MARYLAND GEOLOGICAL SURVEY 207 



articles, together with their fine exposure in the cuts made by the 

 Bay render them possible sites for brick-yards and clay-working estab- 

 lishments. The more valuable clays are situated a short distance 

 from the shore-line but within easy haul of landings. Samples of 

 the chocolate-colored clay exposed in the embankments along the 

 highway 3-J miles south of Northeast on the way to Elk Neck show a 

 very fair plasticity. The degree of fineness can be estimated roughly 

 from the fact that more than 90 per cent of the material passed 

 through a sieve of 150 meshes to the inch. Tests made from the 

 samples showed the clay to possess the following properties: It re- 

 quired 20 per cent of water to mix it to proper plasticity and the 

 bricklets made had an air-shrinkage of 5 per cent and an average 

 tensile strength of 100 pounds per square inch. At cone 5, which is 

 about the temperature reached in some common brick kilns, the clay 

 burned to a buff color but could still be scratched with a knife. 1 

 Other exposures of brick-clay occur on the old " Neck Road " about 

 three miles south of Elkton and just north of Plum Creek; in 

 Thompson's gulley, where there is an exposure of a bed of at least 

 20 feet thick; and about two and a half miles south of Northeast on 

 the shores of Northeast River. 



In the areas to the southeast of Elk Neck and northward from the 

 Baltimore and Ohio Railroad there are at present no plants manu- 

 facturing brick or terra cotta. There is, however, an idle plant at 

 Welsh Point which was erected for the grinding, cleaning and drying 

 of clay for shipment. The clay used occurs in two beds, namely, 

 an upper and a lower blue, the latter lying for the most part below 

 tide-level. 



STONEWARE CLAYS. 



The localities for stoneware clay along the railroad are almost the 

 same as those enumerated for brick- and terra cotta clay. The best 

 clays for this purpose come from near the base of the Patapsco for- 

 mation but there is often a deposit of bluish-gray plastic clay lying 

 just beneath the variegated clays. 



1 Additional details may be gained by reference to the Report on the Clays of 

 Maryland, by Heinrich Ries. 



