TRENTON LIMESTONE. 



53 



exceed a foot in tliickness, 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 

 facihty 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 -yvhich 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 



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 hmits 

 given, yet the layers above and below are wholly unaflected by it. When the contortions are 

 examined, they show a crystalhzed 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 td 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 watei: of the mud from whence the sliale 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. 



