GEOLOGY OF THE NORTH CREEK QUADRANGLE 85 



Pottersville ; while the third is by the State road 334 miles north- 

 northeast of North Creek. 



The Grenville gneisses are nearly always of poor quality for 

 road work because of the high quartz and mica content and the 

 heterogeneity of the rocks which are in layers of varying com- 

 position. In spite of this, one quarry for State road purposes has 

 recently been operated near the southeastern end of Loon lake. 



BUILDING STONE 



There is an inexhaustible supply of building stone of excellent 

 quality within the map limits. The syenite, granite, and granite 

 porphyry all rank as very strong and durable building stones. Of 

 these the granite porphyry would perhaps make the most effective 

 and beautiful stone when highly polished because of the large, 

 scattering, pink, feldspar crystals which are set in the much finer 

 grained gray matrix. The color of this rock would remain practi- 

 cally unaltered on exposure to the weather. Some of this rock from 

 the quarry at Horicon is said to have been used in the State Capitol 

 at Albany. The pink granites, too, would make beautiful and very 

 durable building stones not subject to color change. The syenites, 

 which are generally greenish gray when fresh, would weather to 

 light brown on exposure to the atmosphere but, as regards dura- 

 bility and strength, they would be excellent stones. These igneous 

 rocks are considerably used locally but because of the distance 

 from population centers, no quarries have been opened up for ship- 

 ping purposes. The pinkish gray granite used in the construction 

 of the new Warrensburg High School building was obtained from 

 the south side of Hackensack mountain and just off the map. 



The only stone which has been quarried for shipping purposes 

 is the green marble or so-called verde antique of the Grenville 

 series. Though occurring at a number of localities, the only place 

 where quarrying has been done, and this years ago, is one-half of 

 a mile west-southwest of Thurman village. This rock is a medium 

 grained, white to greenish gray marble through which are scattered 

 many streaks and blotches of bright green serpentinous material, 

 so that the polished stone presents a striking effect. 



