CLAYS OF BURLINGTON COUNTY. 387 



lower foot was distinctly marly (Clay Marl I), and near the bot- 

 tom there was also evidence of iron oxide crusts. A bank near by 

 showed 20 feet of chocolate-colored clay, Clay Marl II. The de- 

 posit is well located for working and the haulage distance to the 

 wagon road is not more than 500 feet. The stripping of Pen- 

 sauken sand and gravel will probably not exceed 6 feet. 



Clay Marl IV, or a surface clay derived from it, is worked at 

 two localities in Burlington county. It is dug in two clay pits just 

 north of Timbuctoo* (Loc. 123) (PI. XV, Fig. 2) and 1V2 

 miles northwest of Northampton, and supplies two small brick- 

 yards. When molded by hand and burned in scove kilns, it makes 

 a porous brick. Harder burning would improve it. 



Another exposure is found 2 miles due east of Rancocas, on a 

 •stream 200 feet south of a small bridge, and just before reaching 

 the farm house on M. Hayne's property (Loc. 124). The bed is 

 4 feet thick, underlain by coarse sand and overlain by 1 2 to 1 5 feet 

 of loam and gravel. It is of low plasticity, coarse-grained and 

 sandy. Unless the bed thickens, when dug into, it would have no 

 value. 



In addition to the above localities, from which samples were 

 taken, the Clay Marls are known to outcrop at many other points 

 in the county, the following localities being shown on map 

 Plate Xa. 



Black's creek. — Both I and II are frequently exposed along the 

 banks of Black's creek and its tributaries, particularly in the steep- 

 sided ravines. At locality in, just south of Bordentown, the 

 sandy clays of the Raritan are exposed near the creek, overlain hy 

 60 feet of green-black, sandy clay, becoming more chocolate col- 

 ored in some higher beds, and all belonging to Clay Marl I. At 

 the top of the bluff, in an old clay pit, the bottom layers of Clay 

 Marl II, a chocolate-colored, nonglauconitic clay are found. The 

 overburden is not heavy and the bank could be easily worked, al- 

 though the material is somewhat sandy. 



Other good exposures occur near Mansfield Square both along 

 Black's creek and also along the brook west of Mansfield Square. 



Kinkora to Columbus. — So, too, the Clay Marl beds are ex- 

 posed along the creek northwest of Columbus. At locality 117, 

 2y 2 miles from Columbus, a sandy black, micaceous clay with 



