Stones suitable for important building purposes are usually found at a good distance below the surface. In the case of unstratified rocks, such as granite, the stone is most frequently detached from the mass by blasting, a process by which much valuable stone is wasted, and a different method is employed whenever it is found possible. In the case of stratified rocks, blocks are separated by hand tools alone. Small holes a few inches apart are cut along a certain length of rock, into which steel wedges are inserted. These are driven in by heavy hammers until the stratum is cut through. The large blocks necessary for monumental purposes are generally obtained in this way, and before they leave the quarry they are usually reduced as nearly as possible to a rectangular form.

Granite is a fire-formed rock which has been exposed to great heat and pressure deep down in the earth. It is one of the most abundant of that species of rocks seen at or near the surface of the earth, and was formerly considered as the foundation rock of the globe, or that upon which all sedimentary rocks repose. Granite supplies the most durable materials for building, as many of the ancient Egyptian monuments testify. It varies a great deal in hardness as well as in color and for that reason must be selected with care when desired for building purposes.

Granite abounds in crystallized earthy materials, and these occur for the most part in veins traversing the mass of the rock. Of these minerals, beryl, garnet and tourmaline are the most abundant. The decomposed felspar of some varieties of granite yields the kaolin used in porcelain manufacture. Granite is not rich in mineral ores.

It is abundant in America and is largely quarried in the United States for building purposes, especially in New England." The best known quarries are those of New England. There is a great deal of granite found in South Carolina and Georgia, but much of this, as well as that of some parts of California, is in a singular state of decomposition, in many places being easily penetrated by a pick. Granite quarried anywhere in which felspar predominates is not well adapted for buildings, as it cracks and crumbles down in a few years.

Granite Quarry A large quarry near Barre, Vermont. The rock occurs in what is known as "sheet formation.".

The Pennsylvania Railroad Company's "Broadway Limited," a Twenty-Hour Train.