Sergipe, and Alagoas, Brazil . 



Fig. ?. 



023 



Fig. 7. Section showing the relations of the red sandstones to the fossil- 

 bearing shales in the well at fazeuda Jacii. 



The section passed through in the Jacu well, as furnished 

 me by Col. Larangeiras and his son Francisco Ferreira da 

 Motta, is as follows : 



Log of the Well at Jacu. 



Eock Depth 



Reddish soft sandstone 13*3 meters 



Somewhat harder sandstone _ . . _ . 6 -6 " 



Dark lead-colored shales, ) u 



with plant impressions \ " " 



23-2 meters 



There were no facilities for getting down in the well at the 

 time of my visit, but from what I could see from the surface 

 and from the character of the material on the waste heap and 

 the fossils found in the shales, the record must be practically 

 as represented. 



In the natural exposures the sandstones dip gently toward 

 the east, and in the well itself the beds are so nearly horizontal 

 that no dip is apparent. Col. Larangeiras says the sandstones 

 exposed hereabout continue as far as the plateau, some thirteen 

 to sixteen kilometers to the east, while my knowledge of the 

 geology of the plateau region leads me to infer that these 

 Estancia beds pass beneath the tablelands. 



The fossils found in the well at Jacu consist of the impres- 

 sions of ferns and occasional fragments of carbonized wood and 

 of siliciiied wood, all of which are scattered through the shales. 

 The fossil ferns are described by David White in the accom- 

 panying paper. 



The section and profile herewith will give an idea of the 

 geology of the region along the road leading southward from 

 Aracy to Serrinha. (See fig. 9.) 



