynosa, but to have been laid down in drainage chan- 

 nels, lakes or bays among the islands or promontories of Eocene 

 materials. 



The Neocene deposits, taken as a whole, represent a period 

 of lacustrine, fluviatile and estuarine deposits. With the excep- 

 tion of the fossils obtained from the Galveston deep well there is 

 nothing to indicate marine conditions anywhere in the region 

 during Neocene times. 



At the close of the Pliocene the beds were elevated and sub- 

 jected to considerable erosion prior to the deposition of the 

 Pleistocene. The Sun mound, west of Waller, is an outlier of 

 the Orange sand, and Damon's mound, in Brazoria county, seems 

 to belong to the Reynosa, although many miles to the seaward 



