222 ORVILLE A. DERBY 
most casual inspection (which, except in limited areas, is all that 
it has yet received) into two distinct divisions, each of which will 
40° 
Rio Pircabas 
Maria Farinha 
“If Persar72Luco 
70° 
2Oe 
doubtless be found susceptible of subdivision. These are: (1) a 
lower series of sandstones, shales, and limestones, which are in part 
fossiliferous, and which have been subjected to slight earth-move- 
ments, giving the beds a moderate but irregular dip; and (2) an 
