98 _ JOURNAL AND PROCEEDINGS. 
no shale seams may be detected. In many consolidated sand beds, 
the layers become harder on removal. In other instances the 
opposite takes place, large blocks freshly quarried becoming disinte- 
grated, crumbling away during a night in a mysterious manner. Prob- 
ably frost could throw a little light on the subject. If the rock is of 
a loose texture, or shaly, it absorbs a considerable amount of water, 
and the expansion of this by freezing may sufficiently account for the 
circumstance. As far as I can learn, this has never occurred in our 
Medina freestones, so the texture of the stone is of considerable im- 
portance in Canada. ‘The grey band (freestone) caps the blue, red or 
mottled clay on which Hamilton city is situated, is far and away the 
most valuable stone we possess. ‘The real workable beds average from 
five to six feet in thickness (deducting the passage beds into the Clin- 
tons.) It is generally free from Iron Pyrites, but at certain places 
beneath the brow of the escarpment this may be occasionally noticed 
in small patches. This foreign ingredient is very objectionable, as 
when it decomposes the sulphuret of iron stains the exterior of the 
stene, thereby causing an unsightly appearance. Many of the public 
buildings in New York are built of the brown Medina freestones. 
No worse material could have been selected for the purpose. Dr. 
James Hall states: ‘“‘ Although little more than twenty-five years 
have elapsed since these buildings were erected they already present 
a most dilapidated appearance.” This he attributes partly to clay 
seams in the New York beds, as well as coloring matter. Others 
from the same horizon become harder, more durable than when 
quarried, but less acccessible than formerly owing to its position. The 
cost of removing the overlying shales is increased, the demand too 
slight, the prices unremunerative and far below the actual value. 
This quite explains the cause why so few quarrymen are employed 
here. It is quite possible that in some cases objectionable 
material may have proved prejudicial also, but it is not always an 
easy matter to detect injurious foreign substances in rocks freshly 
quarried. Often the iron stain does not put in an appearance for 
several days, or the mud and dirt may conceal minute fossils which 
shine like brass. - The base of the Nuiagaras, known as the 
Pentamerus bed here, usually contains many large shells metalized 
or impregnated with mineral salts, viz., Iron Pyrites. This is by 
far the most objectionable layer in the Hamilton quarries used for 
building purposes. It is injurious, and even when not immediately 
