CLAYS OF CAMDEN COUNTY. 397 



At cone 1 the bricklet shows small fused specks, probably of 

 glauconite, and at cone 8 it becomes viscous. This easy fusibility is 

 probably due to a considerable amount of greensand. Its fire 

 shrinkage is low, and so' is the absorption. 



Analysis of clay from railroad cut near Merchantville. 



Silica ( SiOO , 67.02 



Alumina (AI2O3), 17.10 



Ferric oxide (Fe 2 3 ), 4.41 



Lime (CaO), 0.93 



Magnesia (MgO) , 0.38 



Alkalies (Na.O, K,0), 1.60 



Water (H=0), 8.56 



100.00 



Cooperstozi'ii. — On the road to Stockton, 2}^ miles southeast of 

 Cooperstown, there is also' an exposure of Clay Marl I (Loc. 

 142). The deposit was bored to a depth of 4 feet, and found to 

 be weathered in its upper part. A sample (Lab. No. 604) taken 

 for partial physical test gave the following results : Water re- 

 quired, 25 per cent. ; air shrinkage, 6 per cent. ; tensile strength 

 not tested. 



Burning tests of clay from southeast of Cooper ■stown (Loc. 142). 



Cone 05-07 / 



Fire shrinkage, 1% 4% 3.6 % 



Absorption, 22.61% 16.07% 15-85% 



Color, red red 



Condition, not steel-hard nearly steel-hard steel-hard 



It is seen from this that the clay burns to a very porous body, 

 is not' hard until probably cone 1 , and has a low fire shrinkage. 

 The color in burning is good, however. A more plastic clay 

 should be mixed with it. 



Clay Marl II. 



Collingswood. — Clay Marl II is well exposed in Dobb's brick- 

 yard pits (PI. XVIII, Fig. 1), 1 mile south of Collingswood 

 (Loc. 144). Here the outcrop is worked in a face 12 to- 15 feet 



