FABIBAULT COUNTY. 459 



licd-rock in wellt.J 



with much certainty that the rock of the Winnebago City well is the Sha- 

 kopee limestone; and that the sandstone of the wells at Easton and Minne- 

 sota Lake belongs to the next higher formation, the St. Peter sandstone, 

 still retaining in these wells a thin cap of the Trenton limestone, which 

 directly overlies this sandrock at Minneapolis and throughout southeastern 

 Minnesota. 



The southeastward dip of these rocks, which carries them, with all the 

 higher Silurian formations, beneath the Devonian limestone of Worth and 

 Cerro Gordo counties in Iowa and of Mower and Fillmore counties in this 

 state, makes it improbable that the limestone or shale and underlying 

 sandstone encountered at Wells are the same with those of Easton and 

 Minnesota Lake. But the Palaeozoic series in this state and Iowa has no 

 thick beds of sandstone above the St. Peter; and the next geological age 

 which is represented in this region by such deposits is the Cretaceous. We 

 seem obliged, therefore, to refer to this age a formation of white sandstone, 

 about 60 feet in thickness, enclosing a layer three feet thick of limestone 

 and yellow shale at 21 to 24 feet below its top, which is found in the deep 

 well at Owatonna, succeeded below by the limestones and shales of the 

 Trenton group and the St. Peter sandstone (page 398). The same Cretaceous 

 sandstone appears to be the bed-rock struck by wells at New Richland in 

 southeastern Waseca county (page 410), half-way from Owatonna to Wells; 

 and at the latter place it seems probable that the layer penetrated by its 

 artesian wells corresponds to the limestone and shale enclosed in the Creta- 

 ceous sandstone at Owatonna, while this sandstone lies next below and is 

 found in C. W. Thompson's well to have a thickness of at least 34 feet. 

 The top of the strata which thus appear to be a continuous Cretaceous 

 formation has the following hights, approximately, above the sea: in the 

 Owatonna well, 1111 feet, the included limestone and shale being found at 

 1090; at New Richland, 1070; and at Wells. 1040 to 1050. These places lie 

 in a straight line, the distance southwest from Owatonna to New Richland 

 being eighteen miles, and to Wells thirty-four miles. 



Respecting the age of the limestone found in the well of section 4, 

 Seely, we can only say that the known stratigraphy and topography of the 

 region indicate that probably it belongs to either the Galena or Niagara 

 formations, intermediate between the Lower Trenton and Devonian, while 



