34 Canadian Record of Science. 
felspar existed. These pseudomorphs are usually marked 
by a rim of green or red color, probably due to chlorite and 
iron Oxide, which separated out either previous to or coin- 
cident with the silicification process. Immediately outside 
of these rims there is deposition of chalcedony, which forms 
a feathery periphery extending from all sides into the 
interstices between large quartz grains, which in turn form 
a mosaic in the centre of the spaces between the original 
grains of felspar. 
‘Scattered through the slide, both in the larger grains 
and also in the interstices between these, are little cloudy, 
almost opaque, areas, which under crossed nicols, resolve 
themselves into calcite. The centres of these little areas 
are dark and structureless, while the outer portions are 
composed of the perfectly crystallized mineral. This eal- 
cite has every appearance of having been enlarged, after it 
had once been formed, by the addition of new material 
around the opaque portions in a manner analogous to the 
enlargements of quartz grains, so distinctly shown by Profs. 
Irving and Van Hise, of the United States Geological 
Survey. 
“The present condition of the rock seems to be due to a 
very thorough process of silicification. 
‘No. 303. Strver BLurr, (R. 61).—(About jifty feet below 
contact.) Is of the same general nature as the above. In 
this, however, the calcite occurs with chlorite and other 
alteration products of felspar to form complete pseudo- 
morphs of this mineral. Round and angular grains consist 
now of chlorite and crystallized calcite, mixed with mag- 
netite (which is usually found around the edges of the 
grain), and a brown earthy substance. The outlines of the 
original grains are well preserved by the rim of magnetite, 
but their material has entirely disappeared. From the 
large amount of magnetite and other iron minerals present 
in the slide it may be doubted whether the original grains 
were not augite or some other iron-bearing mineral. 
“A few grains are composed entirely of silica, as in the 
case of section 28]. 
