LIMESTONE AND MARBLE 427 



are both represented. Many quarries have been opened in the 

 formation and there are many more localities where stone has 

 been taken from outcropping ledges, which are not developed 

 into quarries proper. The more important localities which are 

 worked steadily are : Glens Falls, Amsterdam, Tribes Hill, Cana- 

 joharie, Palatine Bridge and Prospect in the valley of the 

 Mohawk ; and Lowville, Watertown, Three Mile Bay, Chaumont 

 and Ogdensburg in the Black River and St. Lawrence valleys. 

 The railroad and canal lines, which traverse the territory occu- 

 pied by these formations, afford transportation facilities and 

 offer inducements to those who are seeking new quarry sites 

 where these limestones may be found in workable extent. 



Niagara Limestone. 



The Niagara limestone formation is well developed west from 

 Rochester to the Niagara river ; and there are large quarries in 

 it at Rochester, at Lockport and at Niagara Falls. The gray, 

 sub-crystalline stone in thick beds is quarried for building pur- 

 poses. It is filled with encrinital and coralline fossils and. the un- 

 equal weathering of the matrix and the fossiliferous portions are 

 sometimes such as to give the dressed surface a pitted appearance 

 with cavities which roughen and disfigure it. For founda- 

 tions and heavy masonry it is well adapted. It has been exten- 

 sively employed in the western part of the State. 



Lower Helderberg Limestones. 



The "Water-lime, Tentaculite and Pentamerus limestones are 

 included in this group. The outcrops are in the Rondout valley, 

 southwest from Kingston to- the Delaware river ; in the foot- 

 hills east of the Catskills — in Ulster and Greene counties ; on 

 Becraft's mountain, near Hudson ; and in a belt stretching west 

 from the Hudson valley, along the Helderbergs and across 

 Schoharie into Herkimer county. 



The Tentaculite limestone is dark-colored, compact and in 

 thick beds and can be quarried in large blocks. Some of it can 

 be polished and makes a beautiful black marble, as for example, 

 that of Schoharie. 



The Pentamerus limestones, both the lower and the upper, are 

 in thiok beds and are gray, sub-crystalline in texture, and look 



