Yol. 6 3 .-] 



CRETACEOUS FORMATION OF BAHIA. 



129 



condition are mingled with the pebbles, as already observed by 

 Dr. Derby. The sandstones sometimes exhibit ripple-marked 

 surfaces, as at Pedra Furada and Periperi. There are also, both 

 in the sandstone and in the shales, small patches of bone-bed, 



Map slioiving the localities where Cretaceous fossils ivere found. 



containing not only the scattered remains of fishes, but well-rolled 

 pieces of reptilian bones ; a particularly-noteworthy bed at San 

 Thiago rests upon a shell-bearing layer. The shales are often 

 calcareous, and contain both hard concretions and soft muddy 

 pockets ; some are also impregnated with oil. 



