Waring.: Geology of Northeastern Brazil. 223 



apart, having respectively flows of about two and one-half, one-half 

 and one-third liter per minute. The water is slightly sulphuretted 

 and tastes slightly sweetish. The springs are protected by curbing 

 and shelters, and have long been used for medicinal bathing. The 

 temperature of the water, 36° C, (97° F.), and the abnormally steep 

 dip of the sandstone at the locality indicate that the water may rise 

 along a fault plane. 



The spring on Fazenda Cache, fifteen kilometers southwest of Sao 

 Joao do Piauhy, or about eighty kilometers southwest of Simplicio 

 Mendes (in the southwestern corner of map (PI. IV) was visited by 

 Small, ^* who found that although it is locally called a hot spring, the 

 temperature does not seem to be abnormal, the term being applied 

 because of the escape of gas, probably carbon-dioxide, which gives the 

 water the appearance of boiling. The water rises in a shallow pool 

 of slight overflow, at the base of sandstone slopes, just above the 

 contact of the sandstone with underlying calcareous shale. 



Olho d' Agua Encantada (Enchanted Spring), a few kilometers east 

 of Mossoro, has been noted by Crandall,^^ who says that it is regarded 

 by the people as being very extraordinary, because of the alternate 

 appearance and disappearance of the water, and because at times they 

 are unable to enter the grotto where the water issues, due to the gas, 

 which is given ofi". He states that evidently there is here a production 

 of carbonic acid gas, which alternately causes the spring to flow, by 

 forcing the water up, and then escapes and itself fills the grotto. 



^■^ PubL No. 32 of the Inspectoria, p. 144. 

 ^5 Publ. No. 4 of the Inspectoria, pp. 41-42. 



