t 
TRENTON LIMESTONE. 51 
every where else, and from finding it on the west side of the Noses, and in the same position 
on the west side of Little-Falls to the north of the river. 
The Trenton limestone has been uncovered to a considerable extent along the southwestern 
boundary of the primary. In Herkimer county, it covers a large portion of Norway, all but 
a fraction of Russia, and that part of Ohio which borders at the southwest on the two former 
towns. In Oneida county, it forms a continuous surface with Herkimer, and extends along 
the primary, averaging about three miles in brea'dth, and passing into Lewis county. Where 
it joins to Herkimer, its breadth increases, extending up to Stittsville and Holland patent, and 
into the valley of Beaver meadow as far as the mouth of Wells’ brook, where it disappears 
under the Utica slate, but soon reappears on the Mohawk, In Lewis county, it ranges nearly 
parallel with Black river, curving west in conformity to all the exposed rocks of that section. 
It forms a continuous mass in the three counties ; that is to say, in all its course there, its 
surface,- except on the south and west sides, is not covered by any other products than those 
of soil and alluvion. 
Where the rock is thin, the dark color prevails ; where it is thick, the lower parts retain 
the same kind of dark and thin layers, but the upper are often thick and of a light color. 
Layers of the latter kind occur in the valley at Holland patent and Stittsville, on the waters 
of Beaver meadow, at Trenton falls, along Cincinnati creek, and in numerous points where 
the Trenton limestone is exposed through Oneida and Lewis counties, but none were noticed 
so pure and solid as those of the first named places. 
Where the road which leads to Prospect leaves the one from Trenton village to Boonville, 
there is quite a novel exhibition, the water of the creek appearing in streams by the joints 
and other openings in the limestone which forms the bottom of the Cincinnati creek ; above 
the bridge, the water is seen entering the creek; -higher up, the whole stream is deserted, 
presenting a rock surface, under which, and by the joints of the rock, the water courses by its 
subterranean route to where it reappears near the bridge. 
From the facts here presented,, the origin of the Natural bridge in Virginia is readily under¬ 
stood. The bridge crosses a narrow deep limestone valley, like that of Trenton falls; the 
bridge being a part of the original rock which filled the valley, all the other parts having been 
removed by the same cause now acting in Cincinnati creek, and in the same manner. The 
rock there belongs to the same system, and is nearly of the same age with the trenton. The 
latter rock shows from one to three vertical joints; but in all rocks, the number varies in a 
given space : as a general rule, they are fewer where the layers are thickest. All, therefore, 
that it is necessary to conceive, in order that a bridge of the kind should be formed, is that 
water should flow as at the Cincinnati creek; that a part connected with the sides, and near 
the surface as in Virginia, should be more solid than the other parts where the water flows ; 
and finally, that all should be removed but the solid portion, leaving an excavation like that of 
Trenton falls. 
The grey limestone is quarried at Cincinnati creek as a marble, and burnt also for lime; 
it is also quarried in many places in Holland patent, Beaver meadow, &c. 
The vertical joints in the Trenton limestone are generally two in number. In Martinsburgh, 
