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bulletin: museum of comparative zoology. 



choked with sands thrown up across them by the waves, while their 

 upper portions have been filled up with silts from the land, and with 

 organic matter. There is a large number of small rivers whose lower 

 courses have had this histoiy. Only a few of them need be mentioned. 



Rio Guaju, at the bound- 

 ary between the State of 

 Parahyba and Rio Grande 

 do ISTorte, has a broad flat 

 bottom filled with sand, ly- 

 ing between rather steep- 

 faced hills. 



Rio Sibauma, a small 

 stream north of the Cun- 

 hahti, has a similar topog- 

 raphy about its mouth. 



The Pirangy, though al- 

 most closed by a high sand- 

 bank, has essentially the 

 same general topography. 



In the State of Parahyba 

 we have similar forms at 

 the mouth of the Miriri, 

 north of the capital, and 

 the Grahii, south of the cap- 

 ital, not to mention the 

 larger streams. In the 

 State of Pernambuco simi- 

 lar forms are common, 

 though often modified by 

 having the flat coast sands 

 built out beyond the steeper 

 bluff's, thus merging the flat 

 river valleys into the flat 

 sandy coast plains. 

 If good maps of them vv'ere available, some of the rivers about Bahia, 

 the Jaguaripe, for instance, would illustrate this matter beautifully. The 

 Jaguaripe, however, is very poorly shown upon the hydrographic charts. 

 Tlie sketch-map (Fig. 77), mostly constructed on the spot, will give, not 

 the exact form, but rather an idea of the generalized features of a portion 

 of the resion. 



