54 GULF TERTIARY OF TEXAS, 



and covered in its lower half by a heavy bed of detritus. The upper half is 

 composed of a series of light watery-green clay, with sand beds and calcareous 

 seams. : The upper thirty feet of this bluff is composed of sand, in places 

 hardened into a friable sandstone similar to those already described. It is 

 composed of sharp siliceous grains, and often contains black specks. Patches 

 of very coarse transparent sand the size of a mustard seed and larger occur 

 in it. Lumps of white or light brown clay and similar nodules of limestone, 

 from one-half to one inch in diameter, are of frequent occurrence. In some 

 places black oxide of manganese coats the grains of sand. Many impres- 

 sions of a palm or palmetto leaf, as well as silicified stems and trunks, are 

 found in the sand bed. From here to La Grange are low outcrops of the 

 same sand as caps Palm Bluff. They are of a very striking light watery-blue 

 color when wet, but gray when dry. 



"La Grange Bluff" is about a mile below the town of La Grange. It is 

 100 feet high and the lower part is heavily covered by alluvium and detritus 

 from above. The exposed part is composed of interbedded soft friable sand- 

 stones, white or yellow m color, specked in places by rusty spots of decom- 

 posed iron pyrites, and containing many small white calcareous and clay nod- 

 ules. The whole bluff offers very much the same appearance as "Palm Bluff," 

 and the sand varies from a very fine variety to that of the size of a mustard 

 seed. Frequently a hard clay is interbedded with the sands, and when dry 

 often weathers into nodules, due to its conchoidal fracture. The white calca- 

 reous nodules are in places so numerous that they form a conglomerate, with 

 sand or yellow sandy clay as a matrix. 



BRAZOS RIVER SECTION. 



As we descend the river from the " Moseley's Ferry" shell bed, which is the 

 uppermost fossiliferous Tertiary bed seen on the river, we reach, at a point 

 four miles below it and at the mouth of the Little Brazos, a rapid caused by 

 cross-bedded sands, with gray, black, and greenish clays in lenticular seams, 

 and containing many ferruginous concretions. For over two miles below 

 this are seen outcrops of gray sand and watery-green and chocolate clays, 

 with lignite beds up to one and a half feet in thickness. Many calcareous 

 concretions, one-half to two feet in diameter, are seen, as well as hardened 

 masses of clay and sand and a tremendous amount of silicified wood in loose 

 blocks. This wood was not seen in place, but occurred in the gravel drift 

 overlying this formation. Nine miles below "Moseley's Ferry," and in the 

 eastern part of Burleson County, is "Sulphur Bluff." The following section 

 shows the occurrence of the strata: 



1. Light brown hardened sandy clay 10 feet. 



2. Lignite 1 foot. 



