380 (t. A. Waring — Reef Formations of the 



entrance to this harbor is built on low slopes of brick-red sand- 

 stone, but at the beach about a mile beyond the light there is 

 a cliff, 15 or 20 feet high, whose material from a distance 

 resembles the gray rock at Fortinho. Although this calcare- 

 ous sandstone of the port of Aracaty does not form the typical 

 low, narrow reefs, it does resemble the sandstone of Ponta 

 Caicara.* 



The presence of a sandstone reef in the harbor of Fortaleza is 

 mentioned in a report on the betterment of the port, published 

 in 1875.f The reef described is apparently in the locality 

 now occupied by a breakwater that was built in an unsuccess- 

 ful attempt to form a quiet harbor. Xo evidence of a reef 

 was seen along this wall in 1913, but small areas of iron- 

 cemented sand and gravel along the neighboring shore indicate 

 that the reef is of this material rather than of calcareous sand- 

 stone. At two places along the beach between Fortaleza and 

 Ponta Mucuripe, 4 miles to the east, however, small masses of 

 fine-grained, very firmly-cemented gray to pale-yellow beach 

 sand were seen, partially buried at about half-tide level ; while 

 near the point, similar small masses of hard, fine-grained sand- 

 stone are firmly cemented to the red iron-sandstone in cavities 

 and seams, where the sand has evidently been blown from the 

 adjacent dunes by the wind. It would appear that under 

 favorable conditions small masses of beach sand deposited on 

 the iron-cemented sands may become firmly consolidated by 

 calcareous material. 



On the western side of the harbor of Camocim several 

 blocks of the typical calcareous sandstone are exposed on the 

 beach f to 1 mile north of the northernmost shipping pier. 

 Although it is situated well within the river mouth which 

 forms the harbor, the material very closely resembles the 

 typical reef material in texture and composition. It does not 

 form banks or cliffs, as does the calcareous material at Fortinho. 

 The occurrence of calcareous sandstone at Camocim is the 

 westernmost that was seen by the writer. There is none for a 

 distance of 8 miles farther west along the coast from this city, 

 and though small patches may exist beyond, inquiry among 

 the fishermen at Camocim failed to yield any information on 

 the matter. The material was not observed at the harbors of 

 Amarraeao, Tutoya and MaranhSo, respectively 60, 100 and 

 250 miles west of Camocim. 



* At several places on the beach behind the sand bar which prevents small 

 coasting steamers from entering the harbor at Fortinho except on the highest 

 tides, black clay, the remnant of a mangrove area, is exposed, and resembles 

 at a short distance a low reef. 



f Melhoramento dos Portos do Brazil, Relatorio de Sir John Hawkshaw, 

 pp. 89-91, Rio de Janeiro, 1875. 



