VEGETATION AND SOILS. 451 



heavily timbered with pine interspersed with hardwood on the more 

 elevated lands. The Archaean region is generally heavily timbered, 

 north Wisconsin being one of the great lumbering districts of the 

 continent. 



Geologically, we may distinguish the drift, the purely sandstone, 

 the purely limestone, and the crystalline rock soils. The last three 

 terms are meant to apply to such soils as result exclusively from the 

 disintegration of the underlying rocky formations. Inasmuch as these 

 formations are not always perfectly pure limestone or sandstone, their 

 disintegration gives other ingredients to the soil than lime or sand. 

 The drift soils are either bad or good as the material is more largely 

 sandy, or shows a predominating admixture of clayey and calcareous 

 substances; those resulting solely from the disintegration of the sand- 

 stone, of the' poorest quality; whilst the limestone soils are usually 

 the best in the region. The crystalline rock soils are often good, but 

 as the region of crystalline rocks is nearly everywhere invaded by the 

 drift, its soils are commonly dependent upon the nature of the drift, 

 rather than upon that of the subjacent rock. In some portions of the 

 Archaean region, where either the drift is not present in very large 

 quantity, and the felspathic rocks have disintegrated into a good 

 clayey soil, as in the high land in the western part of Marathon 

 county, or where the drift is itself of a non-arenaceous character, -as in 

 much of Clark county, and in many places along the line of the Wis- 

 consin Central Railroad, excellent lands for farming are made by 

 clearing the heavy growths of hardwood timber. Where the drift is 

 more sandy, as in a large region about the headwaters of the Wiscon- 

 sin river, the land is worthless for agricultural purposes, though 

 frequently covered with a valuable growth of pine. Through the 

 sandy nature of the drift materials the sand region of central Wiscon- 

 sin extends in places far beyond the district occupied by the Potsdam 

 sandstone. In all of the region in which the last named rock is the sur- 

 face formation, and where the drift is either absent, or present in 

 small quantities only, or is altogether sandy in nature, as in most of 

 Adams, Juneau, Sauk, Jackson, Marquette, and Waushara counties, 

 in much of Columbia, and in places all along the valley of the Lower 

 Wisconsin, the soil is generally a loose sand, and the land of the 

 poorest quality. Where the drift overlies the sandstone and con- 

 tributes clayey or calcareous matter, as in the southern part of Adams 

 county, or the eastern part of Waushara, the land is often good. In 

 other cases, a good soil within the Potsdam area and where the drift 

 is absent seems to have resulted from the filling of valleys with fine 

 stream detritus, as along the valley of the Wisconsin; or from the 



