Hence we must conclude that both the Peuquenes and Portillo ranges were partially upheaved and exposed to wear and tear when the conglomerate was forming; but as the beds of the conglomerate have been thrown off at an angle of 45 degrees by the red Portillo granite (with the underlying sandstone baked by it), we may feel sure that the greater part of the injection and upheaval of the already partially formed Portillo line took place after the accumulation of the conglomerate, and long after the elevation of the Peuquenes ridge.

So that the Portillo, the loftiest line in this part of the Cordillera, is not so old as the less lofty line of the Peuquenes.

Evidence derived from an inclined stream of lava at the eastern base of the Portillo might be adduced to show that it owes part of its great height to elevations of a still later date.

Looking to its earliest origin, the red granite seems to have been injected on an ancient pre-existing line of white granite and mica-slate.

In most parts, perhaps in all parts, of the Cordillera, it may be concluded that each line has been formed by repeated upheavals and injections; and that the several parallel lines are of different ages.