LIME AND CEMENT INDUSTRIES 823 



limestone ridge extending from Rondout to Saugerties and West 

 Camp. They are generally a mile or more from the shore of the 

 Hudson, but 2 miles north of Rondout approach close to it. The 

 Pentamems limestone has a thickness of 30 to 40 feet. 



Tentaculite limestone is generally a thin bedded, dark blue 

 limestone and forms the base of the Helderberg series. Its thick- 

 ness varies from 20 to 40 feet and is greatest about Rosendale. 



S'alina waterlime beds underlie the waterlime and are of consid- 

 erable importance, as they include the well known cement beds. 

 Darton says : " The usual characters of the formation are thin 

 bedded water limestones, and the cement is of local occurrence. " 

 It is a blue black, very fine grained, massively bedded deposit, 

 consisting of calcareous, magnesian and argillaceous materials in 

 somewhat variable proportions. 



The cement beds are extensively developed in the Rondout and 

 Rosendale regions. They come in gradually and are attended b;y 

 a thickening of the formatior from its usual average of 20 to 30 

 feet to 40 or 50 feet. At Rondout the principal cement bed has 

 a thickness averaging about 20 feet. It lies directly on the coral- 

 Hne (Niagara) limestone and is overlain by altering successions 

 of waterlime and thin, impure cement beds. The cement horizon 

 is not exposed far north of East Kingston, but how far it extends 

 to the northward is not known. It is seen to thicken southward, 

 and it attains its maximum thickness in the vicinity of Rondout, 

 thinning out again and giving place to waterlime beds south of 

 Wilbur. It is seen to have come up again in the Whiteport 

 anticlinal, which brings up a great development of cement bed» 

 along its principal axis from Whiteport to Rosendale. They 

 also come out along the western limb of the synclinal eastward. 

 South of Rosendale the cement beds continue up the Coxing kill 

 valley anf 1 around the point of the- anticlinal by Highfalls on the 

 Rondout creek. " Above this place it can be traced but a short 

 distance, owing to its deep erosion and heavy drift cover in the 

 Rondout creek valley." It reappears at Port Jackson. 



