y/. H. Winchell on a Great Primordial Q-uartzyte . 175 
Unlike, however, most of the sandstones, it is destitute of scales of mica. 
The coloring matter of the rock is evidently oxide of iron, but unequally 
diffused through it, giving it intensity or deepness of color in proportion 
to its quantity. In some places it is almost wanting, which makes it, 
>vhen pulverized, a good material for glass, The grains and particles in 
its composition are generally angular, but where it takes the character 
of a conglomerate, as it does in the inferior layers, they are frequently 
rounded. The thicker strata exhibit an obscurely striped appearance, 
owing to prevalence of certain colors in different layers. 
Two properties possessed by this sandstone increase essentially its value 
for all purposes to which it can be applied — its durability which is owing 
to its siliceous character, its evenness of grain and strata which facilitates 
and lessons the labor of quarrying and afterwards sa\''es the expehse of 
dressing preparatory to its employment as a building material. Both of 
these characters fit it admirably for every kind of use to which stone is 
ever required. As a firestone nothing can be found better, and if it is 
required for durable public works, as the locks of canals, etc., no material 
can be found better suited for the purpose. 
The strata of Racket river, where the principal quarries are opened, 
rise about 65 or 70 feet above the river. The quarries extend some ten 
miles along this river, which has apparently cut through the rock and 
exposed the strata on each side, dipping to the northwest at an angle of 
about 30 degrees. I have not ascertained the whole thickness of the 
beds. The layers vary in thickness from half an inch to four feet, so 
*hat every variety may be obtained; and the thicker strata may be split to 
any required thickness for which they may be wanted. Slabs having any 
superficial area w hich can be used, and of the given thickness, may be 
qiiarried with ease. The waters from which this sedimentary rock were 
formed, most have been in a perfectly tranquil state to have preserved 
such a regularity and evenness of surface and freedom from contortion. 
Such a state did not prevail everywhere, even in the immediate vicinity 
of Potsdam, for at DeKalb, in the same formation, there are some very 
remarkable contortions and disturbances. * * * ''•' It appears that 
when the strata were elevated they were frequently fractured for miles 
in a north and south direction, and along the line of the greatest uplift 
they were in one sense comminuted, or broken into small pieces. Sub- 
sequently currents of water passing over the whole region further broke 
up and carried away all the loose materials. The result of tlie combined 
effects of the uplift and of the currents has been the production of lom^ 
narrow valleys, bounded on both sides by perpendicular walls of sand- 
stone, which still stand, in many instances like regular mason work. 
The fracturt's usually extend down to the primary strata, and the whole 
stratum of ^nndslone has been sometimes removed to the gneiss and 
granite. 
That the above is not hypothetical is evident from the rounded corners 
of those portions of the strata which lie along these valleys and also from 
the scratches they received, and which still remain as perfect and fiesh 
