FILLMORE COUNTY. 



287 



Shakopee limestone.] 



siderable disseminated sand, and nodules of calcite. The calcite is some- 

 times purely transparent, so as to exhibit the double refraction of Iceland 

 spar, parting into large rhombohedrons, but the most of it is opaque. It is 

 sometimes interspersed with sand grains taken up in the process of crys- 

 tallization. These are so abundant as to make, of some crystalline masses, 

 a sandstone which is then nodular and hard, with warty projections. 



At Parsley's ford, center of section 15, Chatfield, a bridge has been 

 built over the river, the abutments being of the Shakopee stone taken out 

 near the ford on Mrs. Doyle's land. At the ford the river is on the Jordan 

 sandstone. There has been considerable stone cut off the bluffs, in the 

 Shakopee, for use in the railroad bridge near the same place, and laid up in 

 heavy blocks; but much of the Shakopee is in irregular and thin layers, 

 unfit for such use. 



At almost any point east of Chatfield and Carimona the Shakopee can 

 be seen by one crossing the valley of the Root river, exhibiting its peculiar 

 tendency to narrow the valley, and forming a conspicuous bench or shoul- 

 der. The following diagram of a general profile section of the valley illus- 

 trates its form at points between Preston and Lanesboro; also between 

 Chatfield and Lanesboro along the north branch. At Preston the rocks 

 show a dip to the south. 



3 to 5 Mil as 



FIG. 18. GENERAL PROFILE SECTION ACROSS THE VALLEY OF ROOT RIVER. 



Bj'Itlanation. 



1. Galena or Upper Trenton limestone. 



2. Green shales. 



3. Trenton limestone. 



4. St. Peter sandstone. 



5. Shakopee limestone. 



6. Jordan sandstone. 



7. St. Lawrence limestone. 



At Isinour's station the battlements of rock that enclose the valley, 

 rising about thirty feet above the water, are of the Shakopee. There is an 

 undulating ascent thence over the St. Peter to near the Trenton terrace, 

 which rises nearly perpendicular about fifty feet. Beyond that is a flat, 

 running sometimes but eight or ten rods, but not unfrequently a quarter 



