Note 4 — Part II.

The slow progress of our agricultural exports during the first two hundred years of the history of this country, is in good part to be explained by the stubborn character of the soil which was then in use. The only easily subdued soils in use before 1800 were those of Virginia and Maryland. The sudden advance of the export trade in grain during the last fifty years marks the change which brought the great areas of non-glaciated soils of the Mississippi Valley and the South under cultivation.