HARRISON COUNTY. 147 



siliceous clay, overlaid by a mottled red and blue sand and divided from the 

 overlying bed by a thin streak of ferruginous sandstone. This clay lies 

 among the red and white stratified sands and evidently belongs to the same 

 deposit. The following is a section of the cutting: 



1. Mottled red and blue sand 4 feet. 



2. White siliceous clay 2 feet. + 



The material found here may be utilized for the manufacture of a fair 



grade of fire bricks. These bricks will necessarily be confined to positions 

 in which comparatively low temperatures are held, such as household fire 

 grates or for boiler settings around cotton gins, grist and saw mills. It can 

 not be utilized for ware on account of its want of plasticity and generally 

 sandy nature. 



On the south side of the Peter Whetstone head right and about half a mile 

 south of the town of Marshall there is a deposit of blue sandy clay, which is 

 at present being used as a fire clay by the iron founders in Marshall for the 

 purpose of lining their cupolas, and is said to be very well adapted for the 

 work. The following is a section of the pit as it is open at present: 



1. Brown sand, unstratified and containing nodules of iron ore 4 feet. 



2. Blue sandy clay ' 3 feet. 



This blue clay is reported as being underlaid by a light colored yellowish 



white clay. The underlying bed is not visible in the present condition of 

 the pit, but about one-fourth of a mile nearer the town a whitish yellow 

 stained sandy clay is exposed in a deep cutting near the Firemen's Park, and 

 which, from its dip and elevation, may be the equivalent of the bed found at 

 the Adams pit. 



This clay bank is of considerable extent, and may probably be, with more 

 propriety, referred to the class of pottery clays. It is placed in this list from 

 the fact that it is at present being used for fire clay purposes. Although 

 used for cupola lining, it is extremely doubtful whether it will stand the ex- 

 treme heat necessary to be used in the manufacture of fire clay goods. In 

 the cupola it is used as a mortar in which to set the fire bricks forming the 

 main body of the lining, and as a thin wash spread over these bricks. It con- 

 sequently is not subjected in any body to the intense heat of the furnace. 



The following is an analysis of this clay dried at 115° C: 



Silica 71.00 



Alumina 20.20 



Iron ' 2.20 



Lime Trace. 



Magnesia Trace. 



Soda 6.16 



Potash , 1.24 



100.80 

 17 — geol, 



