BRANNER: THE STONE REEFS OF BRAZIL. 119 



2. The inclination of the reef beds. 



3. The elevation of the stone reefs beyond the reach of the high tides. 

 (Capanema speaks of the recession of the sea in the same sense.) 



4. The lakes along the coast. (Capanema refers to lakes shut off by 

 sand-banks.) 



5. The fixed dunes of the coast. 



To this list may be joined two additional points held by Capanema ; 

 namely : — 



6. Islands joined to the mainland. 



7. The conversion of a deeply indented coast-line into a weakly in- 

 dented one.^ 



It may be said at the outset that whether there has or has not been 

 an elevation of the coast in question, in uiy opinion the facts to which 

 appeal is made in these cases are either not facts at all, or else they do 

 not admit of the interpretations given them. 



These points will be briefly considered in their order. 



1. Uie schistose structure of the reef rocks. — It is presumed that the 

 idea here is that schistosity would have been produced by orogi-aphic 

 movements. However that may be, in the many kilometres of stone 

 reef examined by the present writer, what is commonly regarded as 

 schistose structure has not once been observed in the reef rocks. In 

 places the rocks sometimes contain mica, and are therefore somewhat 

 foliated, and it seems probable that this foliation may have been re- 

 garded by Liais as schistosity. The mica that causes the foliation was 

 deposited with the sand. 



2. The dip of the reef rocks. — Liais considers the angle of slope of the 

 beds {op. cit., p. 545) as having been produced by orographic disturbance, 

 the inference being that the strata were originally horizontal. It is true 

 that the beds of the rock reefs do have a dip varying between two and 

 twenty degrees, and in a few cases running a little higher. But the dip 

 is usually low and uniform and invariably toward the sea ; it is simply 

 the bedding of the beach sands of which the reefs are made. Such dips 

 may be seen in the wet sands of the present beaches. ^ I have lately 

 made notes upon the angles of the wet sand uncovered at low tide alone 

 the coast of Pernambuco and Alagoas. These angles run as high as 

 twenty-four degrees in false beds. A newly formed delta in the Una 



1 Mittheilungen von Dr. Petermann, 1874, p. 2.30. 



2 A. de Lapparent. On this subject see Traite de goolosiie, p. 173, 175. Paris 

 1885. 



L. Elie de Beaumont. Lecons de geologic pratique, Vol. I., p.226-227. Paris, 1845. 



