Definition of "untilled"

The Emerald City was soon left far behind. As they advanced the ground became rougher and hillier, for there were no farms nor houses in this country of the West, and the ground was untilled.

1900 May 17, L[yman] Frank Baum, The Wonderful Wizard of Oz, Chicago, Ill., New York, N.Y.: Geo[rge] M. Hill Co.