524 THE GEOLOGY OF MINNESOTA. 



[Soil. Timber and prairie. 



At the surface is a black soil, from one to three feet deep, being usually 

 about two feet, thus colored by vegetable decay, and consequently enriched 

 for the nourishment of the new vegetation of successive years. Otherwise 

 this soil is like the yellow subsoil, both being glacial drift. Everywhere a 

 sufficient proportion of the carbonates of lime and magnesia are present to 

 supply the best conditions for the cultivation of grain, and also to make 

 the water of wells and springs hard; but the sulphate of magnesia, which 

 occasionally appears as a white efflorescence where sloughs have dried up, 

 is yet only a comparatively small ingredient of the soil and very rarely 

 gives any parceptible taste to the water of wells.* 



The only areas unsuitable for cultivation are frequent sloughs, valu- 

 able for their marsh hay; the steep banks and bluffs of creeks and rivers; 

 and some portions of the morainic belts, which are so knolly and strown 

 with boulders as to forbid ploughing, but are well adapted for pasturage. 



Timber and prairie. Neither of these counties has any extensive tracts 

 of timber, which occurs only on the borders of lakes and along the larger 

 streams. In such situations it is wholly or partly protected from the 

 annual prairie fires, and is supplied with sufficient moisture to enable it 

 to maintain an existence. With double the rainfall that this region has, 

 it would probably become covered with timber notwithstanding the par- 

 tial checks which its spread must sustain from these fires; and with the 

 climate continuing as now, if fires were prevented, a forest would similarly 

 extend itself outward from the lakes and rivers over the whole of this dis- 

 trict and of this state. 



In Murray county the principal tracts of timber, consisting of elm. bass, bur oak, ash, poplar, 

 cottonwood, wild plum, and other species, are in the space, nearly a mile square, enclosed by 

 the Bear lakes; on the shores of lakes Sarah and Shetek, especially on the northeast side of the 

 latter, in the vicinity of Fremont lake; and along Beaver creek and the Des Moines river. A 

 grove of twenty or thirty acres, now wholly cut for fuel, was found bv the first immigrants on 

 the Chanarambie creek, in section 2, Moulton, and was named the "lost timber," because it was 

 the only considerable patch of woodland in that region, the nearest to it being at Bear lakes, ten 

 miles to the north. 



Nicollet says of his trip through this county :f "I pitched my tents, during three da\ s, about 

 toe group of Shetek or Pelican lakes, ihat occupy a portion of the space forming the Coteau des 

 Prairies. This name belongs to the language of the Chippewas, and lias been given to them by 

 the voyageurs. The Sioux call this group of lakes the Rabcchy, meaning the place where the peli- 

 cans nestle. Their waters are, in a great measure, supplied by a fork from the sources of the Des 



*An analysis by Prof. Dodge (Tenth annual report, p. 202)of an "alkali" efflorescence from section 14. lona, Murray 

 nunty. showed it to be a hydious sulphate ot magnesia, with slight traces of soda, potash and lime. The proportions 



" ilphur trioxide and magnesia were the same as in e*"""" if ~ 'U"-.o> "it K..* f* i...*i i~-o ii..*~ uif t, * 



:r of cryslallization required by epsomite. 

 tEeport on the upiter Mississippi, river, 1843 ; p. 13. 



of sulphur trioxide and magnesia were the same as in epsomite (Epsom salt), but it had less than half the percentage of 

 water of cryslallization required by epsomite. 



