OF CENTRAL CANADA PART II. 



103 



limestones of the Ottawa region, as at Calumet Falls, and in the 

 townships of Algona, Blythfield, and Dalhousie. Dark-green 

 Amphibole, in good crystals, occurs with diopside at the High Falls 

 of the Madawaska, and elsewhere on that river. A fibrous and 

 acicular pale-grey or greenish variety (Raphilite) is found near 

 Perth, in Lanark County. Actinolite occurs here and there amongst 

 the magnetic iron ores of Madoc and Belmont. Beds of hornblende 

 rock range through Frontenac, North Hastings, &c., in the Lauren- 

 tian area lying between the Ottawa and Georgian Bay j and syeiiitic 

 or hornblendic gneiss occurs abundantly throughout the Laurentian 

 area, generally. See Parts III. and V. Black and dark -green 

 hornblende is seen in distinct crystalline masses and grains in many 

 syenites and diorites ; notably in the large development of syenite 

 in the townships of Grenville, Chatham, and Wentworth, on the 

 east side of the Ottawa: (See parts III. and Y.) South of the 

 St. Lawrence, green hornblende occurs in well-defined examples in 

 the township of Potton : and actinolite is found, with talc, chlorite, 

 fibrous or asbestiform serpentine, &c., in the townships of Brome 

 and Sutton, as well as in beds of fibrous structure in St. Francis, 

 Beauce County. Black hornblende, with garnets, is associated with 

 the Serpentines of Mount Albert, in Gaspe ; and small grains and 

 crystalline masses occur in the diorite and granitic trachytes 

 (Part III.) of Mount Johnson, Yamaska, Brome and ShefFord. 



53. Pyroxene (including Diopside, Sahlite, Augite, <fec.) : Green of 

 various shades, greenish-white or almost colorless, brown, black. Clin- 



orhombicic in crystallization, ^ s 



the crystals mostly eigh t-sided I / 

 prisms with sloping terminal 

 planes, as in the annexed 

 figures. The prism-faces v, 

 v meet (over v) at an angle 

 of 87 5' ; v inclines to v at 

 an angle of 133 33' ; v and 



FIG. 65. 



FIG. 66. 



FIG. 67. 



v' form a right angle. Fig 65 is the 

 combination usually presented by the light or dark coloured vari- 

 eties of our Laurentian crystalline limestones. Fig. 66 represents 

 the ordinary augite crystals of basaltic rocks : good examples occur 

 in the trap of the Montreal Mountain. Fig. 67 represents a 

 twin or compound crystal from Orford, presented to the writer by 



