CASS COUNTY. 89 



as far as possible the larger siliceous particles, and then by drying and roast- 

 ing at a red heat, to render these ores sufficiently magnetic to be concentrated 

 by some of the numerous magnetic separators now in use for magnetites, and 

 by these means be rendered fit for use; but in the present condition of the 

 iron markets of the world and the large quantities of better and more easily 

 obtained ores lying useless, these operations could not be carried on without 

 entailing considerable loss to the proprietors of the mine or furnace attempt- 

 ing to use such ores. 



FERRUGINOUS SANDSTONE. 



In some localities throughout the county the ferruginous sandstones contain 

 a considerable quantity of oxide of iron, many of them showing as high as 

 thirty or even thirty-six per cent of metallic iron. The quantity of silica in 

 these sandstones, however, make them of little or no value from a metallurgi- 

 cal point of view. 



These deposits are as a rule very broken, and can not be said to have any 

 regularity of bedding or deposition. They lie in irregular heaps or masses 

 of roughly shaped bowlders, and from their positions appear as if at one time 

 regularly stratified, but afterwards broken up by their own weight, owing to 

 the withdrawal, by erosion, of the underlying sands. The roughness and 

 irregular form of the bowlders forming these sandstone deposits are due to 

 atmospheric action caused by the rain, wind, change of temperature, and in 

 some cases partly to the action of vegetable life. 



In some instances these sandstones may be utilized for building material 

 where the roughness of the material will not form an objection, such as in 

 foundations of buildings, or any other underground work, with the exception 

 of well curbing or cistern lining. As a general thing, however, they are too 

 soft to be readily worked or to stand any great amount of weathering where 

 it might be necessary to use them in the construction of buildings. Some 

 have been used by the people throughout the country for building chimneys 

 and fireplaces, but with only partial success, and the general verdict of those 

 who use them is that these sandstones are unsuitable for that purpose, owing 

 to their tendency to break into small fragments when heat is applied to them. 



CLAYS. 



The clays of Cass County are of comparatively little value. No clay suit- 

 able for the manufacture of anything but the coarsest earthenware has been 

 seen in any practical quantity. None of the clays are pure enough to make 

 a white ware. They are all too much stained with iron — a condition which 

 will render any ware such as jugs, jars, churns, etc., being glazed with the 

 "Albany slip" or some other black glaze. The Cass County clays may be 

 divided as follows: 



