86 ANNALS NEW YORK ACADEMY OF SCIENCES 



bowlders are not definitely known to exist in Brazil, I take this as a 

 strong evidence against Permian glaciation in Brazil. In fact, not until 

 recently has any one even seen striation in the alleged glacial deposits of 

 the Permian of Brazil. Some of these recent false signs of glaciation in 

 Brazil, as Branner has shown, even deceived Agassiz (the expounder of 

 glaciation), who described vast sections of Brazil as being glaciated. 



The direction of the striations and the arrangement of the bowlders 

 also offer no conclusive evidence in favor of glaciation. When "false 

 moraine," composed of scratched surfaces, bowlders and false tillite, be- 

 came covered up by the Permian sandstone found in the Plana Alto, 

 only those deposits and scratches pointing in the direction of the dip of 

 the country were exposed by the post-Permian erosion of the overlying 

 strata. In most of the Gondwana formation, this dip is toward the south 

 and west. Hence only here and there are the striae exposed, and all of 

 them point more or less in the same direction, i. e., they are only seen 

 along deeply eroded river valleys below the waterfalls. Furthermore, 

 these deposits often cover vast regions. For example, the deposits of 

 such erosion would have covered many miles of width for the entire 

 length of the Serra do Mar during the late Carboniferous and early Per- 

 mian when the climate was favorable for the deposition of false bowlder 

 tillite, which later became overlapped by the Permian sandstone. Later 

 erosion exposes these deposits over a vast area. 



Woodworth found striations on bowlders, some of which appeared to 

 have been deposited by ice floating near sea level (as is indicated by in- 

 tercalated marine deposits in the Rio Negro basin). This floating ice 

 may have come from Permian swamps, where it gathered up bowlders. 

 This mass may have floated toward the sea the following season, scratch- 

 ing the rocky surfaces along the margins of the swamps. In this case, 

 faceted bowlders would probably not have been formed. I acknowledge 

 that Woodworth has also found much other evidence for Permian glacia- 

 tion in Parana, Brazil, and the evidence is even stronger for it in the 

 eastern hemisphere, 40 



I grant that glaciers may have existed in Brazil during the lower Per- 

 mian epoch, but in view of the preceding, it appears that faceted bowl- 

 ders must be found before the evidence in favor of it is sufficient to 

 warrant the use of Permian glaciers as a factor in the distribution of 

 plants and animals. Even if such evidence is found in Brazil, it will 

 probably not be found after the lower Permian, at which time the typical 

 Gondwana flora and reptiles were scarce. Furthermore, if glaciers ex- 



40 Woodworth had not published his paper on the Permian glaciation in southern Brazil 

 when these notes were prepared. 



