branner: the stone reefs of brazil. 



29 



point and the village these rocks are strongly false-bedded, the false 

 beds being a metre thick. These black beds extend under the village 

 and appear at several places further up stream at low tide. The ex- 

 posures about the point are all covered by water during high tides. 





Fig. 8. 



Section showing the relations of the Maraanguape reef to the 

 landward sandstones. 



The top of these sandstones is about as high as the top of the stone 

 reef outside, but it was impossible to make out the structural relations of 

 the two. No fossils could be found in the dark beds. 



At the village of Suape, just south of Cape Santo Agostinho, a very 

 black soft sandstone is exposed on the sandy beach at low tide. The 

 exposure is only about ten metres long. The rock contains no fossils. 



At the Barra de Serinhaem, S. lat. 8° 36', these dark soft sandstones 

 are exposed along the river bank at low tide for a distance of several 

 hundred metres. No fossils were found in them. The church stands 

 upon these beds which at this spot rise about two metres above high tide. 



An important exposure of these rocks is uncovered on the shore be- 

 tween the village of Gamella and the mouth of Rio Formoso, S. lat. 8° 

 40'. Upstream on the north side of the river the Tertiary beds are 

 well exposed in a vertical bluff at the end of the hill upon which the 

 church stands. On the northeast side of this hill a low ridge strikes off 

 toward Gamella and the (encroachment of the sea -upon this ridge has 

 exposed its rocks well. The section is shown in the following sketch. 



Fig. 9. Geology of the beach at Gamella, Rio Formoso. 



The beds of this section below the thin seam of yellow clay are prob- 

 ably Eocene Tertiary, and are exposed in the bluffs south of the church, 

 but the snuff-colored bed and the white sands are not in that section. 



