436 



CLAYS AND CLAY INDUSTRY. 



phasize the fact that in this county there are five well-marked 

 groups of clay strata, separated by much thicker beds of sand. 

 These clay-bearing groups from the top downward are as follows : 



The Cliffwood lignitic clays; 



The Amboy stoneware clay; . 



The South Amboy fire clay ; 



The Woodbridge clay ; 



The Raritan fire and potter's clay. 



The position of these subdivisions, SO' far as it has been pos- 

 sible to- trace them in the field, is shown on Plate XI. Each of 

 them, as exposed in the clay banks, is capable of further division, 

 but these minor subdivisions are often extremely irregular, so 

 that neighboring sections are frequently unlike. Since, however, 

 any two successive layers often differ greatly in their physical 

 properties, the same pit may contain five or six grades of clay. 

 The following sections, which were taken from, pits not more than 

 500 feet apart, show something of this difference, although the 

 latter is more apparent than real, owing to the different names 

 applied to the same bed. 



Sections in adjoining clay banks at Woodbridge, showing variation in beds*. 



Locality 23. 



Woodbridge District. 



Known as Old Mellick Bank. 



Section made Sep., 1901. 



a. Drift 18 ft. 



b. Buff clay, 2 ft. 



c. Sand, 2 ft. 



d. Retort clay, No. 1, 



2 ft. 



e. Fire mortar, 4 ft. 



f. Black to steel-gray fire 



clay, 2 ft. 



g. No. 2 sandy clay, 2 ft. | 



h. Sand, 1 ft. f 



i. Fine clay, 1 ft. 



j. Stoneware clay, 4 ft. 



k. Black clay, 1 ft. 



Locality 24. 



Woodbridge District. 



H. Maurer & Son. 



Section made Sep., 1901. 



1. Drift, 4-IO ft- 



2. Pipkin clay, 2-5 ft. 



3. Sand with clay layers,. 3 ft- 



4. Blue "shorts" (alter- 



nating clay and sand) 4-5 ft- 



5. Yellow brick clay (a 



No. 2 fire clay),.... 2 ft. 



6. Yellow sand, 3 ft. 



7. Yellow top clay, 2 ft- 



8. Blue top clay (a light 



gray color) , 2 ft. 



9. Fire mortar, 3 ft- 



10. No. 2 sandy clay, .... 1 ft. 



11. Black sandy clay, ^ ft- 



12. No. 2 fire clay, 4-5 ft- 



13. Dark clay (rejected). 



