[1] The useful rocks, as granite, slate, sandstone, water-lime, etc., are not included. By “granite region” is meant one having rocks like New England, and therefore unlike Western New York or Illinois.

[2] That is, they are not so easily cut with a knife; they do not necessarily scratch marble.

[3] Only the best known localities in the United States are given. For these we are indebted mainly to Professor Dana’s great work on Mineralogy.

[4] From Simonin’s “Underground Life,” page 346.

[5] Church. The Comstock Lode, its Formation and History, N. Y., 1879, pp. 1-5.