GEOLOGY OF THE PORT LEYDEN QUADRANGLE 57 



a more massive stone. The most extensive quarries are between 

 the mouth of Sugar river and Denley station. 



Other good building stone is found in the Trenton Hmestone, 

 especially the upper portion. This rock is gray, coarse grained, 

 crystalline, and pretty pure and may be quarried in layers from a 

 few inches to a foot thick. The stone is much used locally and 

 was formerly burnt in great quantities for the production of lime. 

 The chief quarries are at Talcottville, Turin and Martinsburg. The 

 sandstones of the upper Lorraine are strewn over the highlands on 

 the west and are of considerable local use. 



Of the Precambric rocks, the syenite is an excellent building 

 material. It is a very hard, greenish to reddish, rather granitic 

 syenite which takes a high polish. The expense of quarrying and 

 transportation have almost entirely prevented its exploitation. A 

 quarry from which syenite of fine quality has been taken is located 

 about a mile east of Denley station. 



Road materials 



Most of the Precambric rocks, but especially the syenite, because 

 of its great durability, when crushed would yield excellent road 

 materials. Most of the stone now used for road work comes from 

 the Lowville and upper Trenton limestones because this stone is 

 cheaply quarried and crushed and is fairly durable. 



Sand and gravel 



As above explained much of the country east of the river is 

 deeply covered with sand and gravel, often of good quality for all 

 sorts of uses. The increasing demand for such materials will, in 

 the future, doubtless cause the exploitation of these immense 

 deposits. 



Iron ore 



In the above descriptions of the Precambric rocks, magnetite, in 

 small grains, is seen to be very commonly present. Many times 

 patches of magnetite i or 2 inches across have been observed in 

 the mixed gneisses and in the more acid phases of the syenite and 

 they have every appearance of being segregation masses. An ore 

 body several feet across has been found on the Murtaugh farm 2 

 miles east of Glenfield. It is magnetite mixed with much pyrite 

 and is closely associated with pegmatitic material in the granitic 

 syenite. The pegmatite and ore seem to grade into the country 

 rock and probably represent a segregation mass. 



