CLAYS OF MIDDLESEX COUNTY. 453 



wise a soft, fine-grained clay, which slaked slowly. It worked up 

 with 40 per cent, of water, and had an air shrinkage o<f 5 per 

 cent., but its tensile strength was low and all the briquettes devel- 

 oped cracks in drying. It behaved as follows when burned : 



Burning tests of washed ball clay. J. R. Such, Burt Creek. 

 Cone 5 82? 



Fire shrinkage, 9% 12% 



Absorption, 16.42% 10.20% vitrified 



Color, white with yellow tinge yellowish white gray 



Stoneware Clay. 



This term is used chiefly in the area around Woodbridge 

 and South Amboy, and refers to beds of fire clay, of No. 

 2 grade, good plasticity, and dense-burning qualities. On 

 account of the two last mentioned qualities they are specially 

 adapted for the manufacture of stoneware. They can therefore 

 be called a variety of No. 2 fire clay. In some pits two grades of 

 stoneware clay are recognized. Those dug in the Woodbridge 

 area are found in the Woodbridge fire-clay bed, and those on the 

 south side of the Raritan river occur in the Amboy stoneware-clay 

 bed. 



Woodbridge. — In the Woodbridge district a sample of stone- 

 ware clay from the eastern pit of W. H. Cutter (Loc. 29) was 

 tested. 



For purposes of identification the section carrying the stone- 

 ware clay' is given below : 



Section of W. H. Cutter's clay bank, Woodbridge. 



1. Drift. 



2. Hollow-brick clay. 



3. Buff clay, for terra cotta and saggers, 4 ft. 



4. Gray sand, 1 Yz 



5. Rockingham clay, used for fancy brick, 1Y2 



6. Gray-black sand and clay, 4 



7. Stoneware clay, 1 



8. Top-sandy clay, 2Y2. 



9. Black clay, 1-2 



10. Sand, 4 in.-2 



11. Retort clay, for stoneware and saggers, 4-5 



12. Bottom-sandy clay, 2-3 



13. Fine fire clay, \ „ 



14. Ball or ware clay, J 



15. Red-mottled clay. 



