200 Professor T. G. Bonney — A Socialite Syenite 



observed, underlie the valley, but that on the opposite side of this 

 the centre of the hig;h ran^e is formed of an intrusive series of 

 syenitic rocks, vphich he examined, on Ice Eiver, where they were 

 well developed ; and he continues (p. 122, b), " here the latter 

 are first seen about two miles up the valley from the south-western 

 base of the mountains at its entrance." Those on the east side of 

 the valley are entirely composed of syenite, and further up those on 

 the opposite one, as well as (apparently) those at its head ; and the 

 same mass is continued southward at least as far as the head of the 

 Beaver-foot. It is newer than the slaty Cambrians, but posterior to 

 their cleavage ; this is lost as the rocks approach it, while they are 

 baked and porcellanized. " The intrusive mass itself, though very 

 varied in appearance in different places, is in the main a nepheline- 

 syenite. The form most abundantly represented is a medium- to 

 coarse-grained crystalline rock, composed of felspar, nepheline, and 

 hornblende in varying quantities, with grains of magnetite and 

 some crystals of sphene. The colour generally varies from pale grey 

 to dark grey, becoming nearly black in places when the hornblende 

 greatly preponderates. In such black varieties sphene is par- 

 ticularly abundant. The crystals of the component minerals are 

 occasionally nearly an inch in length, while in rare instances they 

 become almost cryptocrystalline. Other specimens derived from 

 the same occurrence, but found as boulders in the bed of the 

 torrent, have a banded and almost gneissic aspect, and under the 

 microscope prove to contain numerous grains of quartz.^ .... 

 As far as I was able to determine, the mass appears to have been 

 much disturbed, and as it were kneaded together while in a plastic 

 or semi-plastic state. Portions of it have become brecciated and are 

 recemented by similar material, differing only in texture or colour. 

 Veins and crevices, which have evidently been filled by segregative 

 action, also occur, and in these minerals similar to the main mass 

 are developed ; but with them, in considerable abundance, sodalite 

 of a beautiful ultramarine-blue colour is found. In the same 

 veins crystals of ilmenite were observed." After referring to 

 Dr. Harrington's analysis of the sodalite (given below) he con- 

 tinues: "It much resembles lapis lazuli in appearance and would 

 have considerable value as an ornamental stone. It is not confined 

 to a single part of the intrusive mass, as it was found to occur in 

 fragments brought down from the mountains further south in the 

 bed of the Beaver Foot." 



Mr. Whymper informs me that the Ice Eiver Valley lies in the 

 mountain mass to the south of the Canada Pacific Eailway, where 

 it descends in a south-western direction from the summit of Hector 

 Pass to a place called Leanchoil. About three miles south of this 

 the Kicking Horse River is joined by the Beaver-foot River, coming 

 from the south-east, into which the Ice River has already emptied 

 itself; this also follows a general south-west course, thus rising 



^ This mineral, as it happens, does not occur in the specimens which I have 

 examined. 



