OLMSTED COUNTY. 335 



Jordan sndstone.] 



that have been given of it in reports on Winona and Fillmore counties. 

 Its beds are quite irregular in some places, and show much chert and other 

 siliceous aggregations. It is sometimes compact and finely granular, but 

 is more frequently vesicular and with sparry cavities. The following sec- 

 tion was taken at Oronoco, at the lime-kiln of James Barnett, just northeast 

 of the village. 



Section at Oronoco, in descending order. 



" Calciferous sandstone, much broken in thin layers, buff 14 ft. 



Compact, little broken calciferous sandstone, light buff 2 ft. 



Sandstone (mostly saccharine) in layers 4 ft. 3 in 



Aluminous limestone, in thin layers, light buff 1 ft. 7 in.' 



Dark sandstone with numerous blue spots 1 ft. 8 in. 



Arenaceous vesicular dolomite 3 ft. 6 in. 



Like the second above 4 ft. 



Like the second above, but more irregularly bedded 1 ft. 



Vesicular, sparry, irregularly bedded dolomite 4 ft. 



Total, as far as seen 36 ft. 



In the above section no fossils could be found. The lowest layer is employed for making 

 lime. The lime is light buff, slow, and contains considerable cement. 



The Jordan sandstone. This sandstone, which was identified in 1873 as 

 a distinct stratunr in the Cambrian formations, separating the limestone 

 that Dr. D. D. Owen designated the Lower Magnesian into two important 

 and persistent members, has a thickness of about twenty feet in Olmsted 

 county. It can be seen at the mill-dam at Quincy on the Whitewater 

 below the Shakopee, with an exposed thickness of ten feet. It is here a firm 

 sandrock or granular quartzyte. West of Oronoco it is again visible in 

 some of the bluffs and mounds that rise above the Zumbro valley and reach 

 a hight of about 1100 feet above the ocean. About two and a half mile 

 west of Oronoco a slight excavation has been made in this rock tor its sup- 

 posed utility for building. It was done by Mr. Robinson; but the rock was 

 found to be rather poor, some of it being very fine-grained, and susceptible 

 of being carved into delicate forms. The most valuable result of the work 

 was the demonstration of the geological horizon hereabouts. The Shakopee 

 and Jordan cause the undulating country just north and west of Oronoco 

 The St. Lawrence is seen at Oronoco, rising about twenty feet above the 

 main part of the village, its upper line of outcrop running somewhat above 

 the dam. About a quarter of a mile southwest of Robinson's the Shakopee 

 and Jordan combine to form a couple of conspicuous mounds in the river 

 valley, in the same manner precisely as the St. Peter and Trenton combine 



