The 1950 World Book Encyclopedia, the one my folks bought for us to learn from, includes a 16-page entry on North Dakota. There are pictures, charts and drawings and two maps. One is a “land use” map with little symbols depicting the principal products produced in different parts of the state.
The map has two ears of corn in the southeast corner. Heads of wheat and dairy cows are located in quite a few counties. Beef cows are found in much of western North Dakota, hogs in the southeastern part of the state and symbols for potatoes and sugar beets in the Red River Valley.