OF THE SEUGIPE-ALAGUAS BASIN OF HltAZIL. 413 



in its general charactei's between such widely separated regions as the Amazonas and 

 Sergipe or Bahia is worthy of note. The description b}' Hartt of the tertiary hills 

 of Parauaqiiara''' might have been written of some of the Sei'gipe exposures with the 

 exception of the sequence of the various beds. The following is his section, begin- 

 ning at the top : 



1. A few feet of fino, light, brick-red earth, consisting of a mixture of clay and 

 fine sand. 



2. Red sandy clay with iron nodules. 



3. Tauatinga clay, grajish-white. Heavy bed, not laminated. 



4. White clay, partly pure tauatinga, partly sand, resembling brick of two im- 

 perfectly mixed clays. Bakes hard in the sun and resists denudation. 



5. White or cream colored, soft, fine-grained sandstones. 



6. Variegated sandy clay. 



7. Argillaceous sandstone vai'iegated with bands and mottlings of delicate shades 

 of white, red, purple, brown and yellow. 



The following section was observed near Maroim, and may serve as a type of this 

 foi-mation along this part of the coast : 



1. Surface soil, sandy, 4 feet. 



2. ^Mottled red and white clays, 3 " 



3. Blown sandstone, 1 foot. 



4. Chalky above, red beneath, 6 feet. 

 6. Terra-cotta colored sandy clays, 7 " 



6. Dark red, hard clays, 2 " 



7. Soft, light-brown sandstone, 3 " 



8. Soft white sandstone, 10 " 



9. Soft earthy sand, 1 foot. 

 10. Talus, princiiJally from Xo. 7, 15 feet. 



Not enough attention was paid to the tertiary to enable the writer to say 

 whether the secpience of the beds is at all uniform even wilhin the limits of the Ser- 

 gipe-Alagoas basin. 



Evidences of the Age of this Formation. — The series of rocks here referred to 

 the tertiary are so called upon stratigraphic evidence alone, for it is a vciy remarkable 

 fact in regard to these beds that, widespread as they an;, no fo-^sih liave cvci- b 'cn 

 found in them, though diligent search was made for them by the writer, and doubtless 

 also by others. But their relations to the cretaceous and their general resemblance to 

 the tertiary beds of other parts of the world scarcely leave any doiibl alidut the 



* Kill, liiif. Hoc. Nal. Scl., Jim , 1H71, 



