EXAMINATION OF CRYSTALLINE ROCKS—HONEYMAN, 299 
Art. VIJII.—Po.ariscoric EXAMINATION OF CRYSTALLINE Rocks 
or ANTIGONISH CountTy.—By Rev. D. HONEYMAN, 
DEC 8S Bas: Cl) Fe Sese 
(Read Apri 12, 1886.) 
THE rocks which I have submitted to this method of examina- 
tion, by sections, prepared by Dr. A. Julien, are the following : 
Ist. Two from the “Typical Archean Series,” on Northumber- 
land Strait. Vide Papers in Transactions of the 
Institute, “Geology of Antigonish County,” Vol. IV, 
1875. 
2nd. A section of the summit rock of Antigonish “ Sugar 
Loaf.” 
3rd. Three sections of the axial rocks of the mountains north 
of the “Sugar Loaf.” 
4th. Three sections of the Crystalline rocks in the “ Arisaig 
Mountains.” 
5th. A section of one of the Avisaig Pier rocks, and another of 
a rock at Doetor’s Brook, on the shore. 
No 1 is an Archean diorite, having the feldspar in large 
patches in hornblende. I have characterized it as “ porphyritic.” 
Our section has both minerals. The hornblende is dichroic. 
With crossed nicols the other part of the section is (a) sepia 
coloured with parallel spaces of dark shade, twining lines, 
indicating a triclinic feldspar; (b) there is also in the white a 
pleochroism. The corresponding part of the rock treated with 
an acid effervesces, showing calcite. 
interposing a section of albite, which also shows a sepia colour, 
without parallels. The effect is very striking. The pale sepia 
of our rock section becomes light purple and the dark shade 
parallels indigo. 
By the same process we have corresponding effect in the see- 
tions of the Nictaux and Wentworth I. C. R. diorites. Trans. 
1884, page 121, Nos. 6, 7, 
