236 GEOLOGY OF OHIO 



of the colors produced is managed just the same as the grading of pressed 

 brick and ten or twelve shades are recognized. 



In actual quality, fine stock brick are apt to be of- a higher character 

 than press bricks which sell for more, on the principle that any clay- 

 ware that has been tempered in water is more cohesive and less absorb- 

 ent than dry press brick of equal hardness. 



Pressed Brick. The manufacture of high grade pressed bricks for 

 city buildings ani artistic architectural construction, has been slowly 

 developing for some years. It has received much stimulus in the last 

 few years and the industry is rapidly coming forward. Indeed the younger 

 generation of architects, and these same progressive manufacturers, are 

 rapidly making a new industry out of the old one. While there are a 

 number of pressed brick manufacturers, in Ohio, there are a comparatively 

 few who are representatives of the new departure. The Columbus 

 Brick and Terra-Cotta Co., The North Baltimore Pressed Brick Co., The 

 Akron Vitrified Pressed Brick Co., The Oakland Pressed Brick Co., of 

 Zanesville, and The Findlay Hydraulic Pressed Brick Co., are types of 

 the most progressive ones. Of these the last three named firms produce 

 nothing but fine red front bricks. The clays they use are different in 

 each case. The Akron Vitrified Pressed Brick Co., whose factory is at 

 Independence, is the only factory using the red Bedford shales, so far as is 

 known. These shales constitute a persistent but comparatively thin stratum, 

 which crosses the state in a line taking in Cleveland and Columbus. The 

 shales are always red in color. At Independence they form the top of 

 the hills and cover the surface down to the top courses of the Berea Grit 

 which is quarried extensively near by. 



Exposures as fortunate as this one, are likely to be rare, as the soft 

 shales are too easily eroded to form the surface deposit over any large 

 area. Hard rocks are usually lound ori the surface. The high grade of 

 this deposit is undoubtedly due in part to the mellowness which has been 

 imparted by centuries of exposure. 



The Oakland plant at Zanesville began operations on the famous red 

 loam which has made Zanesville stock brick famous in past years. After 

 some months of successful work they introduced a change in the compo- 

 sition by using one-half of the shales which cover the middle Kittanning 

 coal with the red loam. The change gave them no less choice a color, 

 together with far greater toughness and strength. The loam clay was 

 very sandy, and while it made a very beautiful brick it was a very tender 

 one and the edges were likely to be rubbed off and broken. The shale 

 is a fine paving brick material, and one which vitrifies easily; by mixing 

 it with the sandy clay, a bond by partial vitrification was produced. 



The Findlay Pressed Brick Co., use a surface drift clay of a very 

 sandy character, which they gather and shed during the summer season 

 with great care and by methods which insure thorough mixing and aver- 

 aging of the composition. 



