i eckel. J NEW YORK. 267 
Bullock buhrstone mill, which grinds to about 16 mesh. It is then 
weighed and mixed with the wet marl as both are shoveled into the 
(chutes leading to the revolving mixer. The mixture then goes to the 
ypug mills and is made into bricks, which are sent to the drying tun- 
[nels. The lower tier of these tunnels is heated by direct heat, on the 
jCummer system; the upper tier by exhaust steam. Sixteen dome 
■kilns are in use. From the kilns the clinker goes to an 18 by 30 inch 
I Blake crusher; then to dry pans, receiving its final reduction in 
Sturtevant rock emery mills. The product is marketed as the Genesee 
Way land brand. 
Two firms in New York State manufacture, in addition to their nat- 
jural cements, brands which are marketed as " natural Portlands." The 
jlimestone is fed, without previous grinding or admixture, direct to 
I the kilns. As the limestone used carries, as shown by analyses of 
Itheir natural cements, an amount of magnesia (over 8 per cent in the 
(finished product), at present considered inadmissible in a Portland, 
the value of the resulting cements is problematical. From laboratory 
tests it would seem that they can usually pass all Portland require- 
ments, though rather low in tensile strength on short-time tests. 
[Concerning the qualities which they develop when used in actual work, 
(no information has been obtained; but the cements can not be worse 
than some of the poorer foreign Portlands which are unloaded upon 
the American market. Cements of this type can, of course, be placed 
upon the market profitably at a price only slightly above that of 
"natural" cements, the only additional cost being due to a little extra 
expense in grinding the clinker. 
PORTLAND-CEMENT RESOURCES OF NORTH CAROLINA. 
No cement plants have ever been operated in North Carolina, and 
the State will probably never be an important cement producer, because 
of the conditions as to fuel and the lack of local markets. If com- 
mercial conditions should justify the erection of a cement plant, how- 
ever, good raw materials are available. 
The limestones suitable for cement manufacture in North Carolina 
fall into two classes, distinct geographically as well as geologically. 
There are (1) the crystalline limestones of western North Carolina; 
(2) the soft limestones of eastern North Carolina. 
CRYSTALLINE LIMESTONES. 
In the extensive area of metamorphic and igneous rocks, that covers 
the western half of North Carolina, outcrops and beds of crystalline 
limestones or marbles are common. Many of these marbles are highly 
* magnesian in composition, but the specimens used for the analyses 
given below were low in magnesia. 
