BRANXEIl : THE STONE REEFS OF BRAZIL. 127 



riutn is reached between the resistance of the shores and the sea bottom 

 on the one hand and the waves and currents on the other. 



If evidence can be adduced from other coasts concerning whose history 

 we have more information, the case of the Atlantic coast of the United 

 States from Xew Yorli to Florida may be cited. This coast is sinking^ 

 and is characterized throughout a good part of its length by long straight 

 barrier beaches, sandspit harbors, and the silting up of the shallow 

 waters between the shore and the land barriers. 



Fwms on a stationary coast. — If a coast is at a standstill (not com- 

 pletely stable, for that is probably not true of any coast), the headlands 

 are attacked by waves, streams bring down silts from the land areas, and 

 these materials are thrown back upon the shores at favorable places, 

 forming spits, bars, and barrier beaches, while estuaries and embayments 

 are silted up and turned into dry land. 



The forms produced upon an old or stationary coast are therefore dif- 

 ferent from those produced upon a sinking one in that there are liable to 

 be fewer harbors or other indentations on the older or stationary coast, 

 and that islands generally common on a depressed coast are liable to have 

 been washed away. Or as Dr. James Geikie puts it, " A gently 

 sinuous or profusely curved outline indicates old coasts." ^ Gilbert 

 says that " simple contours and a cordon of sand, interspersed with high 

 cliff, make the mature coast." ^ 



Application to Brazil. 



Evidences of depression. — As a rule, evidences of depression are less 

 satisfactoiy, or rather they ai'e less impressive, than those of elevation, 

 because the parts principally affected ai'e carried down out of sight 

 beneath the water. 



To any one acquainted with the physiographic features of the north- 

 east coast of Brazil, however, it is evident that those features agree in 

 the main with those of a stationary coast or with those produced by 

 depression and age rather than with those produced by a recent eleva- 

 tion. There are very few islands, if we omit the coral reefs ; the coast- 

 line is low as a whole ; here and there headlands come down to the 

 water's edge, and between these the flat-floored valleys are covered with 



1 N. S. Shaler, Thirteenth Ann. Kept. U. S. Geol. Surv. for 1891-1892, Plate II., 

 p. 127. Washington, 1893. 



- Earth Sculpture, p. 317. 



- G. K. Gilbert. Lake Bonneville. Monograph I. U. S. Geol. Surr., p. 64. 

 Washington, 1890. 



