Prof. Bonney — Rock- specimens from the Canadian Rockies. 549 



filled, is a rather dark grey limestone, with moderate effervescence, 

 showing on a smooth surface a rudely banded, almost fluxional 

 structure in the form of darker and lighter streaks. Microscopic 

 examination proves it to be a mixture of dirty granular calcareous 

 material, and of a less abundant clear silicate in small grains, and 

 a few flakes, probably of white mica, with sundry brown and blackish 

 specks like iron-oxide ; the whole traversed by rather irregular 

 dark lines, indicative of a rude cleavage. The clear silicate some- 

 times includes very minute rhomboidal scales, and as one or two 

 grains of it show a distinct oscillatory twinning, it is probably 

 a plagioclastic felspar. The glacier which feeds the Yoho River 

 descends from Mount Collie [2033] and Mount Habel [2031], 

 a summit about 1^ miles to the south-west of the other. The 

 summit of Mount Collie is a compact, subcrystalline, not very dark 

 grey limestone, weathering to a browner tint, with faint traces of 

 minute spots which become more conspicuous by forming holes on 

 a weathered surface. As effervescence with H CI is slower than 

 one would anticipate, the specimen is probably dolomitic. The 

 summit of Mount Habel is a grey subcrystalline limestone, full of 

 very small spots, rather irregularly distributed, and weathering to 

 a pale brown coloui", containing also a few white calcitic grains 

 without definite form or size, the largest of which are about -2 inch 

 in diameter. The microscope shows it to be a rather dolomitic 

 limestone, with occasional coarser spots and little patches of brown 

 staining. Here and there the former presence of an organism is 

 suggested, and some rather cylindrical clear bodies, in which granules 

 of the carbonate are embedded, have a very faint resemblance to 

 sponge spicules. Extinction is parallel to the edges, so that if only 

 mineral in origin they may be allied to couseranite. 



The specimens from the Ice Eiver Valley, chiefly crystalline rocks 

 and in many cases sodalite or nepheline syenite, have been already 

 described in the Geological Magazine for this year (p. 199). 



Specimens from the Hoodoos (earth pillars) of Leanchoil (on the 

 Canada Pacific Eailway) [2040] are a pale yellowish clay and 

 a small grey limestone pebble, clearly water- worn, but not in any way 

 remarkable. The former consists of minute micaceous and clayey 

 material, mixed with small angular rock-fragments, stained a rather 

 rusty tint, and difficult to determine exactly — not improbably a 

 siliceous mudstone. Few, if any, quartz grains occur in the mud, 

 which otherwise is not remarkable. It effervesces slightly with H CI, 

 so the material is probably derived from argillites and limestones. 



The above descriptions show that [2107] and possibly [2020] 

 approach the structure of a true marble, such as that of Carrara, or 

 one of those interbanded with crystalline schists in the Alps. 

 Most of them are not more altered than specimens from the 

 Dolomites of the Italian Tyrol (to which one or two of them have 

 some resemblance) or than some of the Triassic rocks from the Swiss 

 Alps. Others resemble Carboniferous Limestone from Britain, and 

 the Trilobites from near Mount Ball and from the flank of Mount 

 Stephen are in excellent preservation. But, though I have sliced 



