196 [Assembly 



lY. 



Sandstones or Freestones, and their Varieties ; their Geologi- 

 cal Position axd Geographical Distribution within the 

 State of New York. 



1. The Potsdam sandstone formatioij is the lowest member of 

 the unaltered stratified rocks. The formation consists of numerous 

 beds of varying thickness, and of a gray, white, buff or red color. 

 The rock is naturally fine-grained and compact, and in many local- 

 ities furnishes a strong durable material. The beds are usually thin, 

 but generally sufficiently thick for the ordinary purposes of con- 

 fitruction. 



In its eastern extension, this formation occupies a considerable 

 area in Washington county, and is especially 'conspicuous in the 

 neighborhood of Whitehall. It occurs at numerous places along 

 the west side of Lake Champlain, and is especially developed in the 

 neighborhood of Keeseville. In some parts of Clinton county the 

 rock is too friable for any economical use beyond furnishing sand 

 for glass-making. In Franklin county, at Malone, the rock has been 

 extensively quarried and used for building and flagging stones for 

 man}' years past. At Potsdam, and other places in St. Lawrence 

 county, the stone is of a reddish brown color, close-grained and 

 compact in texture. The rock continues of similar character in 

 Jefferson county on the north side of the Black river vallej'. Its 

 commonly striped or variegated color offers an objectionable feature 

 for general use in building. 



2. Sa-ndstones and argillaceous sandstones of the Quebec and 

 Hudson river groups. Certain parts of both of these groups of 

 rocks furnish building stones of greater or less value. The greater 

 part of the stone known as hlue stone (the Maiden hlue stone 

 belongs to a different formation and has a different character}, along 

 the Hudson and Mohawk valleys is derived from one or other of 

 these formations. The higher beds of the Hudson river group have 

 also been quarried in Oneida, Oswego and Lewis counties, but they 

 are not extensively used. 



The quarries along the Mohawk river below Schenectady have fur- 

 nished a large quantity of this blue stone, for foundations, water 

 tables, and for entire buildings. Where the strata are but little 

 disturbed and lie nearly horizontally, the beds are easily worked, 

 and the blocks are readily dressed. The rock can be quarried in 

 regular masses and of any required dimensions. In the valley of 

 the Hudson, the rock is so much disturbed that the strata are broken, 

 and do not readily afford the means of furnishing large qunntities 

 of regular formed blocks for masonry. Nevertheless they are 

 largely used for foundation stone, and many thousands of tons are 

 annually quarried along the river. At and below Poughkeepsie, 

 the stone of this character, quarried along the river, is of the Quebec 

 group. The strata all consist of an argillaceous sandstone, very 

 compact and strong, but breaking irregularly. Those which break 

 into large masses are very strong, and make excellent foundation 

 stoues ; but I believe none of the beds are used for dressed stone. 



