chap. xv. Valparaiso to Coquimbo. 535 



CHAPTER XV. 



NORTHERN CHILE. — CONCLUSION. 



Section from Illapel to Combarbala ; Gypseous formation with sili- 

 cified wood — Panuncillo — Coquimbo; mines of Arqueros ; section 

 up valley ; fossils — Guasco, fossils of — Copiapo section up valley ; 

 Las Amolanas silieified mood, 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 salt- deposits — Metalliferous veins — Sum- 

 mary on the Porphyritic conglomerate arid Gypseous formations — ■ 

 Great subsidefice with partial elevations during the Cretaceo- 

 oolitic period — On the elevation and structure of the Cordillera — 

 Recapitulation on the Tertiary series — Relation between move- 

 ments of subsidence and volcanic action — Pampean formation — 

 Recent elevalory movements — Long -continued volcanic action in the 

 Cordillera. Conclusion, 



Valparaiso to Coquimbo. — I have already described 

 tlie general nature of the rocks in the low country north 

 of Valparaiso, consisting of granites, syenites, green- 

 stones, and altered feldspathic clay-slate. Near Coquimbo 

 there is much hornblendic rock and various dusky- 

 coloured porphyries. I will describe only one section 

 in this district, namely, from near Illapel in a NE. line 

 to the mines of Los Hornos, and thence in a north by 

 east direction to Combarbala, at the foot of the main 

 Cordillera. 



Near Illapel, after passing for some distance over 

 granite, andesite, and andesitic porphyry, we come to 

 a greenish stratified feldspathic rock, which I believe 

 is altered clay-slate, conformably capped by porphyries 



