448 NEW YORK STATE MUSEUM 



in which the stone shows crevices and holes, due to unequal 

 weathering of coralline masses and of the more fossiliferous 

 portion. The improper position of the stone in the walls (more 

 than 40 per cent, being set on edge) may explain the serious 

 defects seen in this example. 



West of Lockport the Niagara limestone is quarried at Niagara 

 Falls, for building in the town. Across the river, on the Cana- 

 dian side, the same formation near Queenstown, furnishes some 

 stone to Buffalo which is in much favor with some architects and 

 builders. 



Road Metal. 



By Heinrich Ries ; Revised bf F. J. H. Merrill. 



The rocks used for road metal in New York State are diabase 

 (trap.), granite, gneiss, limestone, sandstone, shale and gravel. 



Many of the local stone quarries, which are scattered over the 

 State, sell for road metal the rock obtained in stripping off the 

 upper layers from their quarries. 



There are a few large quarries which are operated for obtain- 

 ing road metal alone and which deserve special mention. 



Many tons of material are quarried annually from the Pali- 

 sades range near Piermont. The material, which is exceedingly 

 tough, is either dressed for paving blocks or crushed for road 

 metal. 



Farther up the Hudson river the limestone quarries of Tomkins 

 Cove have been in operation for a number of years and supply 

 large quantities of rock for macadam. It is one of the best 

 materials used. This magnesian limestone is hard and packs 

 easily and makes a good surface, but the cost of maintenance is 

 considerable. 



The following is an analysis of the Tomkins Cove Rock : 



Lime 60 .20 



Alumina 11.22 



Silica 6.13 



Magnesia 10 . 45 



Carbonic acid 8 . 



Water 4 . 



100. 



