64 GEOLOGY OF OHIO. 



It has also been sent out in thelarge way from the Zanesville district to North 

 Baltimore, Wood county, where a Cleveland company is engaged in the 

 manufacture of pressed brick. The clay here named furnishes a 1buff 

 brick of great beauty and excellence, natural gas being used as the fuel 

 for burning. 



In the Zanesville field the clay seam proper ranges from three to ten 

 feet in thickness, with a general average of six feet, but for thirty feet 

 below the limestone in many sections nothing but shale and clay are 

 found. It is generally divisible into an upper or plastic portion and a 

 lower and more silicious division. The seam is largely worked at Canton 

 in the manufacture of paving brick. A single analysis of it, as it is found 

 at North Industry, near Canton, gives the following result: 



(Stein and Schwartz.) 



Moisture, '. 6.45 



Combined Water, 5.41 



Silica 63.09 



Alumina, 20.17 



Oxide of Iron 2.12 



Alkalies 2.76 



The lower portion of the seam at the same point was analyzed by 

 itself, with the following result: 



Moisture '. 10.42 



Combined Water 12.72 



Silica, '. 41.15 



Alumina, 28.78 



Oxide of Iron 3,3g 



Alkalies, 3.55 ' 



This lower half of the seam is known as fire-clay, but the analysis 

 shows that it certainly cannot rank high in refractory qualities. 



This horizon must be counted as without doubt one of the valuable 

 clay deposits of the state. Its use has only been begun as yet. The areas 

 occupied by the seam in the district named are large and the exposures 

 in natural sections are abundant. It can be mined under cover to good 

 advantage, the limestone furnishing a strong and excellent roof for the 

 workings. A certain part of the seam in the vicinity of Zanesville is 

 highly esteemed as a source of refractory material. The Harris Fire 

 Brick Works, six miles above Zanesville, on the west side of the riven 

 make use of the lower part of the formation. The series found at this 

 point is as follows: 



Putnam Hill Limestone. 



Putnam Hill limestone shale, g jj f ee ^ 



White clay, ,' 4 to 5 ,. 



Dark clay 2 « 



Fire clay, o « 



Sandstone and sandy shale 5 <■ 



Brown clay, ■, 1 ,, 



