20 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY. 



At the northern end of this exposure are many lai-ge water-worn 

 granite boulders apparently weathered from a basal conglomerate. 



Going south along the coast from the Barreira do Camaragibe before 

 reaching the town of Santo Antonio da Barra Grande, one finds some 

 beautiful examples of coloring. The bluffs — there are several of them 

 — are about fifty metres high, and the rocks are red, pink, gray, white, 

 yellow, purple, orange, black, brown, and streaked and mottled, — all 

 combined to make a most brilliant bit of rock coloring. In the upper 

 part of this bluft' the bedding planes cannot be made out, and even the 

 colors appear only in irregular blotches, streaks, and bands. But at the 

 base of the clifi" there ai-e some beds still clearly defined as shales and 

 sandstones. 



At one place the upper part of the section is all gray and cream- 

 colored, while the lower part is fantastically splotched and streaked. 

 A coarse-grained sandstone is partly of a pearl-gray color with a vast 



Fig. 2. Bluffs of party-colored sandstones and shales fifty metres high 

 north of Santo Antonio Grande, State of Alagoas. 



number of sharply defined streaks and rings of brilliant cinnabar red 

 running through it. At two places the beds seem to be faulted, and 

 where the faults appear there are masses of unbedded white or gray 

 sandstone harder than the other rocks. These masses of sandstone have 

 the appearance of vertical intrusions. 



The exposure that first led me to question the validity of the so-called 

 Tertiai-y division of these rocks is at a place on the Alagoas coast known 

 as the Barreira do Boqueirao, a few miles north of the mouth of Rio 

 Manguaba. 



The following sketch (page 21) will give some idea of the geological 

 relations there exposed. 



The hills at Barreira do Boqueirao are some seventy metres high, and 

 the dip of the rocks is mostly toward the hills. The upper part of the 

 hills is of red, brown, purple, and yellow clays and sands nowhere clearly 

 separated from each other. To the left is a bed of fossiliferous bitumi- 

 nous shales, exposed for a distance of 150 metres, and dipping from 10° 



