596 PERU. 
giving rise to hexagonal prisms. The following directions were noted 
down. 
. Southwest, and south. 
. Southwest one quarter west. 
. Southwes'-by-west and east-southeast. 
. West-by-south one quarter south and south-by-west. 
. West-southwest one quarter west, and south one quarter west. 
. West-by-south and south-by-west. 
too PF wwe 
. Southwest and south-by-east. 
There appear to be two prevailing directions, one about west-south- 
west and the other south ; while a third is sometimes apparent running 
east-southeast. Some of the fragments are quite regularly six-sided ; 
in other specimens the rhombic prisms afforded angles of sixty to 
seventy degrees, while at one locality the angle was about eighty de- 
grees. 
Dip—F aults.—The rocks of the island dip variously, yet the direc- 
tions are in general subordinate to an inclination, not exceeding twenty 
degrees, to the southwestward ; the layers consequently have the great- 
est elevation on the side towards the main land. 
The variations in the dip from this general course, have arisen from 
numerous fractures of the island, which have produced faults in the 
stratification. Four of these faults have been represented in the two 
figures just given; and they sufficiently illustrate their general cha- 
racter. The fault to the left (or south) in the second of these figures, 
amounts to five feet, and the rocks on the north side are the most ele- 
vated. The dip on the two sides remains the same, and amounts to 
about twenty degrees to the west-by-south. In the other fault, the 
rocks to the north have been uplifted ten feet, and received a dip of 
eleven degrees to the southwest. A fissure between the two separated 
parts is filled with fragments of sandstone and shale, which in some 
places are cemented by carbonate of lime. 
Along the same coast, farther to the northward, where the eighty 
feet of shale occur, there is a fault of much greater extent. This shale 
is horizontal in position; just south, there is a line of fault, beyond 
which the dip is that mentioned at the close of the preceding para- 
graph. The amount of displacement is at least fifty feet, and it may 
be more, as there is some uncertainty whether any of the shale to the 
north of the fault is represented by that to the south. This fault 
appears to be traceable above to the very summit of the island, where 
