CHAPTER XVHI. 



ECONOMIC DESCRIPTION OF THE 

 CLAY-BEARING FORMATIONS, 



CONTENTS. 



Post-Pleistocene and Pleistocene. 



Cohansey clays. 



Alloway clay. 



Asbury clay. 



Clay Marl IV. 



Clay Marl III. 



Clay Marl II. 



Clay Marl I. 



Raritan clays. 



Triassic shales. 



Hudson shales. 



The extent, thickness and distribution of the clay-bearing 

 formations of New Jersey have been described in detail in Part 

 II of the present report, so that in this chapter only a brief 

 summary of their economic characters will be given, leaving* the 

 detailed discussion of the individual occurrences to be taken up 

 in the county descriptions which follow. At the end of the 

 description of each formation, in the present chapter, there is 

 given a table containing all the determinations of water absorption 

 in mixing, air shrinkage, tensile strength, fire shrinkage and 

 absorption of burned bricklets that have been made. 



PLEISTOCENE AND RECENT CLAYS. 



Twenty-one samples of Pleistocene and post-Pleistocene clays 

 have been examined in the laboratory. Those from the northern 

 part of the State were deposited in connection with the melting 

 ice of the last Glacial epoch or have resulted from: wash at the 



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