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In the moutitains ‘of that neighborheod common, limestone and sul- 
phate of lime’are said. to exist ; saa on the road. over which I travelled I 
had no chance to see an 
Granitic and trap formations seem. to pred minate, too, in the valley of 
the Rio del Norte below Santa Fe ; but as the road leads always along the the 
‘tant, E could pot examine them as I wished ‘to do, had often to de- 
pend alone upon the external form of the mena spel apparently i in- 
dicating unstratified and igneous S00 are er the maqntains ap- 
preached the river, | gained more infor 0, for none I found 
betweeu re pi ba (about 115 He ae “Santa Fe). quartzose sand-_ 
Stone and quariz in a spur of the eastern mountain chain; and in Joyita 
itself, bluffs near the river of amygdaloidal basalt. 
ome miles west of Socorro, (140 miles,)on the right bank of the river, 
i { seamed the western mountains, and found porphyritic and trachitic 
rocks 
Near the ruins of Valverde (165 miles) I met with bluffs of a dark. 
brown, nodular, “sreeeagel and about eight miles beyond, with Suny Eien 
loidal basalt agai 
In the cee del Muerto granitic and basaltic formation, to judge from 
their shape, exists in the distant mountain chains; partof them in the 
eastern chains is called, for their basaltic appearance, Organ mountains. 
elow Donana I perceived some primitive rocks again, near the river, 
resembling a Socom poned porphyry 
The mountains above el. Paso else maialy to the trap fo mation. 
‘Durip i my short ‘in el Paso 1 made an excursion to the ,south- 
western car BEAae of be walley, oad was rather Astonlenye to oe ae 
tains of limestone:..'The foot-of the mountains was by..a hori. 
zontal quartzose brandnehtings similar to that underlaying an amy gdaloidal 
basalt. ‘The very compact and. gray ligated s intersected with many 
white veins ef, calespar, rose upon it to the crest of the mountains; but 
sils, and though much. injured and imperfect, they a9 Lag hana suf- 
ficient e setae tie the age of this fermation. The. & ils are a coral: 
, and a bivalve shell of the genus Pter Th is limestone 
is therefore 7. Silurian. rock. ‘Several’ mines have eaily been worked 
ini 
On the road from el Paso to Chihuahua I met in the first day of two. 
with the same limestone. The pieces lying on the. road were gone 
that —_ are the result of aici sprip 
. ut 50 miles south of el Paso the pee Oe seems to cease, and por- 
phytic rocks of the most varied colors and combinations continued from 
here as far as Chihuahua, interrupted sometimes only by oe rocks. 
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Near C Chihuahua, I understood, about 12 miles northeast of it, moun- 
. iaei ? [ 26] 
