20 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
At the northern end of this exposure are many large 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 bluff 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 cliff there are 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 
5 N 
Ета. 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 
Tertiary division of these rocks is at a place on the Alagóas coast known 
as the Barreira do Boqueiräo, a few miles north of the mouth of Rio 
Manguába. 
The following sketch (page 21) will give some idea of the geological 
relations there exposed. 
The hills at Barreira do Boqueirão 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° 
