INEQUALITIES OF SEDIMENTATION 355 



They occur also in detached masses called chapeiroes on the coast 

 of Brazil which Hartt described as follows: 



Corals grow over the bottom in small patches in the open sea, and without 

 spreading much often rise to a height of forty to fifty or more feet like towers, 

 and sometimes attain a level of low water, forming what are called on the Brazil- 

 ian coast chapeiroes. At the top these are usually very irregular and sometimes 

 spread out like mushrooms, or as the fishermen say like umbrellas. Some of 

 these chapeiroes are only a few feet in diameter.' 



Lithiji cation. — Lithification of unconsolidated materials is a 

 potent factor in permanently fixing on the seashore and bottom 

 deposits of shifting sands, gravel, and other materials. Lithifi- 

 cation of loose sediments by the deposition of Ca2Co3 is subject 

 in a general way to latitude control. On the Atlantic coasts it 

 is a relatively unimportant factor north of Florida on the American 

 side and is seldom reported north of France on the European 

 coast. The action of this factor on the coasts where it is common 

 and important is highly irregular and as yet imperfectly understood. 

 On the northeast coast of Brazil it has produced the curious 

 wall-like reefs bordering the shoreline which have been described 

 in detail by Branner.^ Similar structures occur in the Levant 

 which have been described by Lartel,^ Hull,'' and others. Beaufort^ 

 shows that the ancient port of Pompeiopolis in Asia Minor has 

 been filled with dune sands which have become solidified on the 

 beach of the port. This case, Branner notes, shows that the lithi- 

 fication has occurred within historical times. 



At the island of Ascension Darwin found on the sea beaches 

 immense accumulations of small well-rounded particles of shells 

 and corals. At the depth of a few feet these were found cemented 

 together into stone. These calcareous masses had been under 



' C. F. Hartt, Geology and Physical Geography of Brazil (Boston, 1870), pp. 

 1 74-200. 



^J. C. Branner, "The Stone Reefs of Brazil," Bull. Mus. Comp. Zool., XLIV 

 (1904), 1-285, pis. 1-83C. 



3 L. Lartel, Exploration geologique de la Mer Morte de la Palestine (Paris, 1887), 

 p. 199. 



"• Edward Hull, Mount Seir, Sinai, and Western Palestine (London, 1889), p. 148.- 



5 Francis Beaufort, Karamania or a Brief Description of the South Coast of Asia 

 Minor (2d ed.; London, 1818), p. 249. 



