13G 
wash-dirt with fragments of quartz does not prove that it 
was derived from quartz reefs, because any large fragments of 
quartz or other rock remaining unbroken by the alluvial 
action would naturally be found in the low’est stratum. It 
appears to me probable, then, that the gold, as well as all the 
other minerals, are simply the components of the granite of 
the plateau. But such is the minute proportion of the gold, 
that it would scarcely be possible to extract it from granite. 
A ton of dirt seldom contains’more than an ounce of gold, but 
the wash-dirt forms at the most -/o'th P^^rt of the granite-debris 
even in rich hollows, and allowing for those parts which 
contain no gold, I should say that the granite will not 
contain more than YbVo oz. to the ton, which would be quite 
inappreciable. I should also mention that I saw reefs or 
dykes of a dark ferruginous rock, probably trap, but 
running parallel with the other reefs ; in the neighbourhood 
were large masses of porphyry, of which I have a small 
specimen.” 
Mr. H. M. OrxMERod produced two specimens of iron used 
in building, which had both become oxydized so as to injure 
the buildings which they had been used to strengthen. One, 
an iron cramp, taken from the north-west buttress of Man- 
chester Parish Church, about one foot long and three- 
eighths of an inch thick. This had become treble the 
thickness by rust, and had split the buttress, in the centre 
of which it was inserted, lifting about twelve feet of wail. It 
had been inserted about ninety years since. The other, a 
small wedg^e, from the steeple of St. Mary’s Church, in 
Manchester, about three-eighths of an inch thick at the broad 
end originally, but now seven-eighths. These wedges had 
lifted all the stones which they were meant to keep in their 
places, splitting some, and allowing all the rain to penetrate. 
The steeple was erected about 1756, and the upper part has 
now become so ruinous and dangerous from the original faulty 
