HOUSTON COUNTY. 221 



Jordan sandstone.] 



from the vicinity of Caledonia. It is seldom quarried, or used for any pur- 

 pose, for the St. Lawrence limestone is generally accessible in the immediate 

 neighborhood, and that is much more desirable for building-stone, or for 

 lime-making. In descending the ravine toward the quarries east of Cale- 

 donia the Shakopee is the first limestone seen exposed. The quarries are 

 much lower, and in the St. Lawrence. It may be seen also in the upper 

 tributary valleys that feed Badger, Beaver, Crystal and Thompson creeks. 

 It causes the first rugged or rocky portion of these valleys. It is exposed in 

 the tops of the bluffs at the great spring, sec. 17, Caledonia, three miles 

 south of Sheldon. Its thickness at Mr. 0. A. Bye's, sec. 17, Wilmington, 

 when drilled through, was found to be sixty-four feet, which is probably 

 about its average thickness throughout the county. 



The Jordan sandstone. The lithological features of this sandstone, are 

 nearly the same as those of the St. Peter, but it has only about one-half the 

 thickness of the St. Peter. Its area of outcrop is quite small, and its ex- 

 posures are few. As it lies between two hard limestones, which are apt to 

 form perpendicular, walled bluffs, its line of outcrop is known by a belt of 

 non-exposure of rock separating the Shakopee from the St. Lawrence, which 

 is less steep in the ascent, and perhaps turfed over. It often becomes rusty 

 and firm from a cement of iron, when it endures long exposure, and is seen 

 as detached blocks in the valleys. Some blocks of this kind are visible by 

 the roadside in the ravine that descends to the quarries of Aiken and Moli- 

 tor, a mile east of Caledonia. 



The outcropping area of the Jordan is also frequently evinced by the 

 occurrence of blocks of firm sandstone in considerable abundance near the 

 tops of the bluffs. In ascending one of the numerous ravines of the county 

 after passing the precipitous outcrop of the St. Lawrence limestone, upon 

 ascending a gentler slope still higher, perhaps along a roadway, will occa- 

 sionally be seen such blocks of sandrock, varying from a few inches to a foot 

 or two feet in diameter, while the beds from which they are derived can 

 rarely be seen in situ; occasionally, however, they can. In some instances 

 the overlying Shakopee limestone, resembling greatly a weathered exposure 

 of the St. Lawrence, will also be found adjacent by pursuing the search in 

 further ascent of the same ravine. Mr. Moses Strong has reported similar 

 scattered blocks of sandstone at a level higher than the St. Lawrence lime- 



