SUPERFICIAL GEOLOGY OF DTJNDAS VALLEY. 109 



band of broken material containing considerable quantities of chert.* 

 The talus, of which there is only a moderate quantity, is largely com- 

 posed of pieces of this broken band, and can be seen in the ravine, 

 or channel, formed by every brook flowing over the escarpment, 

 The section given by Sir Wm. Logan, in his Geology of Canada, % 

 places the Niagara beds in the vicinity of Hamilton, at fifty-eight 

 feet, three inches in thickness. This section, beginning at the 

 pentamerus bed, gives five beds ; three of limestone, aud two of 

 shale. The other twenty feet of this section will be found, I think, 

 back on the limestone ridge, near the town-line between Barton and 

 Glanford. This upper escarpment can be traced through Barton 

 Township into Ancaster Township, and to within a short distance of 

 the lower escarpment at Tiffany Falls, on the farm of Mr. Robb, 

 within one mile of Ancaster village - 



Over the escarpment, between Hamilton and Ancaster, a 

 number of streams flow into the valley beneath. These streams 

 mostly flow in channels cut at right angles, or nearly so, to 

 the face of the escarpment. Amongst the largest, is the stream 

 at Chedoke. This stream has cut for itself a channel about two 

 hundred yards wide at the mouth, and back into the face of the 

 escarpment, nearly five hundred yards. The walls show a clear 

 section of the broken upper band, and in places the heavy bed of lime- 

 stone on which the broken band rests. This limestone is from six to 

 eight feet thick, and the broken material, eighteen or twenty feet. 

 The lower beds, apparently red and bluish colored shales, are hidden 

 by the debris falling from the sides of the ravine, and brought down 

 by the stream. At the head of the ravine the water has cut through 

 the broken material to the solid rock, and falls over a face of fifty feet 

 into a pool excavated in the underlying shales. In NicholPs quarry 

 on the right hand side looking up, and close to the mouth of the 

 ravine, within thirty feet of the level of the bed of the stream ; there 

 are exposed the blue and red shales and sandstones of the Clinton 

 group. From the horizon of these shales, I do not doubt but that 

 they are a continuation of the same beds as are to be found at Dun- 

 das, with an elevation of one hundred and twenty feet above the 



* In this band of chert several species of fossil sponges have been discovered by Lieut-Col. 

 Grant. 



X Geology of Canada, page 323. 



