282 
KANSAS CITY REVIEW OF SCIENCE. 
with the overlying igneous rock, sometimes following courses of natural joints or 
cleavage planes. 
The following tables, taken from the Engineering and Mining Journal, give 
the bullion output of Leadville for the year ended December 30, 1882 : 
QUANTITY. 
POUNDS OF 
POUNDS 
OF TONS OF OUNCES OF OUNCES 
BULLION. 
LEAD. 
OKE 
SILVER. OF GOLD 
Total 1st quarter . . 
. 23,487,082 
23.3^0,7 
43 12,9?4 2,042, 
323 3,c56 
Total 2d quarter . . 
, 20,510,096 
20,415,647 12,1' 
5 1,838,596 , 2,J86 
Total 3d quarter . . 
. 22,713,006 
22.605,015 28,0 
50 1,743, 
{576 6.548 
Total 4tli quarter . . 
• 19,747,065 
• 86,457,349 
19,646,027 36.9 
33 1,64^, 
31 7,273, 
454 3-923 
Total for year 1882 . 
86,047,4 
12"? 90, 1< 
249 16,413 
VALUE. 
VALUE OF 
VALUE OF 
VALUE OF 
VALUE OF 
TOTAL 
LEAD. 
SILVER. 
GOLD. 
ORE. 
VALUE. 
Total 1st quarter . . 
. $1,169,037 
$2,328,248 
$ 61,120 
$ 485,762 
$ 4,044,167 
Total 2d quarter . . 
. 1,020.779 
2,c93,3ci 
49,720 
599.059 
3,773,772 
Total 3^ quarter . . 
. 1,130,251 
1.988,142 
130,960 
1,326,111 
4,575,334 
Total 4th quarter . . 
942,977 
1,827.561 
$8,237,252 
78,457 
1,885,134 
$4,296,066 
4,734,129 
Total for year 1882 . 
. $4,263,044 
$320,257 
$17,127,402 
Total for 1881 amounted to $1 
3,170,576 
showing 
an increase this year 
;3,956,826. 
A GEOLOGICAL GUIDE TO MINE PROSPECTORS. 
PROFESSOR REUBEN WEISER. 
i^ ^ % -^ -^ ^ ^ 
We may inquire at this point as to the kind of rock, or rock formation-,, 
where silver or gold is likely to be found. This ought to be the first inquiry with 
the prospector who does not wish to throw away his time and money. The 
precious metals are found in nearly all the geologic formations, but in some more 
than others. Prof. J. D. Dana says, " silver veins often intersect trachite, por- 
phyry and other eruptive rock, or the sedimentary formation in the vicinity of 
such rocks." Trachite and porphyry are ancient lavas, and are found only in 
eruptive formations and outflows. Feldspar is the principal ingredient of trachite. 
It is a rough rock and has a bluish yellow color. 
Porphyry may contain silica and limestone. But silver is found most fre- 
quently in the gneissoid granite. Gneiss rock (pronounced nice) is a striated rock. 
It is found sometimes striped with black, red gray or white. Whenever you see 
a granite rock striped with these colors you may know that it is a gneiss rock. 
Silver is also found in amorphose granite; that is granite not striated. It is also 
found in limestone and in porphyry, in sandstone, in trap rock and in some 
shales. Silver and gold are found in all the geologic formations, from the oldest 
Azoic up to the most recent Tertiary. The principal gangue matter in silver 
lodes is calcite, which is carbonate of hme, pearl, fluor and heavy spar, which is 
sulphate of barium. This is easily known by its weight. It is about as heavy as 
