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those spheroidal masses, fissured, and full of 

 cavities. Balis of this amygdaloid are enchased 

 in the gruenstein ; and this gruenstein alternates 

 on one side with a green slate, on the other 

 with the serpentine of Tucutunemo. Here then 

 is a connexion sufficiently intimate established 

 between the phonolites and the green slates, 

 between the pyroxenic amygdaloids and the 

 serpentines containing copper ores, between vol- 

 canic substances and others that are included 

 under the vague names of transition traps. All 

 these masses are destitute of quartz like the 

 real trap-porphyries, or volcanic trachytes. This 

 phenomenon is the more remarkable, as the 

 gruensteins, which are called primitive, almost 

 always contain quartz in Europe. The most 

 general dip of the slates of Piedras Azules, of 

 the gruenstein s of Parapara, and of the pyroxenic 

 amygdaloids imbedded in strata of gruenstein, 

 do not follow the slope of the ground from North 

 to South, but is pretty regularly toward the 

 North. The strata fall toward the chain of the 

 coast, as substances that had not been in fusion 

 would do. Can we admit, that so many alter- 

 nating rocks, imbedded one in the other, have 

 a common origin ? The nature of the phonolites, 

 which are lithoid lavas with a feld-spar basis, 

 and the nature of the green slates mingled with 

 hornblende, oppose this opinion. In this state 

 of things we may choose between two solutions 



