544 Coquimbo. paet n. 



compact, smooth-grained, calcareo-argillaceous stone, 

 easily fusible, and emitting a strong" aluminous odour : 

 the whole has a highly angulo-concretionary structure ; 

 and it resembles, to a certain extent, some of the upper 

 tufaceo-infusorial deposits of the Patagonian Tertiary 

 formation. It is in its nature allied to our pseudo- 

 honestone, and it includes well characterised layers of 

 that variety ; and other layers of a pale green, harder, 

 and brecciated variety ; and others of red sedimentary 

 matter, like that of bed Three. Some pebbles of por- 

 phyries are embedded in the upper part. 



Seventhly : red sedimentary matter or sandstone 

 like that of bed One, several hundred feet in thickness, 

 and including jaspery layers, often haying a finely 

 brecciated structure. 



Eighthly : white, much indurated, almost crystalline 

 tuff, several hundred feet in thickness, including 

 rounded grains of quartz and particles of green matter 

 like that of bed Six. Parts pass into a very pale green, 

 semi-porcellanic stone. 



Ninthly : red or brown coarse conglomerate, 300 to 

 400 feet thick, formed chiefly of pebbles of porphyries, 

 with volcanic particles, in an arenaceous, non-calcareous, 

 fusible basis : the upper two feet are arenaceous without 

 any pebbles. 



Tenthly : the last and uppermost stratum here 

 exhibited, is a compact, slate-coloured porphyry, with 

 numerous elongated crystals of glassy feldspar, from 

 150 to 200 feet in thickness : it lies strictly conformably 

 on the underlying conglomerate, and is undoubtedly a 

 submarine lava. 



This great pile of strata has been broken up in 

 several places by intrusive hillocks of purple claystone 

 porphyry, and by dikes of porphyritic greenstone : it is 

 said that a few poor metalliferous veins have been 



