TRENTON LIMESTONE. 
53 
exceed a foot in thickness, are usually from four to six or ten inches, and separated by more 
or less shale, the whole of a dark or black color. The layers dip at a very perceptible angle 
with the stream, the course of which is a little to the west of south, some of the layers appear¬ 
ing to play more than one part at the falls. 
There can be no doubt that the whole of this passage has been caused by the action of 
water and frost, no trace of a fault being visible in any part of its course, which could rea¬ 
dily be perceived at the mill where the excavation ends, or at any of the falls, when the 
water is low, if any existed. There are evidences of local disturbances, but they are trifling 
in comparison with the vast mass of the rock in which nothing of the kind exists. The great 
facility afforded to the water of the creek in making this channel, was the double system of 
joints in the rock at nearly right angles to each other, and the shale which usually separates 
its layers. There is a third system of joints, but it is a partial one. It is by operating upon 
these joints, of which few rocks are destitute, that water and frost are enabled to exert their 
great power. Though the quantity of water which passes by the falls be very considerable, 
it must be small in comparison with the volume or body which once had its outlet in that 
direction; so prodigiously great is the amount of alluvion which is heaped upon the surface 
of the rock, facing its banks above Prospect, and from that village, to Trenton village. 
There are some very limited local disturbances to be seen near the “ Great falls,” which 
merit notice. The first is on the west side, and below the falls. For thirty or more feet in 
6 . 
length, and from three to five feet in thickness, the rock exhibits extraordinary contortions for 
one whose layers are so regularly disposed, forming almost semicircular curvatures, and not 
unlike the writhings of a huge serpent. Though the disturbance is so great within the limits 
given, yet the layers above and below are wholly unaffected by it. When the contortions are 
examined, they show a crystallized white limestone, enveloped in the usual calcareous shaly 
materials, proving that the disturbance was caused by the crystallization of the white lime¬ 
stone forming a layer ; which, for want of room to expand, this effect being simultaneous with 
the action as in the freezing of water, was forced to recoil, and thus to form the contortions 
noticed. It is not unlikely that the water of the mud from whence the shale was produced, 
was the solvent of the calcareous particles, enabling them to assume the crystalline state. At 
one of the extremities of the contorted rock, where it joins the undisturbed portion, it is broken 
into fragments, some of which are turned on end from the violence of the action. 
