IS'CLINATIOH or STRATA. 
83 
mfitoBoutb rf the ravine of Piedras Azules, are separated 
,l„r v‘ e grunstems and serpentine rocks that cover the 
clivity ot the mountains north of the ravine. In the 
present state of knowledge I find difficulties almost equally 
no doubt that e «! ler °i f theS ® su PP osifcious ; but I have 
t , a «“»“£ griinsteins (not the hornblende- 
hav beenLre .tr the gneiss 01111 mica -^tes, shall 
the bas'ilts Av ;H lCUtlVe y exammcd in other Prices ; when 
rocks* and tb» r\ Pyr ° Xen ?- ) formni S strata iu primitive 
ino ntabs sh 1 ,lt ! \ baSC \ and am >'S daloids m the transition 
exture of the l^ be ™ ca «*% studied; when the 
rf mechanic^ lave been subjected to a kind 
guS from the • VS1S ’ and $» 10nlbknd ^ better distin- 
SS Tnrit ? d the fffinrteins from the 
isolated and obscure wifi b phenon “ ;na now appear 
The phonolite and other lli ^ a ?g ed under general laws, 
are so muc the mn^ hft S lgneou ? ^8“ at ^rapara 
Of fracbjtes 3 ?' t?4 n po™h 
tiona.J ‘ ^ 1 or Pk}iy, basalts, and volcanic pro due- 
.t™’ s? tpp,t ch r is 
ments, being a thousand fee Me 7 barometrical measure- 
basin of Amgua F Jm thi -t ^ tbeb ° ttom of the 
Villa de Cura we deSSed t n ^5“T tabl f land of the 
Tucutunerao, which has hollowed for itselMn^, ° f tbe ,? io 
¥» S genee.U, north „d 
recognized in the m Lamina r' m 8 stratum of basalt has been 
and Raumer. (VoTtal'i geologists, MM. von Buch 
t The griinsfeioT , ! des R, escngel»rges, 1813 .) 
belong to the transition dat !^* 3 ° f Fichtel S cbir g e . i" Franconia, which 
i From the mo N? . 1 : ometlmes co “ ain Pyroxenes. 
~ - f ■» — i^siteS:. ~s i. sjsr^s c —' » 
a 5 
