 A large share of the surface is entirely unfit for cultivation, but the region is rich in minerals, and especially in an excellent variety of iron ore.In western New York, a series of hills forming spurs of the Allegheny Mountains enter the state from Pennsylvania and occupy the entire southern half of the west part of the state.An irregular line extending through the southerly counties forms the watershed that separates the northern and southern drainage; and from it the surface gradually declines northward until it finally terminates in the level of Lake Ontario.