nous sandstone or conglomerate is formed, which is the principal building stone of the region. In contact with decomposing organic materials, ferric oxide, the insoluble reddish coloring matter in the hills, is reduced to ferrous oxide, which combines with carbonic acid to form a carbonate of iron, which is soluble in water containing an excess of carbonic acid. Thus it is carried by the water to the bogs, where the carbonic-acid gas is exchanged for oxygen and the iron is precipitated in the form of ferric oxide; but, if there is a large quantity of decomposing peat present, it is deposited in the form of ferrous carbonate. Thus the so-called "bog iron ore" is formed.
The "raising" of this ore and the manufacture of iron there-from was the leading industry of South Jersey during the early part of this century. Charcoal was the fuel used and coalings were common throughout the "Pines." An active coaling is now seldom seen. Shells were hauled by wagon or rowed and poled by scow from the seashore for a flux, the oyster then being of more value for that purpose than for food. Better oysters could be picked from those shell heaps than can be bought at the stands to-day. In a memorandum kept by the "master ore-raiser" for one of the largest furnaces there are many interesting notices of large quantities of clams and rum bought and sold, but the oyster is never mentioned. These account-books were decorated with the pictures of soldiers and warships, showing well the prevailing thought of those days.
There was then an extensive trade between South Jersey and the West Indies, exchanging lumber and iron for rum, sugar, and molasses, in spite of the pirates who were ever at home in the thoroughfares, bays, and crooked channels of the coast. Scattered here and there along these streams are the remains of what were once centers of a flourishing industry. In some places the furnaces and forges have been completely obliterated and forgotten; in others only bits of black slag remain; while in others the ruins are still standing. At the head of the Tuckahoe River there is a crumbling stack, at Allaire there are ruins, and at Weymouth the course of a canal may be traced by which the ore was brought to the furnace from the bog.
The places were connected by stage routes, along which at regular intervals were the famous "jug taverns" of old, the ruins of which in many localities may still be seen. They are now in the midst of the forest, and, like the remains of the forges and furnaces, are sad reminders of more prosperous days. To-day one may wander for miles along these old overgrown roads without seeing a single human habitation.
In 1766 a furnace was built at Batsto, one of the first and at one time the largest in this country. Batsto is in the heart of the