GEOLOGY OF THE VICINITY OP LITTLE FALLS 83 



Much of the pre-Cambrian rock to the north would also serve 

 the purpose well. The syenite gneiss is best, while the red granite 

 gneiss and the light colored, Grenville quartz gneisses are not well 

 adapted and should not be used. 



Next to the pre-Cambrian rocks the black, slaty limestones of 

 the passage beds afford the best road material, and have already 

 been somewhat used for the purpose in the district. The main 

 objection to their use is expense in quarrying, since the shale 

 partings must be rejected, and these constitute half the bulk of 

 the rock. 



Both the Lowville and Trenton limestones will furnish an 

 acceptable road metal, the former .better than the latter. The 

 Beekmantown rocks are in general too sandy, and much inferior 

 to any of the foregoing. 



The advantage of the pre-Cambrian rocks over the limestones 

 is in their superior durability, along with sufficiently good bind- 

 ing power. But the work must be done with much more care 

 in order to produce satisfactory results, and where this can not 

 be done, the limestone is the preferable material. 



Clays. Use has been made of the clays in but one locality, A. C. 

 Kayser manufacturing brick from a clay bed just out of Dolge- 

 ville to the west. 1 There would seem no good reason why an 

 excellent quality of common brick, and tile also, should not be 

 manufactured from the laminated clays in several localities, pro- 

 vided exploitation shows the clay present in sufficient quantity, 

 as is in all likelihood the case. 



Sand and gravel. There is a great abundance of both these 

 materials for all possible uses, both in the Mohawk valley and 

 also along the line of the great moraine which follows rather 

 closely the pre-Cambrian boundary. 



Salisbury iron mine. The only locality within the sheet limits 



at which iron ore has been found in anything like workable 



quantity, is at the above mine, 2 miles north of Salisbury Center. 



Considerable ore has been obtained at this location, some quite 



'Hies, H. N. Y. State Mus. Bui. 35, p.713. 



