OWER COUNTY. 361 



Devonian limestones.] 



No. 3. Heavy stone like that described at Austin, with clay filling the open planes 

 and joints 10 to 12 feet. 



No. 4. Rusty bituminous films . i to 1 inch. 



[On the authority of the owners of this quarry, to this section may be added the following:] 



No. 5. Limestone, filled with shells, blue, contains flint, makes lime, pene- 

 trated 3 feet. 



The bedding of No. 3 is here broken in a manner similar to that of Alderson's quarry 

 at Austin. The corners and angles of the beds are replaced by clay and the color of the stone is 

 changed from blue to buff or drab, to the depth of about two Inches. 



Some years ago the rock was worked by Dr. Barns, of Austin, about half a mile above 

 Gregson's mill. This quarry is now almost entirely flooded by the dam. The abutments of the 

 upper bridge at Austin came from this quarry, in part. Judge Ormanzo Allen owned a quarry 

 still above Barns that was also considerably flooded by the same means. The quarry most worked 

 was just above the mill, owned by M. J. Woodson. It is now entirely under water. Stone is 

 still taken out, however, all along, both above and below Gregson's. The beds at Gregson's show 

 very nearly the same characters as at Austin. The descent of the stream is over about fourteen 

 feet of rock, the layers of which are sometimes two feet or more in thickness, or massive, much 

 like an indurated shale. In weathering these thick beds are checked by planes running mainly 

 horizontal, instead of perpendicular or diagonal. Although mainly horizontal, these planes are 

 apt to unite after a few feet, splitting up the heaviest beds into wedging, lenticular masses. Some 

 parts are here plainly calcareous, affording traces of fossil remains that have the appearance of 

 brachiopods. These portions are porous as if by the absorption of fossils. 



At the mouth of Rose creek about the same thickness of the same kind of stone can be seen 

 in the bed and banks of the creek. A fine exposure is owned by J. D. Woodard in the right bank 

 of Rose creek near the crossing of the road from Austin to Officer's mill, perhaps a mile above its 

 union with the Cedar. It is again seen above Officer's on the land of Col. Lewis, on the east bank. 



At W. H. Officer's mill the left bank of the river shows about twenty feet of bedding. This 

 is one mile below Rose creek. South of this mill rock of the same kind is seen at a number of 

 places before reaching the state line. At two miles below Officer's it is quarried on R. B. Foster's 

 land, and on Mrs. John Niles's, sec. 4, Lyle. At the last place it verges more toward a sandstone. 

 It has been put into the foundation of a proposed mill by Alderson and company. 



Two miles east of Officer's mill a farmer struck the same rock in two geparate wells on his 

 farm, in one at the depth of three feet and in the other at eleven. 



Dobbin's creek, which joins the Cedar at Austin from the northeast, furnishes a water-power 

 of fourteen feet by dam. where a mill is erected. A quarry in the left bank of this creek shows 

 the same rock. The bluffs of the creek just below the mill rise about thirty feet, and show about 

 twenty feet of rock. The beds are in every place greatly broken, and in some cases displaced. 

 The rock is parted into blocks of varying size, according to the thickness of the layers, the upper- 

 most being finest. Throughout, the partings and all the interstices are closely filled with Creta- 

 ceous clay, making the whole a close and almost impervious mass. It has very much the aspect 

 of the Cretacc ous on the Cambrian, as seen at Mankato,* except that the small cracks and openings 

 are here all filled densely with the clay. 



On the S. E. i sec. 12, Win-lorn, Mr. Thomas Smith struck the Austin rock in making ex- 

 plorations for coal, at a depth of about 34 feet. In the extueme northwestern corner of Mower 

 county it was struck by a farmer in digging a well. It there has the form of the fine-grained 

 sandstone seen at Austin. The surface features that prevail at that point pass into the north- 

 western corner of Fillmore county, and cover the most of Sumner township. Southward, at 

 Spring Valley, a similar stone appears in the north side of the creek, where it has been opened for 

 building purposes by Mr. James Wilder and Henry Thayer. This stone is, however, more dolo- 

 mitic, and contains large Strophomence, and is thought to be allied to the Lower Silurian, though 

 its palaeontology has not been learned yet sufficiently to warrant any positive sentiments concern- 

 ing its age. 



Hudson Ricer rocks ? At two points within the county has been seen 



*See the second annual report; also the report on Blue Earth county. 



