THE HAMILTON ASSOCIATION. 101 
the presence of argillaceous matter, but to oxide of iron. The 
grey or neutral tinted stones of the same composition are much more 
durable. A mixture of fine sand grains with pebbles does not 
usually answer ; some, however, may .be enduring or little affected 
by weathering, where Silica is the cementing substance.” Every 
stonecutter knows that all rocks are more easily trimmed when 
freshly taken from the quarry than after they have remained exposed 
to the air for any time. I have noticed of late years the freestones 
are more frequently removed to the city in the rough state than 
formerly. I presume there is some reason for it which is quite 
unknown to me. 
Placed as foundation stones, beyond the reach of freezing, 
thawing and the oxidizing influence of the sun’s rays, many of our 
limestone layers can be safely used, which may be considered ob- 
jectionable in more prominent positions above ground. I have 
noticed, for example, in underground kitchens or cellars in Hamilton, 
limestones still retaining unaltered the brassy appearance and lustre 
presented by the base bed of the Niagara series. If the in- 
formation received can be depended on, “that it was quarried a 
fourth of a century ago” the views generally entertained regarding 
this very objectionable mineral may be slightly modified. When 
protected from external influences it may not prove to be quite so 
subject to disintegration. 
Although some of the layers above the Pentamerus bed hold 
large shells (the Stricklandinia of Billings, for instance) they have 
not been mineralized and present no objectionable features, but the 
thick limestone bed known to quarrymen as ‘‘ The Nigger Head,” 
frequently displays pockets filled with Selenite, Baryta, or 
Earthy Gypsum. Sometimes the mineral matter has been dissolved 
and disappears altogether, leaving the empty chamber, which adds to 
the difficulty in shaping the material—even while the cavity is con- 
fessedly very slowly enlarged while undergoing the weathering pro- 
cess. 1 infer from this our Dolomites here are more durable as 
building stones than the corresponding beds in the States, which 
have been pronounced more suitable for rough masonry than other 
building purposes. In the State of New York there are sandstones 
and limestone of various ages, yet you may perceive from what 
scientific men admit, that no superiority can be claimed as regards 
durability except by properly testing. he Amherst freestone so 
