406 THE CRETACEOUS AND TERTIARY GEOLOGY 



to near the mouth of the Rio Parahyba do !N^orte the coast is formed of a series of 

 soft, horizontally bedded, particolored tertiary sands and clays which are readily cut 

 and washed away by the ocean, the talus of which obscures any beds which might 

 otherwise appear at their bases. 



Cretaceous beds are exposed on the low gi'ounds of the island of Itamarica, 

 while the tertiary beds form the higher lands.* The relative positions of the creta- 

 ceous and tertiary upon this island favor the opinion that these same i-elations con- 

 tinue northwaid, and that the cretaceous of Parahyba is simply the northern exten- 

 sion of the Pernambuco beds. It is possible that a careful examination at low tides 

 of the beds along the coast and streams from Itamarica to Parahyba would settle this 

 question. 



No rocks referable to the paleozoic have thus far been found in the vicinity of 

 the Pernambuco basin. 



THE PARAHYBA EXPOSURES. 



N^o examination of the mesozoic exposures at Parahyba do Norte was made by 

 any member of the Commissao Geologica, and the only information that we have of 

 them is from a few brief notes by Williamson, Agassiz, and Capanema. The rocks 

 are soft, impure, gray limestones, dipping gently to the east, and containing but few 

 fossils. They occur near the city of Parahyba and at Minas da Cachoeira. Their oc- 

 currence at the latter place seems to add to the probability that the Parahyba beds 

 are simply a northerly continuation of the Pernambuco beds.f I have been unable to 

 obtain information regarding the age of the beds immediately underlying the creta- 

 ceous rocks of Parahyba. 



THE MESOZOIC BEDS OF CEARA AND PIAUHY. 



Our knowledge of the cretaceous beds of the interior of the province of Ceara 

 is derived almost exclusively from the observations and collections of Gardner made 

 just fifty years ago. With the exception of Capanema, the many writers who refer 

 to these beds have derived their information from him. 



The facts of most importance brought out by Gardner are the geological section 



* Relatorio dos Traballios da Coiiiinissm) Geologica do Brazil, por Cli. F. Hartt, Rio dc Janeiro, 1875, p. 10. 



t Among Uie fossils sent Dr. Wliiio from the Miiseu Nacional at Rio were some broken specimens of Toxaster altim- 

 cuius White, taken from the walls of ihe fort at the mouth of the river. As these specimens were collected by myself, I 

 quote from my fiehl notes written at the time, November the 25tli, 1875 : "I found some echinoderms and shells in the 

 walls of the old Dutch fort, at the nuiutli of the Uio Parahyba, but upon inquiring for the quarry from which the 

 stone came, I was told that it was brought from Europe ; at least that there are no quarries in the neighborhood yield- 

 ing such slonc." 



