J. P. Kimball on the Silver Mines of Sta. Hulalia, Mexico. 169 
head of the arroyo, the dip of the limestone beds to the south- 
east is near 45°. The vertical axis of the boss is in the eroded 
neighborhood of the Vieja, at the confluence of another arroyo 
from the southwest. From this point in every other direction 
the dips (quaquaversal) are gentle, coming down gradually to 
not more than five degrees. But the steeper dips toward the 
outside of the limestone boss have brought up a great thickness 
of this formation (400 ft.) above the arroyo, and thus west of 
the Vieja the same strata are above its bed, as could only be 
entered by shafts east of this point. This is an explanation of 
the fact that below the Vieja all the workings are above the bed 
of the ravine, their openings being in the bluffs. These work- 
ings are all approximately horizontal: that is, they follow the 
stratification which on either side being slightly inclined from 
e ravine, gives them all something of a descent into the body 
of the hills. 
The San José enters the south bluff a quarter of a mile below 
It may be described as a series of caverns, natural an 
artificial, the largest in the district. It is here that is to be 
Seen the immense one already mentioned. ings extend 
n Eman- 
uel Escobar. The ores then coming out were plumbiferous. 
80 as to connect by — passages with the workings of the 
a a quarter of a mile o J 
& Jo. Its ores are excessively ferruginous ( 
- Color being that of red hematite. According to the owner they 
Lateseh 48 Ge 
: are now yielding 12 ounces to the carga ($103 to the ton.) 
