126 CRYSTALINE ROCKS OF N. S. AND CG. B.—HONEYMAN. 
formation at Nictaux, Bear’s River and Cape Cove, Cape Sf, 
Mary’s, Bay of Fundy. These diorites have themselves been 
referred to post-upper Silurian and pre-carboniferous (Devonian) 
time, with similar rocks of undoubted Devonian age, at Arisaig, 
Antigonish County, and East River, Pictou County. (Vide 
papers in Transactions.) Of these I intend to have sections 
prepared for subsequent examination. 
(a.) One section examined by the polariscope, with crossed 
nicols and revolving polariser, shew, first, a brilliant dichroism 
indicating the existence of a large proportion of hornblende. 
The other chief constituent mineral is a triclinic feldspar albite. 
That the feldspar is triclinic is evident from the forms of 
the crystals, medium lines, twining, and other parallels. | When 
the nicols are crossed these are distinctly seen. There are no 
prismatie colours between the parallels. The colors in this case 
are purplish, grey and white. Turning the polariser these are 
seen to change from light to dark, or vice versa. (In the Blomi- 
don basalt section there occur, often, crystals having the same 
character.) There are also opaque forms in considerable number. 
(b.) Examined by the microscope these appear as magnetites and 
pyrites. 
The minerals of this rock are albite, hornblende, magnetite 
and pyrite. 
7. Diorite of the Intercolonial Railway, Cobequid mountains. 
In the Wentworth cutting I have pointed out the singular asso- 
ciation of Lower Silurian claystones, having characteristic fossils 
with crystalline rocks which have every appearance of being 
interbedded igneous rocks. I characterized them as homogeneous 
diorites—(Vide papers “Geology of the I C. R.,”"—Trans. 1873.) 
—they appeared so macroscopically. I have selected one of these 
as a representative of this series and had a section made. This 
is far from being microscopically homogenous ; so that the term 
“homogeneous” is no longer appplicable to these rocks. (a.) 
Examined by the polariseope it shows much dichroism from the 
prevalence of hornblende. The predominence of light crystals 
with median and other parallel lines, indicate the prevalence of 
triclinic feldspar. The colours within the parallels resemble those 
