GEOLOGY OF THE BROADALBIN QUADRANGLE 6 1 



terial, the chief objections are the heterogeneous character of the 

 material and the presence of so much mica which affects the bind- 

 ing power. 



BUILDING STONE 



Building stone of good quality is common throughout the Pre- 

 cambric areas, but the comparatively slight demand for such stone 

 has prevented any extensive exploitation. One and one-half miles 

 north-northeast of Northville a quarry has been opened in the 

 mixed gneisses. This rock, though called granite,' is really a Gren- 

 ville facies of the mixed gneisses. It is a gray, medium grained 

 rock, rich in feldspar, quartz, biotite, mica and garnet. The rock 

 takes a high polish and has been used in Northville especially for 

 tombstones in the cemetery on the north side of the village. 



Building stone of fine quality may be obtained from the Pots- 

 dam, especially where the sandstone beds are regular and the 

 cementing material is silica. There is a large quarry in such rock 

 on Bunker hill and the nearness to the railroad affords good ship- 

 ping facilities. Stone from the Trenton and Little Falls forma- 

 tions has been locally used to a small extent. 



LIMESTONE FOR QUICKLIME 



An excellent limestone used in the production of quicklime is 

 obtained from the Amsterdam formation. A number of quarries 

 have been opened and in nearly every case this heavy bedded, pure, 

 crystalline limestone just below the Trenton is preferred. The only 

 quarry and kiln now in operation within the map limits is three- 

 fourths of a mile east of Cranberry Creek. This is known as the 

 Kegg quarry. Mr Haines owns two quarries, one just off the 

 map and one and one-half miles north of Mayfield and now in 

 operation, while the other is two miles southwest of Cranberry 

 Creek and temporarily closed. 



Other quarries in the Amsterdam formerly worked are : In the 

 small area east of Mayfield ; on the west side of Bunker hill ; two 

 miles east of Broadalbin ; and one and three-fourth miles east of 

 Galway. 



On the Beecher farm, one and one-fourth miles north of North- 

 ampton, the Little Falls dolomite has been tried for quicklime. 

 This rock is said to make a lime which sets very hard but is ob- 

 jectionable because hot water is necessary for slaking. 



