356 CLAYS AND CLAY INDUSTRY. 



layers seem to yield a fine-grained, fairly homogeneous product, 

 which, when washed, might be used in the manufacture of dry- 

 pressed floor tile, and preliminary experiments made on some 

 have yielded favorable results. 



In some of the banks, layers are occasionally found which in 

 their natural condition are sufficiently plastic and homogeneous 

 for the manufacture O'f earthenware, but they have not been 

 utilized for this purpose, and in fact the available quantity seen 

 at any one locality would be sufficient only to< supply a small 

 pottery. 



CLAY MARL IV. 



Clays from this member of the Clay Marl series are not as yet 

 commercially important, and, so i far as observed, are not suitable 

 for much else than common brick. Just west of Mount Holly 

 (Loc. 123) a loamy surface clay, which is perhaps the weathered 

 portion of this bed, or more likely is a Pleistocene deposit is 

 utilized intermittently for common brick. 



A sample of Clay Marl IV was collected for testing from the 

 railroad cut near Bellmawr station (Loc. 148), on the P. & R. 

 railroad, and 1 mile south of Mt. Ephraim. The clay from this 

 locality is of yellowish color when fresh and of sandy texture 

 with scattered mica scales. Owing to its sandy character it 

 slakes rapidly. The material, in its color-burning qualities, is as 

 good as the best of the samples from Clay Marls I and II, burn- 

 ing to a brick red of uniform tint. It required 20.8 per cent, 

 water in mixing, and had an air shrinkag'e of 9 per cent, with 

 an average tensile strength of 195 lbs. per square inch. Its be- 

 havior in burning is shown below : 



Burning tests on a Clay Marl IV. 



Cones. 03 1 3 3 10 

 Fire shrinkage, ... 3 % 3 % 3-5 % 4-3% Viscous 

 Absorption, 14-55% 12.71% 12.06% 



It is by no means a refractory clay. 



