Geological Prodromus. 63 
found near, to fortify the spaces which need it ; when there is a pro- 
portion of enmaderar, they do this, and then the pieces cut off are 
called tincas, which last in proportion to the quality of the wood, and 
to the weight they have to sustain. The excavations of St. Judas 
and Yanacantha, are lined with tincas. The tree of quenua, which 
grows in the Cordilleras, lasts longest, and I have seen pieces pulled 
out of old mines perfectly entire.* The mines of St. Cataline, Great 
Mine, Trinidad, St. Augustin and St. Rite, which are below the line, 
have pumps, aed by the Indians, twelve inches in diameter, set- 
tled in square calderas, well lined, from eight to ten yards deep ; : 
each one of them are two pumps, but in the first three mines are 
three stocks which throw from the first caldera, to the second, and 
this to the line; from the bottom of this caldera to the second, and 
this to the line; from the bottom of these calderas, they construct 
pipes, to the north and south, with a certain inclination, to extract the 
metals; and the space they leave is filled with stones and rubbish. 
The workmen enter the mines by puntas, and are ten or twelve 
hours, some pumping and others extracting the metal and sending it 
to the place of deposit, which is nearer the entrance ; those in the 
interior, rest three times in the space of half an hour, ‘tad this they 
call acullio. 
* * % * * * ii 
The sequel of the memoir, may be given in the next number. 
Arr. VI.—Geological Prodromus ; by Prof. A. Eaton. 
Ir having been announced in public journals, that Mr. Van Rens- 
selaer had ordered an extension of his geological surveys, and Mr. 
Cortlandt Van Rensselaer and myself having already travelled be- 
tween two and three thousand miles, the present summer, in pursuit 
of geological facts to fill up the chasms of former surveys, public cu- 
riosity may be in some measure gratified with the following :— 
* There is in the cabinet of Yale College, a piece of perfectly sound wood taken 
from an old Roman work in a mine which was wrought more than fourteen hundred 
years ago, and the wood is supposed to be of that age. 
oe 
ar 
