branner: the stone reefs of brazil. 33 



them as to give them the appearance, as seen from the ocean, of being 

 horizontal. 



At low elevations there are at many places a series of sediments newer 

 than, and resting unconformably against, the eroded Eocene rocks. 

 These beds have yielded no fossils, with the possible exception of certain 

 ones near Sao Thome on the Bay of Bahia, They are here tentatively 

 referred to the Pliocene. The break between the Eocene and Pliocene 

 is thus referred with doubt to the Miocene period. This would make 

 the stone reefs of the coast of Brazil a part of the Pliocene, or possibly 

 of Pleistocene and recent age. Doubts regarding the exact ages of the 

 Tertiary and recent deposits can be removed only by a more careful 

 search for fossils and a study of the fossils and of the living fauna of the 

 coast. 



The sequence of geologic events in the history of the coast since and 

 including Cretaceous time was apparently as follows : — 



Event. Time. 



1. The deposition of the Cretaceous sediments during a depres- 



sion of the coast Cretaceous. 



2. Deposition of the Eocene Tertiary sediments in the ocean and 



in fresh water lakes near the coast Eocene. 



3. Elevation, and erosion of land surface Miocene. 



4. Depression and deposition of the Pliocene sediments . . . Pliocene. 



5. Slight elevation of the coast ; erosion y ( Pleistocene 



6. Slight depression of the coast ?■ < to 



7. Elevation amounting to about two metres ) ' Recent. 



VOL. XLIV 



