Geological Recon7ioissancc in N. M. — Herrick. 343 
by the tracks of innumerable cattle and sheep. Suddenly we 
descend almost without warning into a large circular basin 
from the centre of which rise two cones of black basalt. The 
walls of the depression, which is somewhat over a mile in 
diameter, are formed of Fox Hills sandstone on the south, 
cast and west, while the northern wall appears to be of basalt. 
The two basalt cones some no feet high are approximately 
in the centre of the basin and the western one still preserves 
its conduit, which, in this case, is filled with a saturated solu- 
tion of pure salt. The salt lake is oval and about 210 feet long 
by 150 feet in width. Weeds blown into this crater lake are 
soon covered with crystals of pure salt. The second of the 
two peaks, a1)out 150 feet to the northeast, is a solid cone. 
North of these cones is a shallow lagoon of salt water, evi- 
dently fed from the crater lake. The lagoon is some 4,000 
or 5,000 feet long and about half as wide, and has been the 
source for salt for the whole region for an unknown period. 
The Zuni Indians assert a special claim upon the lake and as- 
sociate with it numerous curious superstitions. It is asserted 
by those who have gathered salt here, that by opening springs 
at the base of the cone the supply of salt in the lagoon was 
increased. Numerous fresh-water springs flow into the 
lagoon from the margin of the depression, yet the water in 
the lagoon during dry weather is a little more salt than that 
from the crater. The specific gravity of the lagoon water in 
December was 1.205, corresponding to about 26.08 salt, while 
the crater water is 1.145, corresponding to salinity of 19.03 
per cent. It was not possible accurately to estimate the 
amount of salt deposited in the lagoon, but at least three 
layers are known from eight to four inches thick, and large 
amounts are continually removed. The process is, however. 
a continuous one, as new precipitation is continually going 
on. A conservative estimate of the amount of salt in the 
water alone is 700,000 tons. 
The origin of the salt cannot be a difficult matter to ac- 
count for, in view of the fact that the conduit of the crater ex- 
tends to an unmeasured depth, evidently reaching into the red 
series which appears at the surface in the blufifs of the 
Carrizon. 
The depression about the cones has at some time been 
