294 Professor Bonney — Bpecimens from the Canadian Rockies, 



Desolation Valley specimens. Worm burrows and tracks are not 

 ■very helpful, but Planolites appear to be commonly found in rocks 

 belonging to the Cambrian period, ranging from the bottom to 

 the top. Lithological character also is not the safest of guides, 

 but I may remark that both the white quartzites and the slabs 

 with the mounds remind me of Cambrian rocks, the former being 

 not unlike the basal quartzite of Britain, and the matrix of the 

 latter being more altered than is usual in a rock belonging even 

 to the later part of the Cambrian. So I think we may pronounce 

 the quartzites and argillites from Desolation Valley to be not more 

 modern than Lower Cambrian, the limestones probably belonging 

 to a later part of the Palteozoic. 



Mount Neptuak (10,500 feet) rises at the head of Desolation 

 Valley glacier, on the watershed between the Bow and the Ver- 

 million Rivers, about 12 miles in a direct line from Hector Pass. 

 A specimen " from the ridge " is a limestone (Ca C O3, with a little 

 Mg C O3, a very small amount of insoluble residue, and some 

 carbonaceous matter). In colour it is a pale brownish grey, mottled 

 rather irregularly, and in about equal quantities with a darker shade 

 of the same. The microscope shows it to be a very fine-grained 

 dolomitic limestone, mottled by another rather more coarse, its 

 grains varying about '005 inch in diameter. The finer part is once 

 or twice traversed by a sharply zigzagged dark line suggestive of 

 fracture, and the coarser seems to run up into a crack in the finer 

 material, the latter corresponding with the darker parts of the 

 rock ; it also contains a few thin fragments, straight, or hooked, 

 or more or less oval, probably organic, perhaps molluscan. I suspect 

 that the finer-grained rock has been brecciated in situ and sub- 

 sequently cemented by infiltration. 



The T'emaining specimens come from the northern side of the 

 Canada Pacific Eailway, and at a much greater distance from it. 

 Mount Fresbfield (about 10,900 feet) is on the watershed where 

 it has bent much to the west. It drains on one side to the Bush 

 Eiver (South Fork), on the other to the Blaeberry Creek, which 

 joins the Columbia River. From the Fresbfield Glacier comes 

 a pebble, possibly a rather crushed and decomposed diabase, con- 

 taining perhaps a speck of sodalite. From near the summit of 

 the mountain are two limestones, each rather cui-iously marked, 

 one being yellowish (Ca C O3 with a little Si O3), indicating, I think, 

 local brecciation and recementation ; the other (yielding a white 

 residue and no Mg 0) possibly due to a similar cause. They have 

 a general resemblance to later Palseozoic limestones. 



A specimen from the Bush Pass near Mount Fresbfield is an 

 impure limestone (CaCOs with Mg 0, and some Si Og or Alg O3) ; 

 it affords dubious traces of organisms and may be Palaeozoic.^ 



1 In 1900 Professor Collie (Geogr. Journ., xvii, 1901, p. 268) brought a few 

 specimens from pebbles in tbe bed of the Bush Eiver, some distance away to the 

 west. One is a limestone with oolitic grains recrystallized ; another contains 

 fragments of organisms, ill preserved ; two show a coral which, according to 

 Mr. E. T. Newton, F.H.S., probably in one case, certainly in the other, belongs 

 to the genus Bijjhyphyllum. 



