430 CLAYS AND CLAY INDUSTRY. 



Cone 5 : 



Fire shrinkage, ........ 74 % 10.00% 



Absorption, ..,,.., 8.26% H-33% 



Color, light red gray- 

 Condition, . steel-hard 



Cone 8 : 



Fire shrinkage,. ........ 8.7 % 9.4 % 11.6 % 



Absorption, 8.64% 3-7^% 



Color, cream white ...... gray 



At cone 15, No. I had a fire shrinkage of 11.7 per cent.; ab- 

 sorption, 1. 2 1 per cent., and it vitrified at cone 27. No. II 

 vitrified at cone 10; No. Ill was viscous at cone 30. 



A white clay of the composition given below was formerly 

 obtained by washing the clay found in A. C. Anderson & Com- 

 pany's pits two miles northeast of Trenton. Prof. Cook 1 gave 

 the following analysis : 



Analysis of clay. A. C. Anderson & Co., Trenton. 



Silica (Si0 2 ), 45-30 



Alumina (A1=0 3 ), 37-io 



Ferric oxide (Fe^C^), 1.30 



Lime (CaO), 0.17 



Magnesia (MgO), 0.22 



Titanic oxide (TiO^) , 140 



Water (H 2 0), 1340 



100.19 



Clays are also known to occur below Trenton along the bluff 

 bordering- the river, and northeast of the city near Clarksville 

 (p. 198). 



Clay Marls. 



Hightstoivu: — The most important openings made in the Clay 

 Marls are at B. H. Reed & Bro.'s brickyard near Hightstown 

 (Loc. 194), where pits have been dug along the boundary line 

 of Clay Marls I and II. The material obtained from these pits is 



1 1878 Rep. on Clays, p. 235. 



