CALCAKEOUS MARL. 253 



yard at Xorfolk, is the tirst plant built in the South to manufacture 

 Portland cement from shell marl as the principal calcareous material 

 used instead of the hard rock-limestone (Plate XIX, figs. 1 and 2). The 

 marl deposits are located on branches of the James Eiver near Smithfield and 

 Chuckatuck, about 25 miles from the plant. Eeported analyses of the 

 marls and clays used as a mix in the making of cement by this plant are as 

 follows : 



Analyses of marl and clay from the Norfolk Portland Cement Corporation s 

 property, near NorfolTc, Va. 



Constituents 



7.24 

 4.92 



Silica (SiO.) 



Alumina ( AI2O3 ) \ 



Ferric oxide ( Feo03) \ 



Lime (CaO) { 47.67 



Magnesia ( MgO ) j trace 



Marl 



Clay 



62.99 



23.45 



4.82 

 trace 



It is reported that previous to building the plant at Norfolk the material 

 from the Virginia marl deposits was shipped during the past 10 years to 

 the American Cement Company at Egypt, Penna., for the manufacture 

 of Portland cement. The cement made at N'orfolk is marketed under 

 the American Cement Company's established brand "Giant," a guarantee 

 that the new cement made from the Virginia Coastal Plain marls and 

 clays is in all respects the equal of that upon which the Pennsylvania 

 company has made its reputation. 



The company has built a line of railway extending from the large marl 

 and clay deposits which it controls, to a pier constructed for loading the 

 raw materials on barges of 500 tons capacity each, whence they are con- 

 veyed to the plant at Norfolk. Upon arrival at the plant the raw material? 

 are delivered from the barges into bins, by buckets having a capacity of 

 100 tons per hour, operated by two hoisting engines. The bin for marl 

 has a capacity of 500 tons and the one for clay a capacity of 100 tons. 



There are four kilns, each of 500 barrels capacity, with provisions for a 

 fifth. After burning to clinker and crushed, the finished product is carried by 

 screw conveyors to the stock houses of which there are two; one used 

 for storing cement shipped by rail and the other on the loading wharf for 

 storing cement to be shipped by water. The plant, covering four and 

 one-half acres, is a large and commodious one, entirely modern and is 

 fully equipped with the necessary machinery, etc. (Plate XVIII). 



