212 BULLETIN OF THE NEW YORK STATE MUSEUM 



and heavy masonry it Is well adapted. And it has been 

 employed extensively in the western part of the state. 



Lower Helderberg Limestones 



The Tentaculite, Water-lime and Pentamerus limestones 

 are included in this group. The outcrops are in the Ron- 

 dout valley, south-west from Kingston to the Delaware 

 river ; in the foot-hills east of the Catskills — in Ulster and 

 Greene counties ; 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 up- 

 per, are In thick beds and are gray, sub-crystalline in texture 

 and look 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 

 Schoharie valley, at Howes Cave, Cobleskill, Cherry Valley 

 and in Springfield. The quarries west of Catskill and In 

 Becraft's mountain near Hudson also are 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- 

 north-west and then west it continues across the state to 

 the Niagara river and Lake Erie. The subdivisions are 

 known as the Onondaga, the Corniferous 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 



