344 The American Geologist. June, i9co 
covered l)y the lagoon which has shrunken to its present di- 
mensions comparatively recently. The salt is practically pure, 
and when removed from the lagoon requires only to be 
washed in the brine of the lake to be sufficiently pure for table 
use. The salt has been used extensively in the amalgamation 
pans at White Water mill and is said to give better satisfac- 
tion than the Kansas salt used for the same purpose. 
The conditions which led to the opening of this old vol- 
canic conduit offer room for interesting speculation. It might 
be supposed that the gradual solution of the salt deposits per- 
mitted the neck to drop out of its place in the soft strata, or 
that the final eruption left the conduit open. At any rate, 
percolating water gradually dissolves the salt and allows it to 
rise in the crater whence it diffuses into the lagoon. The 
scene is an animated one when the ^Mexican miners in their 
shallow punts are engaged in gathering the salt by means of 
forks of many tines from the bottom of the lagoon. It re- 
minds one of the similar process carried on in the salt lagoons 
on the Tres Marias islands, though the deeper water makes 
it necessary to secure the salt by diving in the latter place. 
It would be possible to manufacture a very fine clean salt by 
employing the same process as is used in the Tres Marias. It ' 
would only be necessary to lay off a portion of the depressed 
area into shallow earthen tanks or basins a few inches deep, 
surrounding each basin with a raised bank. The basins 
should be in ranges at successively higher levels and com- 
municating with each other. The brine being pumped into 
the upper tiers would flow from one to the other tier as de- 
sired, and evaporation could be controlled very readily. The 
greatest dif^culty would be encountered during the windy 
season, and it might be necessary to suspend operations for a 
part of the year. Suitable wind-breaks and sheds might also 
be arranged. In this way a fine article could be secured at a 
minimum cost. The tanks should be lined with gypsum ce- 
ment, the materials for which are at hand in any desired 
amount. 
Turning northward the country is covered with the various 
m.embers of the red series which occupies, the surface over 
the entire western portion of our map including the Zuni 
country. A tongue of Cretaceous projects south-westward 
