208 THE MINERAL RESOURCES OF CECIL COUNTY 



A good example of this lower bluish clay is seen in the property 

 of Mr. Warren Grosh, on the Bacon Hill road about 3-J miles east 

 of the town of Northeast. The material is a blue plastic clay known 

 to be from 7 to 10 feet thick which lies below the level of the wagon 

 road. "With it there occurs some yellowish clay forming about one- 

 third of the whole mass. This is dug and shipped with the blue 

 material. The clay is sent to stoneware factories in Philadelphia. 

 A physical examination made by Professor Hies showed that 

 tempering this clay required 23 per cent of water and that the brick- 

 lets from it had an average shrinkage of 6 per cent. The average 

 tensile strength of the air-dried briquettes was found to be 111 pounds 

 per square inch. In burning incipient fusion occurred at cone 01 

 with a total shrinkage of 9 per cent, the color of the burnt clay being 

 cream white. At cone 02 the shrinkage was 10 per cent, at cone 

 4, 11 per cent, and at cone 5, 15 per cent. The clay was then nearly 

 vitrified and vitrification actually occurred at cone 8, with a total 

 shrinkage of 16 per cent. The chemical composition of this clay 

 is shown in the following analysis: 



Analysis of Stoneware Clay, Bacon Hill, Cecil County. 



Silica 65 . 70 



Alumina ■•••.... 20.30 



Ferric oxide 1 . 00 



Lime 3. 50 



Magnesia 1 . 44 



Alkalies 62 



Ignition 7.60 



Total 100.16 



Total fluxes 6 . 56 



Another important clay deposit is found along the shore at the 

 head of Beach Channel northwest of Carpenter Point on the prop- 

 erty of Mr. J. P. Simpcoe. At this point the bed is fully 20 feet 

 thick, but owing to the fact that it has not been worked extensively 

 the clay deposit does not appear prominently at the surface. Tests 

 were made upon this clay and the results may be summarized in the 

 statement that it probably is a stoneware clay but not a fire-clay, and 



