PLATE XIV. 



FREEBORN COUNTY, 1884. N. H. WINCHELL. 



There is not a rock outcrop in Freeborn county. The surface is flat or gently 

 undulating, but rises to hilly in small areas. These hilly areas are parts of two belts 

 which cross the county from north to south, characterized by somewhat more rolling 

 surface than the prairies on either side.- The most rough tracts are in section 16, in 

 Newry township, and in sections 1 and 2, in Pickerel Lake township, the hills rising 

 from 50 to 100 feet above the adjacent surface. In general the whole county is one 

 of prairie, but scattering oak openings are found, while oak shrubs are common 

 about the shores of some of the lakes and along the. streams. 



The streams are small and sluggish, running through marshy tracts, but afford 

 water-power at Albert Lea and at Twin Lakes. The county has several fine lakes, 

 but their margins are apt to be marshy. Those in the morainic belts are exempt 

 from such marshes, and are generally deeper. In the western morainic belt are two 

 extensive sand plains, viz., Paradise prairie, north from Albert Lea, and the plain 

 known as Bear Lake prairie, in the southeastern part of Marshfield. 



Nothing is known directly as to the geological structure. It is inferred from 

 the known geology of some adjoining counties, and from the abundance of limestone 

 boulders throughout the most of the county, which were formerly much more 

 frequent, that the Devonian limestone underlies much of the county below the drift 

 and the Cretaceous. The deep wells drilled at Albert Lea for artesian water passed 

 mainly through a magnesian limestone, whose lithological characters were not diag- 

 nostic of the Devonian seen at Le Roy, in Mower county, but may appertain to the 

 Trenton (Galena) of the Lower Silurian. (Compare the Fourteenth Annual Report, 

 page 348.) This limestone, with its variations to shale and sand, has a thickness of 

 186 feet. The discharge of water in one of the Albert Lea wells was about 400 barrels 

 per day; but in the other, which started at a higher level, water stands at twenty-two 

 feet below the surface. In the latter rock was struck at the depth of 114 feet. 

 Other deep wells have since been sunk at Albert Lea, and they seem to indicate that 

 the Devonian lies nonconformably upon the Upper Silurian at a depth of about 275 

 feet beneath the city. Several wells with artesian flow have been obtained at 

 Albert Lea. 



The well sunk at Freeborn, in search for gas, went to the depth of 950 feet, and 

 its record was interpreted as follows: Drift, 150 feet; Galena limestone, 10 feet; 

 Trenton limestone and shales, 810 feet; St. Peter sandstone, 180 feet; Lower Magne- 

 sian (with its parts, Shakopee, Richmond and main body of limestone) and Jordan 



