chap. xni. Foliation of Mica-Schist, 453 



specified place my examination extended over an area 

 of several miles, and that Lieut. Stokes' observations 

 apply to a length of 100 miles, I think this remarkable 

 uniformity is pretty well established. The prevalence, 

 throughout the northern half of this line of coast, of a 

 dip in one direction, that is, to the west, instead of being 

 sometimes west and sometimes east, is, judging from 

 what 1 have elsewhere seen, an unusual circumstance. 

 In Brazil, La Plata, the Falkland Islands, and Tierra 

 del Fuego, tl ere is generally an obvious relation be- 

 tween the axes of elevation, the outline of the coast, 

 and the strike of the cleavage or foliation : in the 

 Chonos Archipelago, however, neither the minor details 

 of the coast-line nor the chain of the Cordillera, nor 

 the subordinate transverse mountain- axes, accord with 

 the strike of the foliation and cleavage: the seaward 

 face of the numerous islands composing this archi- 

 pelago, and apparently the line of the Cordillera, range 

 N. 11° E., whereas, as we have just seen, the average 

 strike of the foliation is N. 19° W. 



There is one interesting exception to the uniformity 

 in the strike of the foliation. At the northern point 

 of Tres Montes (lat. 45° 52') a bold chain of granite, 

 between 2,000 and 3,000 feet in height, runs from the 

 coast far into the interior, 1 in a ESE. line, or more 

 strictly E. 28° S. and W. 28° N. In a bay, at the north- 

 ern foot of this range, there are a few islets of mica- 

 slate, with the folia in some parts horizontal, but mostly 

 inclined at an average angle of 20° to the north. On 

 the northern steep flank of the range, there are a few- 

 patches (some quite isolated, and not larger than half-a- 



1 In the distance, other mountains could be seen apparently 

 ranging NNE. and SSW. at right angles to this one. I may add, 

 that not far from Vallenar Bay there is a fine range, apparently of 

 granite, which has burst through the mica-slate in a NE. by E. and 

 SW. by S. line. 



