288 THE GEOLOGY OF MINNESOTA. 



[St. Peter sandstone. 



of a mile, when a further gradual ascent begins, covering the Green shales 

 and the Upper Trenton. This last ascent, with the loam that here covers 

 the country, generally makes about 175 feet. 



H.O 



FIG. 19. 



At Carimona the Shakopee is visible in the banks of the river, rising 

 twenty-five or thirty feet. Its average thickness is about seventy-five feet. 



The St. Peter sandstone. The thickness of this well-known formation 

 in Fillmore county does not vary much from 125 feet. At Chatfield it 

 measures, by aneroid, 122 feet. In lithological characters it is uniformly a 

 clean, white sand that easily crumbles. Near Fountain an exposed section 

 near the top of the formation afforded fragments of an unknown species 

 of Lingulepis, the first and only fossil of any kind that had ever been re- 

 ported from this rock.* The following section was taken at this place. It 

 includes the overlying Trenton and the tjreen shales, as seen at the old 

 quarry of Mr. Joseph Taylor, section 13, Fountain. 



Section 'near Fountain. Quarry of Joseph laylor. 



No. 1. Green shale, embracing lenticular slabs of limestone that are eminently fossilifertus, seen 3 feet. 



No. 2. Limestone, of a bluish-gray color, in beds four to six inches thick, free from shale, though the layers are 



sometime!* thinly separated by shaly partings, 10 feet. 

 No. 3. Arenaceous and ferruginous shale, alternating horizontally with firmly cemented patohes of sandstone, 



2 feet. 

 No. 4. Massive, coarse sand; white, except when iron-stained;. containing irony, quartzyte pebbles, and fragile 



remains of bivalves. 



No. 5. Green shale, with some arenaceous and calcareous laminations, 3 feet. 

 No. 6. Cemented sandstone, the cement being shale and lime, forming when the bluff is weathered, the floor ol a 



bench, 1 foot. 



No. 7. White sand in beds that are about one foot thick and horizontal, 6 feet. 



No. 8. A course in the sandstone more firmly cemented, forming a table, but less persistent than No. 6, 1 foot. 

 No. 8. Massive sandstone, in some places showing an oblique lamination, seen 6 feet. 



I'i i il . T. C. Chamberlin has since reported organic remains, consisting of the tubes of Scolithus and fucoidal mark- 

 ings, in the St. Peter sandstone in eastern Wisconsin. Otology of Wisconsin, Vol. II., 1873-7, p. 288. See also the Dakota 

 county report. 



