In 1907 Massachusetts ranked sixth among the states in the value of its trap rock product ($432,604), and eighth in sandstone ($243,328).
The greater part of Central India is covered with the well-known "black cotton soil," produced by the disintegration of the trap rock.
A noteworthy feature of this area is the series of trap rock ridges, between which the Passaic river makes its irregular way through a region of flat bottom lands.
Granite is found in Morris and Sussex counties, but is not extensively quarried; there are extensive quarries of sandstone in the Piedmont section; and limestone and trap rock are important mineral resources.
The excellence of the waggon roads of the state is largely due to the plentiful supply of trap rock in New Jersey.
