428 NEW YORK STATE MUSEUM 



well when dressed. They are adapted to heavy masonry as well 

 as for cut work. 



Quarries are opened in this group of limestones in the Scho- 

 harie valley, at Howe's Cave, Cobleskill, Cherry Valley and in 

 Springfield. The quarries west of Catskill and in Becraft's 

 mountain, near Hudson, are also in it. 



Upper Helderberg Limestones. 



The Upper Helderberg formation appears in the Hudson valley 

 at Kingston ; thence it runs in a belt west of the river, to the 

 Helderberg mountains, bending to the west-northwest, and then 

 west it continues across the State to the Niagara River and Lake 

 Erie. The subdivisions are known as the Onondaga, the Cor- 

 niferous and the Seneca limestones. The first is more generally 

 recognized as the " Onondaga gray limestone " and the last as 

 the Seneca blue limestone. 



There is much diversity in the limestones of this group in 

 its long range of outcrop. The Onondaga gray stone is gray 

 in color, coarse crystalline; and makes beautiful ashlar work, 

 either as rock face or as fine tooled, decorative pieces. 



The Corniferous limestone is hard and durable, but it is so full 

 of chert that it can only be used for common wall work. 



The Seneca blue limestone is easily dressed and is a fairly 

 good building stone. 



Limestone of the Upper Helderberg epoch is quarried exten- 

 sively at Kingston, Ulster county, and is a valuable building stone. 

 In Onondaga county there are the well-known Splitrock and 

 Reservation groups of quarries, which have produced an immense 

 quantity of excellent and beautiful stone and which has found 

 a market in all of the central part of the State. They are in the 

 lower member of the group. Going west, there are the large 

 quarries in the Seneca limestone at Union Springs, Waterloo, 

 Seneca Falls and Auburn. The LeRoy, Williams ville, Buffalo 

 and Black Rock quarries are in the Corniferous limestone. 



The aggregate output of the quarries in. the Upper Helderberg 

 limestones exceeds in value that of any other limestone formation 

 in the State. The many quarries of the Trenton probably pro- 

 duce more stone. 



