THE HAMILTON ASSOCIATION. 93 



width ; and the south-west bank rising from this is composed of 

 brown, unstratified clay, concealing the shales and sandstones. The 

 slope of the bank is sometimes steep and sometimes gradual, and 

 upon its flat summit stands the village, extending in a direction 

 parallel to the river for a distance of one mile and a-half in length, 

 and in a direction at right angles to this of one-eighth of a mile in 

 breadth. Carrying a section from the river bed to the south-west, 

 we find, after crossing the main street of the village a slight fall, 

 nowhere greater than fifteen feet to the Canada Pacific Railway 

 (Credit Valley Branch) ; then a slight rise and fall to a small creek, 

 a feeder of the Credit, and finally a rise, gradual at first, succeeded 

 by a low escarpment of about forty feet in height. The lower part 

 of this rise is clayey, while in the middle part is exposed, at a dis- 

 tance of not more than a quarter of a mile south-west of the river, 

 about twenty feet of red Medina shale, with here and there a thin 

 layer of sandstone, striped and spotted with green as usual, destitute 

 of fossils, except a few obscure fucoids. This rock, it may be 

 added, is largely quarried in the manufacture of terra-cotta. 

 Following the strike of the rock a lower layer of red shale may be 

 seen about twenty-five feet below the just mentioned exposure. 

 Finally, near the railroad station, are exposed, in the bed of the creek 

 above referred to, some grey, brown weathering, unfossiliferous sand- 

 stones, distant about one-eighth of a mile north-east from the last men- 

 tioned outcrop of Medina rock. These are probably transition beds, 

 revealing to us the gradual shallowing of the sea bottom with the con- 

 sequent destruction of the organic life of the period. Thus we see 

 that although the actual line of junction between the two groups of 

 rock is not so far visible, yet its position may be approximately 

 found. 



In finding this we perceive another interesting fact, namely, the 

 height of these beds above Lake Ontario. The heights are here 

 given : — 



Height of the uppermost bed of Hudson River sandstone 



on the north-east bank of the Credit 240 feet. 



Height of the unfossiliferous gray, brown weathering bed, 

 one eighth of a mile south-west of the above, and 

 near the railway station 245 " 



