42 NEW YORK STATE MUSEUM 



northern New York and the proximate section of New England. 

 Trenton limestone and local clays are employed in the mill. 



In central New York the Cayuga Lake Cement Corporation and 

 the Millen Portland Cement Co., have been the only producers in 

 recent years. The former operates a mill on Portland Point, 5 miles 

 north of Ithaca, where the Tully limestone outcrops near the lakeside. 

 Cayuga lake is connected with the canal system of the State and 

 shipments are made both by water and rail. The Millen Portland 

 Cement Co., erected a plant at Jamesville, Onondaga county in 1913, 

 the last one to be built in the State. The supply of limestone is 

 secured from the quarries of the Solvay Process Co. nearby, the 

 smaller stone being employed for cement. The beds include the 

 Manlius, Coeymans and lower part of the Onondaga formations. 



All of the marl plants that were built in the central part of the 

 State have been destroyed or dismantled, resulting in the loss of 

 considerable manufacturing capacity in this section. The last of 

 the mills to succumb was that of the Marengo Portland Cement 

 Co., near Caledonia, Livingston county, which was dismantled in 

 1912. 



NATURAL CEMENT 



Cement rock supplies. The materials that have been used for 

 natural hydraulic cement are impure limestones which occur in 

 various formations of the Silurian system. They have a consider- 

 able content of clayey matter and also are usually rather high in 

 magnesia in which respect they differ most markedly from the port- 

 land cement limestones. In the Rosendale district of Ulster county, 

 the cement rock contains from 54 to 75 per cent of calcium and 

 magnesium carbonates and from 20 to 40 per cent or so of combined 

 silica, alumina and iron oxides. In central New York the typical 

 rock runs higher in carbonates of which it contains 80 per cent or 

 more, with 15 to 20 per cent of argillaceous impurities. 



The natural cement industry had its principal center in the 

 vicinity of Kingston, the several quarry localities including East 

 Kingston, Rondout, Binnewater, Lawrenceville and Rosendale. 

 The beds suitable for cement making are found in the Salina and 

 Rondout formations and measure up to 50 feet thick. They are 

 usually tilted at high angles, so that many of the excavations are 

 really underground mines in which the rock is taken out in large 

 rooms, with pillars left at intervals for support of the roof. The 

 mines have been worked to depths of 800 to 1000 feet on the slope 

 and 1000 feet or more along the strike. Van Ingen and Clark^ made 



^ Disturbed fossiliferous rocks in the vicinity of Rondout, N. Y. N. Y. State 

 Mus. Bui. 69, 1903, p. 1 176-1227. 



