CLAY-BEARING FORMATIONS. 355 



Some improvement was shown when the bricklets were burned to 

 cone 1, but it was not marked except in the case of one sample 

 from Asbury Park (Loc. 217, Lab. No. 697). The light- 

 colored sandy clays remained quite porous even when fired to 

 cone 10. 



Variations in the same bank. — The bank of Asbury clay ex- 

 posed in Drummond Brothers' brickyard at Asbury Park, forms 

 an excellent example of the dissimilarity of three beds in the 

 same section. The top layer is a loamy clay. (Lab. No. 658.) 

 The second layer consists of a light-colored, gritty clay, made 

 up of alternating fine layers of sand and clay. (Lab. No. 697.) 

 The third is a black, micaceous clay, rather dense, but with thin 

 layers or laminae of sand every few inches. (Lab. No. 696.) 

 A mixture of equal parts of the three is used for making stiff- 

 mud brick. If, however, a mixture of equal parts of 696 and 

 697 is used, the effect is interesting, as shown by No. 4 of the 

 following table : 



For purposes of comparison the physical characters of the three 

 clays alone, as well as the mixture of two layers, are given below : 



Physical characters of clays from Drummond 's clay pit, Asbury Park. 



1st layer. 

 Water required to temper, .... 20.9% 



Air shrinkage, 3-3% 



Average tensile strength, lbs. 



per square inch, 107 



Fire shrinkage at cone 05, 



Fire shrinkage at cone 1, 



The water required for a mixture of No. 2 and No. 3 is much 

 less than for No. 3. The air shrinkage has not been decreased 

 below that of No. 2, but the most curious effect perhaps is the 

 increase in tensile strength to a point considerably above that of 

 No. 3 ; the fire shrinkage at cone 05 has been diminished. 



Uses. — Up to the present time the Asbury clays have been used 

 only for making common brick, the clays being dug 1) near 

 Asbury Park, 2) on the N. J. Southern R. R., southwest of Pine 

 Brook, and 3) near Howell Station. Some of the lighter sandy 







Mixture of 2d 



2d layer. 



3d layer. 



and 3d layers. 



27 % 



37-3% 



31-2% 



6.3% 



5-6% 



6.3% 



137 



182 



258 



0.4% 



3-3% 



0.3% 



1. % 



7- % 



2.2% 



