234 



a. The surfiice is covered with a few feet of a very fine, light 

 brick-red earth consisting of a mixture of clay and very fine sand. 



h. Red sandy clay packed fall of nodules of iron-stone, which are 

 elongate and stalactitic in form, and imbedded upright, so that the 

 bed appears as if it were full of long, irregular roots. Thickness 

 8-10 feet. 



c. Very heavy beds of Tauatinga clay of a grayish white color 

 magnificently exposed in the cliff's on the south-eastern side of the 

 serra, where they look white like chalk. These rocks are well 

 bedded as seen in the sketch of the cliffs, but they are not laminated. 



d. A thick bed of white clay, partly very pure Tauatinga, partly 

 sand and often presenting a structure similar to that of a brick in 

 which two kinds of clay have been imperfectly mixed together. 

 The material of wJiicli this bed is composed bakes very hard in the 

 sun, and, resisting denudation better than the overlying beds, it occa- 

 sionally forms a projecting platform with bluff" edges. 



e. Soft, fine-grained sand-stone, white or cream-colored, and with 

 a cement of clay. 



/. Sandy clay, not laminated, variegated in color and irregularly 

 solidified by iron oxide. 



Leaving the serra and going eastward a short distance to a deep 

 valley, the section appears to be continued as follows: 



g. A heavy bed of a hard, fine and even-grained, white, argilla- 

 ceous sandstone, beautifully variegated with bands and mottlings of 

 delicate shades of red, purple, brown and yellow. This rock resem- 

 bles very closely that of the little ridge just east of the igarape of 

 Ercre and may be of tlie same age ; but, uufortunately, in the valley 



