metamorphic schists.--Foliation of intrusive rocks.--Relation of cleavage
and foliation to the lines of tension during metamorphosis.


CHAPTER VII.--CENTRAL CHILE:--STRUCTURE OF THE CORDILLERA.

Central Chile.--Basal formations of the Cordillera.--Origin of the
porphyritic clay-stone conglomerate.--Andesite.--Volcanic rocks.--Section
of the Cordillera by the Peuquenes or Portillo Pass.--Great gypseous
formation.--Peuquenes line; thickness of strata, fossils of.--Portillo
line.--Conglomerate, orthitic granite, mica-schist, volcanic rocks of.--
Concluding remarks on the denudation and elevation of the Portillo line.--
Section by the Cumbre, or Uspallata Pass.--Porphyries.--Gypseous strata.--
Section near the Puente del Inca; fossils of.--Great subsidence.--Intrusive
porphyries.--Plain of Uspallata.--Section of the Uspallata chain.--
Structure and nature of the strata.--Silicified vertical trees.--Great
subsidence.--Granitic rocks of axis.--Concluding remarks on the Uspallata
range; origin subsequent to that of the main Cordillera; two periods of
subsidence; comparison with the Portillo chain.


CHAPTER VIII.--NORTHERN CHILE.--CONCLUSION.

Section from Illapel to Combarbala; gypseous formation with silicified
wood.--Panuncillo.--Coquimbo; mines of Arqueros; section up valley;
fossils.--Guasco, fossils of.--Copiapo, section up valley; Las Amolanas,
silicified wood.--Conglomerates, nature of former land, fossils, thickness
of strata, great subsidence.--Valley of Despoblado, fossils, tufaceous
deposit, complicated dislocations of.--Relations between ancient orifices
of eruption and subsequent axes of injection.--Iquique, Peru, fossils of,