GE1STESIS OF THE SOIL AND ITS POSSIBILITIES 189 



northern latitudes and extended down into these por- 

 tions of the United States already indicated, producing 

 important effects on the topography of the country. 

 When the ice melted the finely ground rock powder was 

 left, the glacial drift of to-day. This drift, sometimes 

 forming but a thin layer over the underlying rock, 

 sometimes forming a very thick layer, is made up of 

 the mingled materials brought from various geological 

 formations lying to the north of the place where they 

 are now found. The soils of this drift are usually 

 gravelly, often stony, of variable fertility, embracing 

 alike the noted fertile soils of Ohio and of western 

 New York and the most barren portions of New Eng- 

 land. As a whole, these soils grow more productive 

 as we travel southward and westward from New Eng- 

 land and western New York. As a whole they are 

 durable. When over-cropped and worn out even, as 

 often occurs, they readily recuperate, with rest, by the 

 slow disintegration of the mingled materials of which 

 they are composed. 



" According to geologists, the southern limit of this 

 drift-soil extends across Long Island, crossing New 

 Jersey at its upper third; thence across the State of 

 Pennsylvania, entering it and leaving it about midway, 

 entering Ohio near where the Ohio River strikes the 

 State, passing southwesterly, leaving the State near the 

 Ohio River, following along the southern borders of 

 Indiana in or near the southern tier of counties, not 

 crossing the river at all unless it be for a very small 

 region, where the three States of Indiana, Illinois and 

 Kentucky come together ; thence westward, crossing the 

 Mississippi above its junction with the Ohio ; then west- 

 war dly and a little northerly across the State of Mis- 

 souri, keeping south of the Missouri River, leaving the 



