822 n:ew yobk state museum 



Extensive quarries have been opened in it near Hondout, Ed- 

 dyville and Whiteport. The lime made from it is of good quality, 

 Inmpy but slightly brown in color. The Becraft limestone ex- 

 tends across the eastern portion of the county from north to south. 

 It is well exposed between Saugerties and Rondout and about 

 "Wilbur and Whiteport, but exposures of it are rare southwest 

 of this latter locality except at Mill Hook and Highfalls. 



Samples for analysis were collected from the quarry of the 

 Newark cement co. at Rondout, and the average of these gave: 



Silica 3 . 87 



Ferric oxid 1 . 34 



Alumina 1.07 



Lime 54 . 11 



Magnesia tr. 



Carbon dioxid 40 . 6 



100.99 



Another set of samples from the quarry of B. Turner near 

 Wilbur gave: 



Silica 7.1 



Alumina 2.5 



Ferric oxid 1.65 



Lime 45 . 22 



Magnesia. . . tr. 



Carbon dioxid 39.1 



95.57 



The Pentamerus limestone member of the LoAver Helderberg 

 in Ulster county, is a hard, dark blue or lead colored, massive 

 limestone. 'Not infrequently it is somewhat cherty. Its hard 

 and tough character frequently causes it to give rise to cliffs. 

 Good exposures of this rock occur in the cliffs at Rosendale, about 

 Port Jackson, near Eddyville and along the eastern face of the 



