82 
THIRTEENTH REPORT. 
been the rise of the Ludington-Manistee district, and the region along 
the Detroit and St. Clair rivers. 
At present, the Ludington-Manistee district leads in production, hav- 
ing produced, in 1909 1 , two-thirds of the entire output of the state. 
Here the industry is likewise associated with the lumber industry, but 
one plant, the Anchor Salt Co., of Ludington, operating independently 
of the saw mills. Two processes are in use, the grainer and the vacuum 
pan, and the product, which is sold largely in bulk and barrels, is what 
is known as common salt in counter distinction to table salt. The 
Stearns Salt and Lumber Co. of Ludington, however, is planning to in- 
stall apparatus for the manufacture of table salt. 
The first attempt, in later years, to manufacture salt in the Detroit- 
St. Clair Rivers district was made at Mt. Clemens. While this effort 
was a failure, owing to the fact that the well did not pierce the rock 
salt but stopped in a brine-bearing stratum above, the brine of which 
was too impure to be successfully utilized in the manufacture of salt, 
it is especially interesting in that it lead to the discovery of the remark- 
able. curative properties of the Mt. Clemens mineral waters. 
When later rock salt was found, plants were established at many 
points along the St. Clair River, and then south of Detroit. So that to- 
day, companies are operating at Pt. Huron, St. Clair, Marine City, 
Delray, Ecorse, Wyandotte and Oakwood. In addition to these brine 
plants, rock salt is being mined at Oakwood by the Detroit Salt Co. In 
this district, nil types of manufacture, employed in Michigan, may be 
seen. Thus we find the open pan, grainer, vacuum pan, and Alsberger 
systems all in operation. The majority of the plants also make table 
salt. 
With the exception of the rocksalt produced at Oakwood, salt is 
manufactured in Michigan by the evaporation of brines, both natural 
and artificial. At various times, three different natural brines, each 
of which is obtained from a sandstone, has been employed. These brine- 
bearing sandstones are the Parma, the Napoleon, and the Berea. 
The Parma brine, while no longer used on account of its being weaker 
than the underlying Napoleon brine, is characterized by its purity. As 
may be seen from the analyses in table I, it is distinguished from the 
Napoleon and Bera brines by a higher percentage of calcium sulphate 
relatively to the early chlorides. This brine was one of the first used 
in Michigan and its utilization was limited to the Saginaw Valley. 
’Report State Salt Inspector, 1909. 
