RAW MATERIAL: NATURAL-CEMENT ROCK. 



207 



New York. In the State of New York natural cement is now manu- 

 factured in four distinct localities. These are in order of importance: 

 (1) the Rosendale district in Ulster County, (2) the Akron-Buffalo dis- 

 trict in Erie County, (3) the Fayetteville-Manlius district, mostly in 

 Onondaga County, and (4) at Howe's Cave in Schoharie County. 



The clayey limestones used in these four districts occur in three 

 different but closely related geological formations, all in the Upper 

 Silurian group. The sequence and relation of these formations, from 

 the top downwards, is shown in the following table. 



For convenience these districts will be described not in the order 

 of their relative importance but in geographic order, from east to west. 



The Rosendale district lies entirely in Ulster County, the principal 

 cement-rock quarries being located at East Kingston, Rondout, Rosen- 

 dale, Binnewater, Lawrenceville, and High Falls. Two distinct beds 

 are worked at most of these points, differing in chemical composition 

 as well as in geological age. Darton states * that at Rosendale the 

 lower bed, or dark cement rock, averages about 21 feet in thickness, 

 and the upper, or light cement rock, about 11 feet, the two cement- 

 beds being here separated by 14 or 15 feet of worthless limestone. The 

 lower bed lies directly on the Clinton quartzite, the even upper surface 



* 13th Ann. Rept. N. Y. State Geologist, vol. 1, 1894, p. 334. 



